نشریه پژوهش های علوم دامی
سال سی و سوم شماره 1 (بهار 1402)

The longevity of cows is crucial to the profitability of a dairy farm, and the culling of cows as a result of major health disorders is a significant risk that threatens production systems today. The possibility of taking diseases into account in the selection of dairy cows depends on the economic importance of the diseases. Mastitis and metritis are common diseases among dairy cows that are considered as risk factors for culling cows. The onset of these disorders can be attributed to factors such as environmental and managerial factors, but there is also evidence of a genetic component to each. Many genes are associated with resistance or susceptibility to mastitis and metritis in cattle, and their alleles have been reported. Subclinical mastitis seems to be one of the most important and damaging diseases threatening dairy cattle herds along with reproductive diseases, lameness and possibly some other common diseases such as Para-tuberculosis. Obviously, reducing production costs supports the profitability of dairy farms. By studying the relationship between the incidence rate and health disorders, in order to minimize the deaths due to health disorders, more emphasis has been placed on the health management of cows. The direct and adverse effects of mammary gland disorders (mastitis and nipple injury) on culling are well documented, while there are differences of results on the correlation between reproductive disorders and culling. Contradictory results may be due to differences in the purpose of the study, population, or the methods used. Many factors such as age, breed, production level, and calving season can play a role in the incidence of diseases.

The purpose of this study is to report the prevalence of clinical mastitis and metritis, moreover to investigate environmental and genetic factors affecting these diseases, to estimate the heritability of disease traits and to measure the correlation between disease and production traits in a Holstein cattle herd. Due to the fact that health records are not recorded in the country's farms in a regular and uniform manner, conducting this research is an experiment to collect this type of information so that in the future models can be provided for all Holstein cows in Iran to consider disease relating traits.

Data of 5052 milk yield from 1796 Holstein-Frisian cows has been gathered that had parturition from 2005 to 2009. In this study, using the 305-day milk production variables, parity, year of calving, the frequency of occurrence of clinical mastitis and metritis in cattle diseases using SAS software, using logistic procedure is estimated. The cows have been studied for all the diseases that occurred in all milking period. In logistic regression analysis, the effect of 305 days of milk and other factors in the occurrence of the disorder was investigated as a binary model. The effect of the lactation period in which the disorder was created was included in all analyzes and the fixed effects included milk for 305 days, calving period, calving year and calving season.Log [p. (1-p)] = b0 + b1 * milk305 + b2 * parity + b3 * calveyear + b4 * calve seasonA coefficient of b1 is assigned for the risk factor of milk production, a coefficient of b2 is assigned for the parturition, a coefficient of b3 is assigned for the factor of calving year and a coefficient of b4 is assigned for the factor of calving season. b0 is the logistic regression estimate if there is no predictor other than the response variable in the model. For each estimate of regression coefficients, the probability level, standard error and 95% confidence interval are also calculated. For a particular disease b1, b2, b3 and b4 are regression coefficients. Estimated genetic parameter in this research was heritability of diseases traits that has been done with ASReml software.

Metritis incidence rate is lower than mastitis. The percentage of animals with mastitis and metritis in the herd was 3.11% and 1.67%, respectively. The average calving interval for metritis incidence was 167.3 days and 129.5 days for mastitis. Data analysis of correspondence of metritis and 305 milk yield, parity, the year and the season of calving showed none of the risk factors had relation with the occurrence of clinical mastitis. The heritability of clinical mastitis and metritis were estimated to be 0.27 and 0.23, respectively. We could not find a relationship between milk production and metritis. Can we consider the increase in milk production as a risk factor for disease occurrence? It is very difficult to prove and explain this relationship and there are many contradictions between the results of other studies. From the lack of a proven correlation between milk production and the occurrence of diseases, it can be concluded that if proper management and nutrition provided based on the biological needs of high-yielding cows, then cows with high milk production will not necessarily suffer from diseases in comparison with low-yielding cows.Genetic studies have shown a positive correlation between mastitis and milk production. Erb (1987) and Dehu and Martin (1984) concluded that high milk production could not be a risk factor for mastitis. A study of Ayrshire cows in Finland found that cows with higher milk production during the previous lactation period were at increased risk for mastitis (Grun et al. 1989 and Grun et al. 1990). There are few documented findings on the association between milk production and the incidence of disease. Of course, it should be borne in mind that "milk production" is not the only risk factor for the disease. Concerning diseases in Holstein dairy cattle it seems the occurrence of the disease can also be the result of breeding and nutrition conditions and management. However, identifying all relevant factors and determining their quality and relative importance is difficulty accessible. It is also not easy to estimate all possible interactions between production and disease traits, even with the efficiency of today's computer technology.

In dairy cattle genetic improvement programs, we suggest to record and estimate the breeding values for disease traits and consider them in multi-trait selections among elite sires. The estimated heritability of metritis was lower than clinical mastitis. Keywords: Holstein-Friesian cows, clinical mastitis, metritis, milk 305 days, heritability.

The efficacy of the use of microelements is an important issue in modern poultry nutrition. Microelements are essential for normal growth and many metabolic processes in living organisms, as they are catalysts or constituents of the enzymatic systems of many cells. These facts, along with advanced knowledge of the importance of microelements in immunological processes and reproduction and the variable content of trace minerals in feed materials, has lead, in commercial practice, to their being added to poultry diets in high amounts, with a large safety margin, often exceeding the birds’ requirements. This can lead to a high concentration of microelements in animals’ excreta and their accumulation in the environment, especially in areas of intensive poultry production (Swiatkiewicz et al. 2014). The nanoparticle, which is at least one dimension reduced to a Nano metric size, exhibits new electrical, magnetic, mechanical, and biological properties, which have been determined as critical factors influencing particle uptake. Therefore, the new phenomena and properties of nanoparticles may have unique potential applications. Pekel and Alp (2011) stated that supplementation with 250 mg/kg of copper decreased blood GSH-Px levels and that this could cause a reduction in tissue cholesterol concentrations. Jegede et al (2015) reported that cholesterol content in the yolk of laying hens egg was reduced in birds fed with 150 mg kg-1 Copper proteinate.

The experiment included 5 dietary treatments, which consisted of a basal diet, the basal diet with 75 or 150 mg/kg of Cu from organig source (Bioplex, Alltech Inc., Nicholasville, KY) and the basal diet with 75 or 150 mg/kg of Cu from nano (Framelco, The Netherlands). The hens were allocated in individual cages (41×23×43 cm) and two cages were considered to one replicate. Before starting the experiment, the live weights and egg production of all birds were recorded and distributed to all cages in similar weight and equal egg production. The lighting schedule was a 16 h light/8 h dark cycle with an average light intensity of 15 lx, which was maintained until the end of the experiment, and fresh water) were provided ad libitum throughout the experiment. At the beginning of this experiment fed on a balanced commercial layer diet two weeks prior to study to allow them to adapt and reach a standard level of egg production (data not shown). The data were analyzed based on a completely randomized design using general linear model procedure of SAS (version 8.0; SAS Institute, Cary, USA). When treatment means were significant (p< 0.05), the Duncan multiple range test was used to compare the means.

Feed intake was not affected by dietary treatments (P >0.05). Different levels of dietary treatments increased egg production compared to the control group (P <0.01). Birds fed diet with 150 mg/kg bioplex and nano copper has a significantly lower feed conversion ratio than control diet (P <0.05). The use of different sources and levels of copper had no significant effect on the quality traits of eggs (P<0.05). All dietary treatments resulted in a significant decrease in cholesterol of yolk (P<0.01) or plasma (P<0.05). Also, the biochemical parameters of plasma were not significantly influenced by the addition of different levels of copper to the diet (P >0.05). Lim and Paik (2006) reported a variable effect of organic Cu on the egg production and egg quality. In the present study, the results showed that the addition of organic and nano copper increased egg mass and production, these results are consistent with Tanika (2004) findings. Eggs are rich source of dietary cholesterol and consumption of high level of dietary cholesterol increases the risk of coronary heart disease (Kritchevsky 2004). Based on the results a significant reduction in egg yolk cholesterol of laying birds fed supplemental copper was seen. These findings are in agreement with previous studies in copper-supplemented birds (Leeson 2004). The significant reduction in yolk cholesterol by feeding copper Bioplex and nano copper shows that organic and nano forms of copper were more effective in reducing cholesterol level when fed to laying birds. This observation agreed with the report of Idowu et al. (2006).

It was concluded that dietary supplementation of 150 mg/kg nano copper and bioplex significantly increased hen day egg production. The cholesterol content in the yolk and plasma of laying hens was reduced in birds fed dietary treatment.

Differences between specific anions and cations have a greater contribution to the physiological performance of animals than their individual effect. The difference between cations and anions in milliequivalents of the diet is referred to as the cation-anion difference or the anion-cation balance (Razzaghi 2009). DCAD manipulation by altering blood buffering capacity, improves milk production in dairy cow (Sanchez 2003). Feeding diets with low DCAD during the Prepartum period is a practical nutritional strategy to increase blood calcium and produce more milk Postpartum. Diets containing low DCAD increased the concentration of hydrogen ions in the blood, resulting in mild acidosis and increased calcium absorption (Moore et al 2000). Decreasing DCAD by feeding anionic salts lowers blood pH and increases the binding of parathyroid hormone to the parathyroid hormone receptor on bone, intestinal, and kidney cells (Goff 2004). However, feeding anionic salts reduces prenatal feed intake due to its bitterness; but it improves postpartum calcium metabolism (Golfert et al 2010). One way to activate postpartum calcium homeostasis is to use DCAD-negative diets in the Prepartum period. Nutrition High-anion diets, commonly known as "anion-salt diets," have been used to prevent milk fever for the past 40 years. One possible reason is that dietary metabolic acidosis increases the tissue response to parathyroid hormone. Therefore, the aim of this experiment was to investigate the effect of anion source type and anion and cation balance on rumen fermentation parameters in dry cows invitro.

This study was done at the Research Farm and laboratories of the Department of Animal Sciences, Faculty of Agriculture, in University of Birjand, using the ruminal fluid of two dry Holstein cows with ruminal fistula. In order to investigate the effect of source and dietary anion-cation difference (DCAD) of dry cow's diet on gas production parameters, ammonia nitrogen concentration(N-NH3), rumen pH and dry matter digestibility in in vitro condition. Basal diet was prepared based on the requirements of dry cows. In the next step, concentrations of calcium, sodium, potassium, magnesium, chlorine, phosphorus and sulfur in the basal diet were determined by atomic absorption spectroscopy and the DCAD of the basal diet was calculated. After this, the anionic salts of calcium sulfate hemihydrates, sulfuric acid, phosphoric acid and monobasic ammonium phosphate were added as a percentage of the diet in solution form to the base diet with a sampler to reach the desired anion-cation balance. The factorial experiment conducted in a completely randomized design with 12 treatments and 15 replications. Anionic salts of calcium sulfate hemihydrates, sulfuric acid, phosphoric acid, ammonium phosphate monobasic and different DCAD levels (-56.6, -11.33 and -17.0 meq/100gDM) were used. Each treatment was including a DCAD level and a sulfur and phosphorus source that balanced according to each element ratio in table of requirements. In the next step, the gas from fermentation was measured based on the modified method of Bloomel et al. (1997). The produced gas pressure was recorded at times of 2, 4, 6, 8, 12, 24, 36, 48, 72, 96 and 120 hours from the beginning of incubation. The data were plotted against time and analyzed using the exponential Schofield model (P = v (1-exp (-k (t)))) in the NLIN procedure of SAS software. At times of 12, 24, 48 and 72 hours after incubation, three vials of each replicate were removed from incubator and after recording gas production, immediately after opening the cap, the pH of each vial was measured Using a digital pH meter (Metrohm 727 pH lab). In order to determine the concentration of ammonia nitrogen after centrifugation of the contents of each vial, 5 ml of clear supernatant was removed from it and combined with 333 μl of 3 N hydrochloric acid and then stored at -20 ° C. Phenol and hypochlorite reagents were used to measure ammonia nitrogen and the adsorption was read by ELISA at 650 nm (Bradrick and Kang, 1980). In order to determine the rumen digestibility of the dry matter, the residues obtained from each vial were oven dried in 60 ° C for 48 hours.

The results showed that the effects of experimental treatments on gas production parameters, rumen pH and ammonia nitrogen concentration were significantly different at different incubation times (p <0.05). The highest gas production potential per fermentable substrate is related to Treatment containing DCAD level of -5.66, which is supplied from two sources of phosphoric acid and sulfuric acid. As expected, the total gas production at 120 hours of incubation and also gas production at t0.5 is related to this treatment. The fermentation rate and time to reach half of the gas production potential in this treatment is average. Therefore, it can be concluded that this treatment has been able to provide suitable ruminal buffering conditions for microorganisms due to good results in DM digestibility too. The highest area below the pH curve of ruminal fluid was related to treatment with DCAD of -5.66, which was obtained from ammonium phosphate and sulfuric acid sources. The lowest level below the pH curve of ruminal fluid is related to the treatment containing DCAD -11.33, which is provided from sources of phosphoric acid and sulfuric acid. The highest ammonia nitrogen production is related to the treatment containing the anion-cation balance of 170 with two sources of sulfuric acid and phosphoric acid. Ammonia nitrogen is strongly influenced by the breakdown of crude dietary protein by microorganisms and the breakdown of the microbial population due to nitrogen recycling under adverse conditions. On the other hand, because the dry matter digestibility has increased at this time and in this treatment, this increase is probably related to the breakdown of feed crude protein due to improved fermentation conditions. In general, the use of phosphoric acid and sulfuric acid sources with the anion-cation balance of -5.66 meq/100gDM improved the gas production parameters, the rumen pH curve under area, and the ammonia nitrogen concentration.

Slaughterhouse rumen fluid contains microbial proteins, volatile fatty acids, microorganisms, vitamins and minerals. Rumen fluid has a very diverse population of bacteria and other microorganisms. Rumen bacteria have a thick bacterial polysaccharide (BPS) coating, so this fluid contains hundreds of bacterial polysaccharide molecules. Rumen fluid activity does not appear to be highly dependent on the diet. Bacterial polysaccharides are potent antigens and remain active even after autoclaving (Muscato et al., 2002). On the other hand, it contains high levels of ammonia and phosphorus, which, when disposed of in slaughterhouses, cause environmental pollution. Its nutrients cause eutrophication when excreted in soil and waterways. It is therefore important to find consistent uses of ruminal fluid (Trit and Schuchardt, 1992). The benefits of recycling these wastes are firstly reducing environmental pollution and secondly producing a feed source for ruminants (Mundal et al., 2013.(Spray drying has recently been used to dry biologically active compounds (Tribizenk et al. 1997). It is a simple, fast, and economical technique for obtaining powder from a solution or a liquid suspension (such as an enzyme suspension) (Bajsic and Kranjsevik 2001). This method is widely used in the pharmaceutical and dairy industries to dry milk, whey, antibiotics, vitamins, and enzymes (DeVos et al. 2010). spray drying changes the liquid to a solid form and causes transport, storage, easy examination, and uniform mixing and distribution in food formulations in small amounts (Tan et al. 2005). Some materials are used in the spray drying method as stabilizers to protect active molecules from heat. These include carbohydrates (such as starch, maltodextrin, and dextrose), gums (gum arabic, acacia gum, alginates, and carginals), proteins (milk proteins, whey, and gelatin) (Aghbashloo et al., 2012), Chitosan (2004). These materials improve stability during the manufacturing and storage process, as well as reducing stress and protein denaturation (Maiori et al. 2005). This study was performed in order that these compounds are biologically active after drying by spray drying, and also ruminal fluid can be converted into an enzyme source.

Slaughterhouse rumen fluid obtained by filtration with 4 hydrocolloids of sodium alginate, guar gum, chitosan and maltodextrin in 1% (volume / weight) ratio was dried by spray drying. The chemical composition of the produced powders including the percentage of dry matter, protein, ether extract, in neutral detergent fibre and non-fibrous carbohydrates were determined. To determine gas production and nutritional parameters, 1 and 2 g of each powder were dissolved in 100 ml of 0.1 M phosphate buffer at pH 6.8 and sprayed on alfalfa grass, wheat straw and silage corn (10). Ml per 5 g of feed) and incubated for 24 hours at 39 ° C. Fresh ruminal fluid and phosphate buffer were selected as positive and negative control groups The method of Monk et al. (1979) was used to measure the amount of gas produced Digestible organic matter, metabolizable energy, short-chain fatty acids, lactation specific energy and total volatile fatty acids were estimated using their own formulas.

The results showed that there was a statistically significant difference between dried rumen fluid with different hydrocolloids and without hydrocolloids in terms of chemical composition (P <0.05). The highest percentage of crude protein was related to dried rumen fluid with 1% maltodextrin. The amount of gas produced from incubation of alfalfa hay with processed ruminal fluid was significant at all times except 24 and 48 hours after incubation (P <0.05). Gas production parameters were significantly different (P <0.05). In the case of wheat straw and corn silage, the amount of gas produced was significant at all times except 6 and 12 o'clock (P <0.05). The highest amounts of digestible organic matter (DOM), metabolizable energy (ME) and specific lactation energy (NEL) were related to wheat straw processed with fresh rumen fluid. The highest values of nutritional parameters were related to corn silage processed with rumen dried with 2% maltodextrin. Changes in gas production kinetics of enzyme-treated feeds have been reported previously. Elghandour et al. (2013) stated that increasing doses of an enzyme preparation from a ruminal bacterium, Ruminococcus flavefaciens, increased gas production from four fibrous feeds at all incubation times. Similarly, rate of gas production in two of the four fibrous feeds increased in response to higher doses of the enzyme preparation. Colombatto et al. (2003) observed higher in vitro ruminal organic matter digestibility for enzyme-treated feeds using an in vitro gas production method. This effect is attributed to the increase in degradation rate achieved via a combined effect of direct enzyme hydrolysis and synergistic action between the endogenous (ruminal) and exogenous enzymes. Wallace et al. (2001) examined the effect of two enzymatic preparations on the fermentation of corn and grass silages using an in vitro ruminal gas production method and reported that the rate of gas production increased at concentrations much higher than the recommended application rates. They also observed the highest correlation between increased gas production and enzyme activities against micro-granular cellulose (Wallace et al., 2001).Nutritional parameters, amount of metabolizable energy, total volatile fatty acids, digestibility of organic matter in silage corn were also significantly affected by dried rumen fluid with different hydrocolloids (P <0.05).

This study showed that dried rumen fluid with different hydrocolloids is biologically active and alive and has the ability to become an enzymatic source. Maltodextrin hydrocolloids are also more successful among hydrocolloids in maintaining protein percentage, gas production, and nutritional parameters. Therefore, slaughter ruminal fluid is of great value.

By-products can have an important role in supplying livestock feed. Using these resources as a substitute for conventional resources decrease their demand for animal feed. One of the most common sources of demand is soybean meal. Optimal use of poultry by-products meal as a source of protein is one of the suggested solutions to decreases demand for soybean meal. Poultry by-products meal is said to be parts of poultry carcasses that have been milled if dry or wet, such as heads, feet, Intestines and viscera and except for feathers. Note that even in a good slaughterhouse there is a small amount of feather. The fat by more than 16% accelerates the Spoilage of this product, Therefore; it is recommended that the fat of these products should not be more than 10 to 12% (Gheshlagh Oliai et al. 2010; Watson 2006). Its chemical composition depends on the source of raw material, storage time of raw materials before processing, processing method, pressure and temperature during preparation and the amount of ash in the raw material (Jan Mohammadi et al., 1388). In order to use this by-product, the analysis of chemical composition and its effect on animal performance must be studied. The present study aimed to investigate the possibility of replacing protein sources conventional (soybean meal) with poultry by-products meal in the diet of fattening lambs and changes in growth, rumen and blood parameters, microbial population and microbial protein yield.

In order to investigate the effect of replacing the waste powder of poultry slaughterhouses with soybean meal, 16 male Dalagh mixed lambs with an average weight of 29 ± 0.5 kg were tested at the research site of the Animal Science Department of Golestan Agricultural Research and Training Center. The experiment was performed in a completely randomized design with 4 replacement levels and 4 replications. The diets of the lambs were adjusted according to the sheep nutritional requirements table (National Research Association 2007), with the same energy and protein levels. The lambs were fed a total mixed ration at two times on day with free access to water. Treatments (diets) included: control (soybean meal), 33% replacement, 67% replacement and 100% replacement of poultry by-product meal with soybean meal. Rumen fluid sampling was performed to measure ruminal parameters including volatile fatty acids, ruminal pH and ammonia nitrogen concentration through the stomach tube 3 hours after feeding. Determination of ammonia nitrogen concentration was measured by phenol hypochlorite (Broderick and Kang, 1980) and volatile fatty acids using gas chromatography. The culture medium PAC was used to count the microbial load (AOAC, 2005) and Protozoa count was performed by Dehoerti (1984) method. Protozoa were counted under a 40% magnification microscope with a neobar slide. Blood samples were taken from Neck veins at the same time as ruminal fluid sampling for the concentration of total protein, urea nitrogen and sugar of blood. measurement of microbial protein yield in the rumen was performed by estimating excreted purine derivatives by Chen and Gomez (1995) method in the end period.Urine was collected for 4 consecutive days. The sample collection containers contained 100 sulfuric acid to keep the pH below 3 and were frozen until the sample was tested.

At the end of the fattening period, no significant difference was observed in the gain characters: dry matter intake, weight gain of the period, average daily weight gain and feed conversion ratio. Changing the protein source to 10% of dry matter did not affect the palatability of the diet. Its efficacy for fattening indices has also been similar to that of soybean meal. There was a significant difference in blood urea nitrogen (P <0.05) and no significant difference was observed for other blood parameters (glucose and total protein). The comparison of the means between the treatments shows that treatment of 33% has a significant difference with the treatments of 66 and 100%. However, there was no significant difference between the control diet and 100% replacement. Also, blood urea nitrogen concentration was in the normal range. The correlation between NH3H and BUN and the lack of significant differences in blood glucose and protein concentrations indicate that the replacement of soybean meal with poultry by product meal in isocaloric and nitrogenic diets in 10% of dry matter has a similar effect on metabolism and physiology. Diet without poultry by-product meal has a higher bacterial population (P <0.01) and comparison of the mean effect of dietary protein source replacement levels on the protozoa population of ruminal fluid was not significantly different. The treatment of replacement 33% showed the highest level of ruminal NH3N (P <0.05). Acetate concentration was not significantly different between treatments and the concentration of propionate for treatment was 33% and 67% higher than other levels (P <0.01). Also, the ratio of acetate to propionate was significantly different (P <0.05). The pH of ruminal fluid for replacement levels was 33% and 67% lower than the control treatment (P <0.05). Replacement of the protein source in the diet with a constant content of nitrogen and carbohydrate concentrations did not alter the ruminal ecosystem. The effect of replacement levels on the mean of microbial protein production was not significantly different. Therefore, by replacing a similar nutrient in the diet and on the other hand, the internal conditions of the body and the tendency for homeostasis can be interfering in the synthesis of microbial proteins.

This study showed that the replacement of soybean meal with poultry by-product meal in lambs fattening diets up to 10% of dry matter did not have a negative response on fattening performance, blood and ruminal parameters. Also, it can reduce the demand for soybean meal in the rations.

Among agricultural activities, aquaculture has shown the highest growth among food production sources in the last two decades. According to the F.A.O., aquaculture is the best supply of the maximum motivation for poverty alleviation. Uncertainty and risk in the aquaculture subsector, like other agricultural subsectors, are formed due to unfavorable weather conditions, the prevalence of diseases, and price fluctuations. Naturally, due to uncontrollable factors and risks, the efficiency of production units is expected to decline. Identifying sources of these risk in aquaculture activities is one of the key points for risk management. It is clear that risk can never be eliminated, but it can be managed by identification. Zanjan province is one of the major fish farming regions of the country and among them is the city of Mahneshan which accounts for about 65% of the total fish production of this province.

The purpose of this study is to the identification of risk management tools in fish farms and their effect on the technical efficiency of these farms in Mahneshan county. To this end, the stochastic frontier production function was applied and the required data were collected by surveying a questionnaire by stratified proportional random sampling from salmon farms in three-zone including Central, Angoran, and Oryad in Mahneshan county in 2020. In general, risk management strategies in the agriculture sector were divided into two categories: in-farm risk management strategy and off-farm risk management strategy. These two categories are classified into 8 risk management tools and then measured by the Likert spectrum. The Cobb-Douglas functional form was selected to estimate the stochastic frontier production function.

The results showed that among the in-farm risk management strategies, the selection technology with less risk tool is the most popular and the tool of the financing method is very common in the off-farm risk management strategies. In address to the comparison between In-farm and Off-farm’s risk management strategies, the fish farmers are more likely to use in-farm risk management strategies. The estimated results of the Cobb-Douglas production function showed that the total area of pools, number of baby fish, labor, and feed cost, Floating usage, and Aerator usage have a significant effect on fish production. According to the results, if the total pools area increases by one percentage, the frontier fish production will increase by 0.06 percentages, and if the number of baby fish increase by one percentage, the fish production will increase more than one percent. After estimating the frontier production function, the technical inefficiency model was estimated. The results showed that with increasing age, the technical efficiency rise and enhancing the participation to the fish training courses and being fish breeding as the main job, have a positive effect on the technical efficiency so that it improves significantly. Also, increasing the number of pools and being fish farming as the main job has a positive effect on the technical efficiency of farms. Regarding the impact of risk management tools on the technical efficiency of fish farms, it was observed that the technology selection with fewer risk tools has a negative impact, and the flexibility tools, and the use of marketing contracts tools have a positive effect on breeders' technical efficiency. So, by using these tools, the technical efficiency of the farms also increases. Finally, the technical efficiency of the farms was calculated and results revealed that about 50% of farms have an efficiency of more than 90%, and farms with a pool area of 1000-1500 square meters with 89% efficiency, have the highest technical efficiency.

The results showed that among the in-farm risk management strategies, the selection technology with less risk tool is the most popular and the tool of the financing method is very common in the off-farm risk management strategies. In address to the comparison between In-farm and Off-farm’s risk management strategies, the fish farmers are more likely to use in-farm risk management strategies. The estimated results of the Cobb-Douglas production function showed that the total area of pools, number of baby fish, labor, and feed cost, Floating usage, and Aerator usage have a significant effect on fish production. According to the results, if the total pools area increases by one percentage, the frontier fish production will increase by 0.06 percentages, and if the number of baby fish increase by one percentage, the fish production will increase more than one percent. After estimating the frontier production function, the technical inefficiency model was estimated. The results showed that with increasing age, the technical efficiency rise and enhancing the participation to the fish training courses and being fish breeding as the main job, have a positive effect on the technical efficiency so that it improves significantly. Also, increasing the number of pools and being fish farming as the main job has a positive effect on the technical efficiency of farms. Regarding the impact of risk management tools on the technical efficiency of fish farms, it was observed that the technology selection with fewer risk tools has a negative impact, and the flexibility tools, and the use of marketing contracts tools have a positive effect on breeders' technical efficiency. So, by using these tools, the technical efficiency of the farms also increases. Finally, the technical efficiency of the farms was calculated and results revealed that about 50% of farms have an efficiency of more than 90%, and farms with a pool area of 1000-1500 square meters with 89% efficiency, have the highest technical efficiency.

Given that producers use risk-reduction tools rather than transferring risk on farms and this also harms the technical efficiency, so it is recommended that in a progressive world to take advantage of modern production technology, a great facility should be provided.

Digestion and absorption are related to the growth and development of ruminal villi and intestinal villi and one of the most important factors affecting the growth of ruminal epithelium is diet and increasing the villi height and villi surface increases the absorption capacity and helps maintain ruminal pH (Wang et al. 2009). Epithelial tissue cells play an important role in maintaining stable ruminal conditions, and changes in morphology predispose to the dysfunction of these tissues (Korasani et al. 2021). Pomegranate peel contains large amounts of secondary metabolites such as tannins, saponins, and polyphenolic compounds with various properties such as antimicrobial, antioxidant, anti-inflammatory, and immune-stimulating effects (Adams et al. 2006). The main feature of tannins is their binding to proteins, which inhibits the action of enzymes. Tannins can inhibit the activity of microbes and inactivate extracellular endoglucanase in some fiber-digesting bacteria (Babadi et al. 2018). Tannins prevent the digestion of lignocellulosic substances that are dependent on extracellular enzymes, prevent microbes from attaching to food particles, reduce their digestibility, and make them more persistent in the rumen (McSweeney et al. 2001). Bacteria, yeasts, and filamentous fungi are capable of producing tannins. Bacterial tannase can effectively break down and hydrolyze natural tannins and tannic acid (Kumar et al. 2015). Tanase produced by Klebsiella pneumoniae is more stable in the acidic pH range of 4.5 to 5.5. Therefore, the tannase produced by Klebsiella pneumoniae is of high value for various industrial applications due to its acidophilic nature and thermal stability (Kumar et al. 2015). Several researchers have reported that strains of Klebsiella pneumoniae are able to degrade phenolic compounds; in fact, using bacteria could overcome tannins by altering, destroying, and inactivating tannins. These isolates are likely to increase pectinase and cellulase activity by altering the pH and reducing the toxic effects of tannin; in fact, reducing phenols and tannins increases digestibility by ruminal microorganisms. Therefore, in tropical and subtropical regions, the processing of tannin-rich trees with tannase is very important in animal nutrition systems (Mohammadabadi et al. 2020).

The present experiment was performed in the educational-research farm and laboratories of Khuzestan University of Agricultural Sciences and Natural Resources. Fifteen Arabic male lambs with nine or ten months old and initial body weight of 39.75±7.91kg were used in a completely randomized design with three treatments and five replicates. The trial period consisted of 35 days including 14 days of habituation period and 21 days of recording period. The lambs were randomly assigned to one of the three treatments: 1- control (diet without pomegranate peel) 2- control diet + 20% pomegranate peel 3- control diet + 20% pomegranate peel treated with Klebsiella pneumoniae, which produces tannase. The diets were adjusted using the small ruminant's nutrition requirements (NRC 2007). The lambs were fed a fully mixed ratio at two meals (8 and 16 hours) with free access to water. At the end of the experiment, the lambs of each treatment were slaughtered. The parts about one square centimeter were separated from the abdominal area of rumen and reticulum and one cubic centimeter from liver and kidney and each sample were fixed separately in a 10% solution of neutral formalin (khorasani et al 2021). Micrometric studies including villi height, villi thickness, villi depth, epithelial thickness, muscle layer thickness, and ruminal wall thickness were examined histomorphometrically.

The thickness of epithelial tissue and papillae thickness of reticulum in the treatment containing pomegranate peel treated with bacteria were less than other treatments (P <0.05). The thickness of epithelial tissue and papillae thickness of rumen in the treatment containing pomegranate peel treated with bacteria were less than other treatments and were significant compared with the treatment containing pomegranate peel (P <0.05). The height and depth of ruminal villi in the control treatment were significantly higher than other treatments (P <0.05) and this difference was greater than the treatment containing bacteria. The most important pathological finding in the rumen was translucent corneum hyperkeratosis which was more strongly observed in the treatment containing pomegranate peel. In the treated group with bacteria, basophilic casts (possibly minerals deposition) in the kidneys was reduced compared with the treatment of pomegranate peel. In the treatment containing pomegranate peel, due to the reduction of digestibility of nutrients including cellulosic substances and the decrease in the activity of cellulolytic bacteria in the rumen, the thickness of epithelial tissue and villi thickness increased compared with the treatment containing pomegranate peel processed with bacterial, Because bacterial tannase reduces tannin and actually increases the activity of cellulolytic bacteria and increases acetate production (Mohammadabadi et al. 2020). The reduction of translucent corneum hyperkeratosis in the treatment of pomegranate peel treated with tannase-producing bacteria can be attributed to the reduction of tannin in this treatment and its role in increasing the uptake of ruminal fatty acids compared with the treatment containing pomegranate peel (Khafipour et al. 2009). The presence of basophilic casts into the urinary tubules and glomerular hyperemia can be attributed to oxalate and phytate in pomegranate peel (Romelle et al. 2016).

Compared with control and pomegranate peel treatments, the treatment of pomegranate peel treated with Klebsiella pneumoniae can improve the status of rumen and reticulum tissue markers and relative reduction of ruminal tissue lesions and the severity of basophilic casts in the kidneys compared with pomegranate peel treatment. Therefore, considering the total of these benefits, the use of Klebsiella pneumoniae in the consumption of foods containing tannins can be recommended.

Industrial poultry farming on a large scale and intensively has increased the possibility of disease outbreaks. Studies have shown that the use of antibiotics, in addition to environmental threats, causes microbial resistance in the body (Yakhkeshi et al. 2011). The presence of chemical residues in poultry products and its impact on human health was one of the reasons for the ban on the use of antibiotics in 2006 (Garcia et al. 2007). Much research has been done to find suitable alternatives to antibiotics. Essential oils and plant extracts with a variety of biological and physiological compounds have a very high potential for their use as new medicinal compounds (Hussain et al. 2008). Useful properties of medicinal plants are related to the presence of secondary metabolites in them (Efterpi et al. 2012). In addition to improving bird growth and production, medicinal plants have positive effects on health status parameters (Grashorn, 2010), intestinal microbial population (Bolukbasi et al. 2008), serum concentration of antibodies to viral diseases (Toghyani et al. 2010) and biochemical and hematological parameters (Toghyani et al. 2010). Among the medicinal plants, cinnamon, marjoram and pepper are aromatic herbaceous plants that are of great importance and have effective healing properties. In some studies, consumption of cinnamon in the diet has caused weight gain, decreased feed conversion ratio and improved liver function in broilers and mice (Mehdipour et al. 2013; AL-Kassie, 2009). Giannenas and Et al. (2005) reported that consumption of marjoram extract improves the performance of broilers. Capsaicin in pepper increases intestinal and bile secretions, increases the activity of pancreatic enzymes, slows the passage of substances in the intestine, and increases the absorption of nutrients (Farrell, 1978). Platel and Srinivasan (2003) reported that consumption of capsaicin by 0.15% in the diet increased salivary amylase secretion in mice; it also increased gallic acid salts by 17%. It has been reported that the consumption of several medicinal plants simultaneously has a greater effect on the production, functional and health parameters than the consumption of one medicinal plant alone (Mehdikhani, 2015). Farrokhnia et al. Reported in 2020 that the consumption of a mixture of Thymus vulgaris and Echinacea angustifolia extracts was reduced due to a reduced conversion ratio of broilers compared to separate consumption. According to the above, the aim of this study was to investigate the effect of consumption of a mixture of cinnamon, marjoram and pepper extracts on performance, weight and relative length of gastrointestinal tract, enzymes and blood minerals in broilers. This experiment was performed using 192 Ross 308 broilers in a completely randomized design with 4 treatments, 6 replications and 8 broilers per replication in a 42-day breeding period. Experimental treatments are: (1) base diet, (2) base diet + 50 mg/kg mixture of plant extracts, (3) base diet + 100 mg/kg mixture of plant extracts and (4) Base ration + 200 mg/kg mixture of plant extracts. Functional parameters of feed intake, weight gain and feed conversion ratio were measured at the end of 42 days of rearing. On the last day of the experiment, 3 chickens were selected from each replicate for blood sampling. Samples were transferred to the laboratory to measure the activity of alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase; These parameters were measured by an autoanalyzer and commercial kits of Pars Azmoun Company. Also, the amount of calcium, phosphorus, magnesium and iron elements in the blood were measured by autoanalyzer by spectrophotometry (Biowave model S2100 made in England) by commercial kits of Biochemistry Company. Then the birds were slaughtered and after filling, separating the ventricular contents and separating the components, the relative weights of different parts of the gastrointestinal tract were calculated in terms of body weight, and the relative lengths of the duodenum, jejunum, ileum and cecum were measured (Daneshyar et al. 2012). Experimental data were statistically analyzed in a completely randomized design by SAS statistical software (2003) using GLM linear procedure. Mean comparisons were performed using Tukey-Kramer test at 5% level. The results showed that feed intake and feed conversion ratio were not affected by experimental treatments (P>0.05). However the treatments receiving 100 and 200 g/ton of mixed plant extracts had more body weight gain than the control treatment (P<0.05). Consumption of all three levels of plant extracts resulted in a significant increase in the length of jejunum and ileum of chickens (P<0.05). On the other hand, duodenum and cecum length were not affected by experimental treatments (P>0.05). There was no significant difference between the relative weights of the duodenum, jejunum, ileum and cecum between the experimental treatments (P>0.05). The results showed that the levels of liver enzymes aspartate, transaminase and alkaline phosphatase were not affected by experimental treatments (P>0.05). However, consumption of 100 and 200 g/ton of plant extracts reduced the amount of alanine aminotransferase and lactate dehydrogenase in comparison with the control treatment (P<0.05). The results showed that the consumption of a mixture of plant extracts had no significant effect on the amount of phosphorus and iron in the blood serum of broilers (P>0.05). On the other hand, consumption of 200 g/ton of mixed plant extracts compared with the control treatment increased the amount of calcium and magnesium in the blood of broilers (P<0.05). From this study, it is concluded that up to 150 g/t of a mixture of Cinnamomum verum, Origanum vulgare and Capsicum annuum extract in broiler diet without changing feed intake led to improved weight gain and increased relative length of ileum and jejunum in broilers. Liver enzymes were at normal levels and even showed a decreasing trend; The blood calcium and magnesium levels of broiler chickens also increased. Therefore, up to this level, a mixture of cinnamon, marjoram and pepper extract can be used in broiler diets.

The ability of an animal to survive in the breeding period is called the survival trait. One of the most important features of survival analysis is unfinished (censored) observations. In other words, the event under study does not necessarily occur at the time of recording the observations. Thus, survival observations and data are generally incomplete, and events occur for some people but for others there is no observation for that event. In general, nonparametric regression methods (Kaplan-Meier estimator, Cox hazard ratio model) and parametric methods are used for this type of analysis more than other methods. Survival and longevity analysis is performed by linear, threshold and hazard ratio functions methods. Linear models are easier to use, but due to the nonlinearity of the survival trait, they are skewed, and the estimates of heritability with this method are low and close to zero. Threshold models are more accurate and obtain higher genetic estimates. In the analysis of hazard ratio method, the accuracy is higher than previous models due using the more information (use of censored data), but it is time consuming and its computational load is higher. Therefore, the aim of the present study was to estimate the genetic parameters and the effect of fixed factors on the survival of Makuie sheep lambs up to one and two years of age using the proportional hazard function under Weibull distribution.

In this study, 2332 records of Makuie lambs that collected between 1986 to 2010 in Makuie sheep breeding station, were used. In the first step, fixed factors affecting longevity (gender, type of birth, year of birth, month of birth, birth weight, weaning weight, weaning age and age of dam) Was investigated by LIFEREG procedure of SAS statistical software version 9.4 under Weibull distribution. Then significant effects were used in the survival analysis with the proportional hazard model. Survival up to one and two years of age were analyzed using the Weibull hazard model by SURVIVAL KIT software, version 6.12. SURVIVAL KIT software is able to provide components of genetic variance and can estimates breeding values for animals using mixed models. Survival from post-weaning to one year (for analysis up to one year of age) and two years (for analysis up to two years of age) were assessed by day.

In the analysis of survival from weaning to the one year of age, 38.12% of observations and in the study of survival up to the two years of age, 13.68% of the observations were censored. According to the study, the year of birth had a significant effect on the survival of lambs. The year of birth affects the amount of rainfall and ultimately the availability of food resources by affecting the pasture, and thus changes the quality and amount of nutrition. survival up to one year of age Lambs born in 2004 and for survival up to two years of age lambs born in 1994 had the lowest risk of elimination. Lambs born in 2010 had the highest risk of elimination. Scrutiny the effect of birth month on the survival of lambs, it was found that for survival up to one year of age, lambs born in April had a higher risk of elimination. However, for survival up to two years of age, lambs born in May had the highest risk of elimination and the amount of risk for May compared to March was 1.96. Lambs born in May reach autumn at a young age and during a period of rapid growth. Because the studied flock is kept semi-densely, access to feed for these lambs is reduced and they are removed from the flock due to their low weight and insufficient growth rate. Birth weight is one of the most important components affecting the survival rate and directly affects the elimination rate. Threshold weights have the highest elimination risk ratio and the weight of 3.5-4.7 kg has the lowest elimination risk ratio for survival up to one and two years of age. There is a curved relationship between elimination risk and birth weight, so with increasing birth weight to medium weight (3.5-4.5 kg), the risk ratio decreases and then increases. Mortality at low weights is due to the inability to control body temperature and high mortality at high birth weights is due to infertility. Weaning weight is an important factor influencing survival after weaning. Similar to birth weight, weaning weight has a curved relationship with survival. So that with increasing the weaning weight from 10 kg to 19 kg, the risk of elimination for survival to one and two years of age decreases from 1.8 to 0.97 and 0.93, respectively, and then with increasing the weaning weight, risk ratio reaches to 2.53 and 2.38, respectively. Lack of growth-induced production encourages the elimination of low-weight weaned lambs. So the elimination risk ratio is high at low weights. But as the weaning weight increases, the desire to keep it for later periods will be greater, and thus the removal pressure will be lower. The average weight of weaning in the herd is equal to 19.01 kg, the results also show that the lowest elimination risk ratio and consequently the highest survival for weaning weight is 18-20 kg. Therefore, in order to increase the survival and reduce the elimination risk ratio, management and corrective programs can be designed to select the optimal weaning weight. For survival up to one and two years of age, the risk of elimination for male lambs was higher than females. In the period between weaning until the age of one year, the elimination risk ratio for male lambs was 2.17 relation to females and for survival to the age of two years, the elimination risk ratio of males was 2.61 Compared to females. This difference in elimination rate can be attributed to sex-related factors, sex characteristics that may not have yet been discovered, systemic diseases, different management practices for males and females, and high elimination rate for males due to surplus fattening. There are three types of births in Makuie sheep (singles, twins and triplets). Lambs born with twins and triplets have lower birth weight and weaning weight than single lambs. Due to the above topics, low birth weight and low weaning weight, reduces the survival and, increase the risk of elimination. Another reason for the reduced survival of multiple births is the limitation in dam milk production, which can be due to poor maternal genetics or inadequate nutritional intake. Heritability of survival to one and two years of age for Makuie sheep lambs according to the censorship ratio of 38.12% and 13.68% (respectively) was 0.062 and 0.079, respectively.

Since heritability was estimated at a low level, control of environmental factors and management will play an important role in improving the survival of Makuie lambs.

Conocarpus is an ornamental plant common in tropical and subtropical regions that is usually seen as a shrub with a height of 1.5 to 4 meters. Due to resistance and adaptation to hot and dry environment, poor drainage, air pollution and dense soils, its cultivation has increased in the last decade in the country and especially in Khuzestan (Mohammadabadi 2020). Al-Koaik et al (2014) reported the amount of crude protein and fiber of conocarpus leaves were 96.6 and 134.7 g/kg, respectively. Also, Direkvandi et al (2020) reported the amount of crude protein, NDF and ADF of conocarpus silage were 114, 473 and 371 g/kg DM, respectively, which can be used as feed with suitable nutrients in animal feeding. However, one of the things that should be considered about conocarpus as animal feed is the presence of secondary compounds such as phenolic compounds (tannins) (Mohammadabadi 2020). Treatment with microbial additives has been suggested to reduce tannins (Konda et al. 2007). These microbes contain the tannin acyl-hydrolase (tannase) enzyme, which hydrolyze tannin to gallic acid and glucose (Jafari-Tapeh et al 2012)

In this experiment, 16 Arabi lambs (average body weight, 25 ± 3 kg) were used in a completely randomized design with 4 treatments and 4 replicates. The experimental period was 60 days (10 days adaptation and 50 days trial period). Four treatments were included; (1) Control group (without conocarpus); (2) BA6, diet containing conocarpus treated with bacterium A6; (3) BA8; diet containing conocarpus treated with bacterium A8; (4) WB, diet containing untreated conocarpus. During the experimental period, the complete mixed ration (based on 50% forage and 50% concentrate) was provided for each lamb twice daily at 8:00 am and 16:00 pm (allowed 5% of orts) (NRC, 2007). Lambs had free access to fresh water and salt licks. At the end of the experiment, feed intake (daily basis), feeding behavior (in a 24-hour period), nutrient digestibility (sampling on days 45 to 50 according to Givens et al 2000) and rumen fermentation parameters (pH, ammonia-N, volatile fatty acids and protozoa population; sampling on day 50 of the experiment at 0, 3 and 6 hours after morning feeding), were evaluated. Also, blood sample (approximately 10 mL) was collected from jugular veins using tubes containing an anticoagulant (heparin) on day 50 of the experiment at 0, 3 and 6 hours after morning feeding. Glucose, triglycerides, blood urea nitrogen (BUN), cholesterol, low-density lipoprotein (LDL), high-density lipoproteins (HDL), alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine transaminase (ALT) were determined by using enzymatic methods and spectrophotometer.

Results showed that the amount of feed intake decreased by experimental treatments (P <0.05) and in all cases the lowest amount of feed intake was observed in WB treatment (P <0.05). Similarly, Hosseini (2018) reported that the use of conocarpus silage reduced feed intake compared to control. Reduction of feed intake in treatments containing conocarpus is probably due to less palatability of these treatments. Feeding time and the rate of chewing was significantly decreased by the experimental treatments (P <0.05). The lowest rumination rate was observed in BA8 treatment (P <0.05). In contrast, the lowest rest period was observed in control and BA6 treatments (P <0.05). The highest digestibility of organic matter was observed in BA6 treatment (P <0.05). The lowest digestibility of NDF and ADF was observed in WB treatment (P <0.05). Digestibility of NDF and ADF showed no significant difference between BA6, BA8 and control (P <0.05). According to our results, Mohammadabadi et al (2021) also reported an increase in digestibility of cell wall as a result of treated with tannin-degrading bacteria. The highest and lowest pH values were observed in control and WB treatments, respectively (P <0.05). The concentration of Ammonia-N and protozoa population were significantly decreased by experimental treatments (P <0.05). The reducing effect of conocarpus-containing treatments on ammonia-N and protozoa populations may be due to more phenolic compounds in these treatments (Yanez Ruiz et al 2004). Total concentrations of volatile fatty acids, propionate, valerate, isobutyrate and isovalerate were not affected by experimental treatments (P <0.05). The concentration of acetate significantly increased by BA6 and BA8 treatments (P <0.05). Also, the highest concentration of butyrate was observed in WB treatment (P <0.05). The increase in acetate concentration in BA6 and BA8 treatments may be due to the increased digestibility of cell wall in these treatments. Blood glucose concentration and BUN were significantly decreased by experimental treatments (P <0.05). The high concentration of propionate and glucose was observed in the control treatment. Hosseini (2018) similar to our results reported that the use of conocarpus silage and dried conocarpus had no significant effect on triglyceride, cholesterol, HDL and LDL concentrations compared to the control. The concentration of liver enzymes in this study was not significant but was numerically higher than the control, which agreed with the results of Rezaeinia et al. (2012).

The results of this study showed that due to the positive effects of the conocarpus treated with tannin-degrading bacteria than the untreated conocarpus on some measured parameter, and also due to the lack of a negative impact on animal health, it can be said that the treated of this plant to reduce tannin that is a suitable solution for the use of conocarpus in the ration of lambs.Keywords: Tannin-degrading bacteria, Feeding behavior, Blood and ruminal parameters, conocarpus, Arabi lambs