مجله پژوهش در نشخوار کنندگان
سال یازدهم شماره 3 (پاییز 1402)

The use of dairy by-products as a new feed source in order to reduce the costs of raising livestock is very important. Whey powder is a residual cheese or casein, which is one of the animal proteins used in the human food chain. It is also a feed source of protein and contains some useful minerals. Whey can be used in the diet of livestock due to its proper nutrient balance. Also, the fact that whey can reduce the consumption of concentrate without any negative effect on daily weight gain and feed conversion ratio, so the purpose of this study was performed to investigate the effect of using different levels of whey powder in diet on growth performances traits, apparent digestibility of nutrients and some blood parameters in fattening male crossed Zell lambs.

To perform this study, 24 mixed fattening Zell lambs were examined with a means age of 4.5±0.52 months and a means initial weight of 24±2 kg in a completely randomized design for 90 days. Experimental treatments included control treatment (without adding whey powder in the diet) and treatments containing 1.5, 3 and 4.5% whey powder in the diet. Chemical analysis of whey powder used included pH, 6.8 to 5.8, protein 12.5%, lactose 64%, fat 1.5%, moisture 4.5%. Whey powder used in the study was given to the experimental animals at different levels after mixing with the diet. The daily diet was given as a TMR to the animal twice and the amount consumed was recorded. Live weight measurement was performed every 14 days with 12 hours of feed and water deprivation. Measurement of the apparent digestibility of nutrients in the last days of the experiment as well as the study of carcass traits and blood parameters were performed on day 90 of the experiment.

The growth performance results of experimental lambs showed that there was a significant difference in end weight, DMI and daily weight gain between experimental treatments (P <0.05); So that the highest final weight and daily weight gain was observed in the treatment containing 4.5% whey and the highest dry matter intake was observed in the treatment containing 3% whey. The results of apparent digestibility of nutrients showed that there was a significant difference in apparent digestibility of dry matter, crude protein and NDF between experimental treatments (P<0.05). The highest apparent digestibility of dry matter and crude protein was observed in the treatment containing 4.5% whey and the highest apparent digestibility of NDF was observed in the treatment containing 3% whey. The results of some blood parameters showed that there was a significant difference in the concentration of glucose, triglyceride, HDL and BUN between experimental treatments (P<0.05). The results of quantitative traits of carcasses of fattening lambs showed that there was a significant difference in hot carcass weight, hot carcass percentage, cold carcass weight, cold carcass percentage, thigh percentage and shoulder percentage between experimental treatments (P<0.05). The results of qualitative traits of carcasses of fattening lambs showed that there was a significant difference in the rate of TBARS of the straight muscle 48 hours after slaughter between experimental treatments (P <0.05).

The overall result of the present study showed that the weight at the end of the fattening period, dry matter intake and also the apparent digestibility of nutrients were significantly improved by consuming 3 and 4.5% levels of whey powder. There was a higher carcass percentage and improvement in valuable carcass parts in the treatment containing 3% whey powder.

Selecting a breed with appropriate economic performance is one of the most challenging decisions that cattle farmers have to make. The Holstein breed has been imported to the country in the past few decades to increase milk production. This breed is scattered in different climates of Iran, including Golestan province, almost without previous study. Holstein is a breed with high milk production and sensitivity to heat stress. This breed in Golestan province did not have suitable reproductive and economic indicators. On the other hand, dual-purpose breeds, such as Montbéliarde, experience less thermal stress with less feed consumption. Therefore, the research was conducted to evaluate the performance of some reproductive traits and milk production of the Holstein breed, Montbéliarde breed, and hybrids to recommend a suitable breed in the region.

This study was carried out to evaluate the economic characteristics of some reproductive traits and milk production of Holstein cows with Montbéliarde cows and their crossbreeds in Golestan province in northern Iran. In this study, 395 cows were evaluated in the form of a completely randomized design. Indicators such as the age of first insemination and calving, open days, calving interval and the number of inseminations leading to fertility, length of pregnancy period, calf birth weight, and milk production Holstein, Montbéliarde, and 50:50 and 25 crosses: 75 Holstein x Montbéliarde were studied for 5 years in the same geographical point and same management. Meteorological data from 1390 to 1399 was analyzed with the approach of drawing the conditions of livestock breeding environment.

Investigating the results of long-term meteorological data showed that the temperature-humidity index has been above 68 for almost six months, and high-yielding dairy cows in this region are probably experiencing heat stress conditions. Based on the data of this research, Holstein cows showed more open days, so the number of inseminations leading to fertility in this breed increased, and the cost of maintenance, feed, as well as cost artificial insemination, and delay in pregnancy on the farm increased. The calving interval in the Montbéliarde breed, Holstein mixed with 75% Montbéliarde x 25% Holstein, 50% Holstein x 50% Montbéliarde was 398.31, 392.42, 387.59, and 421.72 days, respectively.

Conclusion:

The results of this research showed that the reproduction efficiency of Montbeliarde breeds cows in Golestan province was better than Holstein breed, moreover, heavier calves were produced. It seems that heat stress conditions in the region were more effective in Holstein cows with higher milk production. In an economic evaluation of milk production and herd longevity without considering meat production, the Montbéliarde breed was better than Holstein. It seems that breeding the Montbéliarde breed in the warm and semi-tropical conditions of the north of Golestan province is a more suitable option than the Holstein breed.

Studies had shown that excessive production of free radicals during sperm processing decreases its quality parameters including motility, viability, and fertilizing ability. Therefore, it seems necessary to use a compound with antioxidant properties during this process. Evening primrose oil has antioxidant properties due to its phenolic compounds. the purpose of this research is to investigate the effect of adding evening primrose seed oil to freezing diluent on the quality of ram sperm after freezing and thawing process.

In this research, the semen of 5 adult Romanov rams with an average age of 3 to 4 years and average weight of 60 to 65 kg were used. Semen collected using artificial vagina from trained rams twice a week. The treatments included control (without evening primrose seed oil), treatment 1 with 25 microliters EPSO, treatment 2 with 50 microliters EPSO, treatment 3 with 100 microliters EPSO. The collected semen sample to laboratory and examined in terms of volume, concentration and motility. Semen samples were diluted with a diluent based on Tris- lecithin soy and frozen. After thawing, parameters of general mobility and progressive mobility and other parameters related to mobility were evaluated. The survival percentage, membrane integrity, mitochondrial activity and peroxidation were determined.

The results showed that the level of 25 microliters of evening primrose seed oil improve the motility of the whole sperm compared to the control group, and no significant difference was observed in other experimental treatments compared to the control group. There was no significant difference between the 25 and 50 microliters treatments with the control group in the progressive parameter, but there was a significant difference with the 100 microliters treatment compared to the other treatments and the control treatment(P<0.01).The results of lipid peroxidation showed that the lowest amount of Malon-di-aldehyde production was related to the 25 microliters treatment but no significant difference was observed with the control treatment. The results of the apoptosis test showed that the addition of levels of 25 and 50 microliters of evening primrose seed oil decreased the amount of apoptosis compared to the control group and the level of 100 microliters of evening primrose seed oil(P<0.01). Also, survival in the treatment of 25 and 50 microliters compared to others The treatments had a significant difference and increased survival(P<0.01). And finally, dead sperms in the 25 microliters treatment were less compared to other experimental groups, and this caused a significant difference in this trait compared to other levels(P<0.01).

In general, the addition of evening primrose seed oil in the freezing diluent leads to an increase in the viability and health of the plasma membrane of sperms after thawing. Adding 25 microliters of evening primrose seed oil to the diluent caused a significant difference in the parameters of lipid peroxidation and apoptosis compared to the control treatment.

Crossbreeding is a common method for exploiting genetic differences between different breeds of a species, during which offspring are usually obtained from two pure breeds through mating, which are expected to have parental traits. to improve, which includes productive traits and traits related to the health and survival of the animal that each of the parents may have superiority in one of these traits, therefore, hybridization with the aim of combining the superiority of parental traits and improving them in the results It takes place. In sheep, cross-breeding is a well-known method to improve production, including meat, milk, wool, and reproduction. Depending on the parent breeds and their purity percentage, different results may be observed in the offspring. On the other hand, food ration is a determining factor in the manifestation of the genetic power of livestock, and in the meantime, the anion-cation balance of the diet (DCAB) plays an important role by affecting the acid-base balance and homeostasis of the body. Since maintaining the acid and base balance of the body is related to the maintenance of the animal and is preferable to reproduction, lactation and growth, therefore the performance of the animal is significantly affected by the change in the acid and base balance. Therefore, the purpose of this research is to investigate the difference of diet anion-cation on performance, blood and digestion parameters and rumen parameters.

In this study, 30 Lori Bakhtiari and Lori Bakhtiari × Romanov × Pakistani lambs with an average age of 90 ± 10 days and an average weight of 32.9 ± 1.5 and 32.25 ± 1.5 kg respectively used. The lambs were placed in two racial groups in the form of a 2x2 factorial design and with two levels of anion-cation difference (DCAD) of -100 and 100 milliequivalents per kilogram of dry matter for 90 days. The whole fattening period was 84 days and anionic diet was used in the last 14 days of the period.

Based on the results of this study, dry matter consumption, weight gain and feed conversion ratio were not affected by breed. However, dry matter consumption decreased in lambs that consumed anionic diet (P<0.003). Also, blood parameters, apparent nutrient digestibility, ammonia nitrogen concentration and rumen fluid pH were not affected by diet and breed.

The results of this study indicate that the mixing of Lori Bakhtiari breed with foreign breeds has no effect on its fattening characteristics, and the use of anionic ration, along with its potential benefits, can lead to a reduction in dry matter consumption, so according to the results This research suggests that anionic or cationic rations can be used for fattening animals with various purposes without significant effect on growth performance and digestibility of nutrients as well as parameters related to rumen fluid

Heat stress in most parts of the world has a negative effect on the performance of dairy cows and reduces milk production in dairy cows. Supplementation of cows with micronutrients (minerals and vitamins), especially in the close up period, can have benefits in reducing the negative effects of heat stress and improve the yield of cows during the next lactation period. This study was conducted to investigate the effect of some nutrients on the physiological and performance processes of dairy cows in heat stress.

In this research, 24 multiparous dairy cows were used in the transition period. The cows were randomly divided into 2 groups of 12 and each group was assigned to a test treatment. Treatments include control group: only from the common diet and without nutritious additives and the second group, which in addition to the common diet, received a micronutrients for 21 days before parturition. After parturition, each of the control and treatment groups were again subdivided into two groups of 6, so that in each group, they were either fed with diets without micronutrients or enriched with micronutrients until 21 days after parturition.The supplement containing a micronutrient of the close up period, including micronutrients of selenium, copper, zinc, chromium, beta carotene, vitamin E, magnesium, ascorbic acid and niacin and the micronutrient supplementation of the freshly period in addition to the micronutrient above, contained sodium and potassium. The average temperature- humidity index was during the text period of 74 and cows were heat stress. The conditions of maintenance and management of nutrition and environment were the same for all the animals during the whole experiment period. Weight variations, feed intake and rectal temperature were determined each week 4 hours after feed intake in two consecutive days. The weight of the newborn calves, the weight of the placenta and the amount of colostrum produced during the first three milking was recorded.

The amount of dry matter intake during close up was higher in the micronutrient intake group than the control group, and in the last week of pregnancy there was a significant difference between them (P<0/05). Although weight gain during the close up was not affected by treatment, more weight gain was observed in the group receiving micronutrients. The numbers of pregnant days in cows receiving micronutrients were longer than the control group. The birth weight of calves in cows receiving micronutrients was higher than the control group. colostrum was also more produced in this group. Calves weaning weight was not affected by treatments. Feed intake during the lactating period was affected in the first week of lactation and receiving micronutrients transition period treatment in the third week had the highest feed intake, which in parallel with this week the milk production of this group was higher than other groups and its difference with other treatments was significant(P<0/05). Milk composition were not affected by treatments (P>0/05).

This experiment showed that heat stress can have a negative effect on the performance of dairy cows during the transition period and the use of micronutrients in this period can have beneficial effects on the repair of heat stress in dairy cows.

Gastrointestinal tract infections and subsequent diarrhea are the main reason of mortality of newborn calves. Diarrhea is the most common disease that occurs in cattle farms and causes death and serious economic losses to the livestock industry. Due to negative effects of antibiotics, including Bacterial resistance to antibiotics, many countries in the world have banned the use of these antibiotics in the animal industry since 1996. The use of probiotics is mostly seen as an alternative to antibiotics in animals, and many scientific works show the beneficial effects of supplements with probiotic strains in the diets of different farm animals. Probiotics have been shown to have positive effects on the whole body, including weight gain and immune function, and reducing the presence of pathogens. This study aimed to evaluate the probiotics Bacillus coagulans and Bacillus subtilis and their effect on the growth performance, health, and prevalence of diarrhea in suckling Holstein calves. . . . . . .

The present study was conducted in the form of a completely randomized design with 32 replications in two treatments. Calves were monitored for 28 days. Body weight was measured every week, and dry matter intake and health status were checked and measured every day. Blood samples were taken from the calves on the first, seventh, 14th, 21st, and 28th days, and the blood was kept at 4°C until reaching the laboratory, and then blood parameters were measured. fecal samples were taken for microbial culture on the 7th, 14th, and 28th days and were cultured in the laboratory.

The results showed that probiotic supplementation does not affect weight, daily weight gain, skeletal growth, Feed Efficiency, and hematological parameters. However, feed intake and the number of Lactobacillus in feces increased significantly (P < 0.05). Additionally, probiotic supplementation reduced fecal score, diarrhea duration, and body temperature significantly (P<0.05).

Probiotic oral supplement improved the symptoms of diarrhea and the negative effects of diarrhea, and it also improved the performance of feed consumption and increased the beneficial bacteria of the gastrointestinal tract system in suckling calves. By preventing diarrhea, probiotic supplements can reduce the losses caused by calves dying and, as a result, make dairy farms more profitable.

Du to limitation of feed resources in Iran, recently research workers tried to find new feed resources, where they introduce new fodder beet varieties to farmers. Regarding the characteristics of the fodder beet, it must be preserved as silage for progressively use in animal feeding, but no appropriate technology was stablished for ensiling of fodder beet. Ensiling is the well nown technology for preserving of fresh forages, but it is difficult to ensile the fodder beet, because of very low dry matter (DM) content. However, using additives (dry roughages and concentrates) as total mixed ration may be applied as a technology for preserving fodder beet silage. Therefore, this research was conducted to prepared a total mixed ration (TMR) silage based on fodder beet in comparison to corn silage and determine their nutritive values in sheep.

Three experimental diets including: 1) TMR based on corn silage (CTMR), 2) TMR silage (CTMRS) based on similar formula of treatment 1 and 3) TMR silage based on fodder beet (FBTMRS) were prepared. Digestibility and voluntary intake of the treatment diets were determined with three treatments and five replicates by in vivo method, using of 5 mature male Shal sheep (with 5 years old age and 80 kg body weight).

The DM contents of the CTMRS and FBTMRS waere 40 and 39.7 percent with pH of 3.95 and 4.06 respectivly. Average daily DM intake (DMI) was 1294g in control, 1301g in CTMRS but 1579g in FBTMRS that were significantly higher (P<0.05) in FBTMRS. Organic matter (OM) intake was significantly (p<0.05) higher (1450 vs 1206 and 1214 g) for the FBTMRS than the other treatments. Similar trend was obsereved when the intake was calculated based on methabolic body weight. Digestibility of DM, OM, organic mater in dry mater (DOMD) and neutral detergent fibre (NDF) were respectively 71.6, 74, 69.1 and 51.5 percent for CTMRS that were statistically (p<0.05) higher than those of the other treatments but no differences were obtained between the control and FBTMRS. The rumen pH, was affected (p<0.05) by the treatments before morning feeding so that it was the lowest in control, but the highest in FBTMRS (6.11 vs 6.85 and 7.01). However, rumen pH was not varied between the treatments at 3h and 6h post feeding. The rumen ammonia nitrogen (NH3-N) showed an increasing tendency in all treatments from morning feedint to 3h post feeding with the highest amount for treatment FBTMRS (from 17.85 to 32.89 mg/dL) and the lowest for the control (from 13.35 to 31.32 mg/dL) but it showed a decreasing trend from 3h to 6h post feeding with slower tendency for the treatment FBTMRS.

Results of the experimental diets on sheep nutrition indicated that, the highest DM and OM intake was obtained when the animals received TMR silage based on the fodder beet. However, the TMR corn silage showed the highest nutrients digestibility that may be due to the nutritional improvement during the silage fermentation and preservation. Improvement the nutrients digestibility of TMR corn silage is considered as an advantage when compared to the normal TMR (contained corn silage). Therefore, TMR silage based on corn forage recommended as superior treatment in this study. However, practicing and utilization of TMR silage based on the fodder beet is recommended, where the fodder beet is available.

The past few decades have seen a dramatic decrease in the fertility of dairy cows. Thus, reproductive performance became one of the main concerns in the dairy cow industry. Improvement of fertility increases the farmer’s income by reducing the culling rate, increasing milk production, and reducing the calving interval. Factors involved in reproductive management are multifactorial such as management, nutrition, and genetics. Synchronization protocols are one of the main management tools that have improved the reproduction of high-producing dairy cows. Nevertheless, the efficiency of these protocols is still not satisfying and the current study was carried out to improve the double Ovsynch protocol in postpartum dairy cows.

A total of 318 healthy postpartum dairy cows were used in the current study. Data of parity and milk yield (1st and 2nd months) were recorded for all cows. Briefly, on 40 DIM, cows were subjected to a double Ovsynch program and were checked for corpus luteum via ultrasonography on d 57, at the start of the 2nd Ovsynch. Cows without CL were divided into two groups including control (DO-CL, continuing the routine program), and DO+CIDR (including one progesterone supplement). Those bearing CL were considered as DO-CL receiving routine injections. All cows were checked for pregnancy via ultrasonography on d 32, 60, and 120 post-AI, and pregnancy per artificial insemination (P/AI) and pregnancy loss rate were calculated. Data were analyzed using the GLIMMIX Procedure of SAS software.

Cows bearing CL at the start of TAI Ovsynch, compared to DO-CL and DO-CIDR groups, had significantly higher P/AI on d 32 (50.84 vs. 29.27 and 41.46%, P = 0.03), 60 (45.76 vs. 21.95 and 36.58%, P = 0.01), and 120 (43.22 vs. 21.95 and 34.14%, P = 0.03) post-AI. Although cows with CL at the start of the TAI program had 15% lower pregnancy loss compared to the control group, this trait in the 2nd (P = 0.31) and 3rd-4th month (P = 0.75) was not significantly affected by treatments. Parity (primiparous vs. multiparous) had a significant effect on P/AI on d 32 (P = 0.04), but not on d 60 (P = 0.17) and 120 (P = 0.28) post-AI. The effect of milk yield (M ≥ 36 vs. M ˂36) on P/AI at d 32 (P = 0.003), 60 (P = 0.001), and 120 (P = 0.001) was significant. Dairy cows in M ˂36 group compared to M ≥ 36 had significantly higher P/AI on d 32 (52.96 vs. 35.63%), 60 (46.62 vs 28.11%), and 120 (44.41 vs. 26.08%) post-AI. The effects of treatment × parity (P = 0.41) or treatment × milk yield (P = 0.45) interactions were not significant.

Improvement of P/AI via evaluating the presence of CL at the start of the TAI program and using a progesterone insert in cows without CL suggests an important role of progesterone during the growth of ovulatory follicles. Therefore, the identification of cows not bearing CL and applying progesterone is highly recommended. However, the difference between P/AI in cows that received CIDR compared to those in diestrous suggests that using a CIDR may not be sufficient and two CIDRs should be applied in order to achieve optimum results.