نشریه پژوهش های علوم دامی
سال بیستم شماره 2 (پاییز و زمستان 1389)

In this study the gas production technique was carried out using two sources of inocola (rumen and feces liquor from sheep) firstly to characterize the effect of four different processing methods on digestibility of untreated barley grain (UBG) and treated barley grain (SRBG = steamrolled barley grain، MWBG = micro waved barley grain، RSBG = roasted barley grain and MLBG = milled barley grain)، and secondly to find out the accuracy of using feces a as inocola in gas production technique to evaluate concentrate feedstuff. In in-vitro gas production technique triplicate grounded and dried samples of each treatment (approximately 300mg) were weighed and placed in 50 ml capacity serum bottles; then bottles were incubated in 20 ml of buffered rumen fluid/faecal liquor (buffer: rumen fluid، 2:1، v/v) for 48 h. The data at the different times was analyzed using completely randomized design. The results showed that in rumen liquor at 48 h microwave processing group had the most and steam rolled barley grain had the least total gas production (275. 9 and 239. 14 ml/gDM، respectively) (P<0. 05)، but the gas production at 48 h using feces as inocola، did not significant difference. Percentage of organic matter digestible in MWB and UBG (65. 14 and 65، respectively) was maximum compared to RSGB and SRGB (58. 21 and 57. 83، respectively) was achieved. Also we found a high relationship (r2=0. 9) between gas production (ml/mg DM) with two sources of inocula which suggests that feces can be used successfully in gas production technique to evaluate concentrate feedstuffs. The results suggest that because of considerations of disorders like acidosis or bloat، use of processing like steam flaking and roasting in order to bypass some of starch to the small intestine can be helpful. The data showed that the faecal liquor can be used as a replacement assay for rumen liquor in gas production technique resulting in low costs.

In this research 17620 records of growth traits of Moghani sheep breed collected during 1994 to 2005 in sheep breeding station of Jafar-Abad, were used to estimate the genetic and phenotypic trends. The Best Linier Unbiased Prediction (BLUP) from breeding value was estimated by Derivative Free Restricted Maximum Likelihood (DFREML) with univariate and multivariate animal model. The trends were estimated by regression of mean of estimated breeding and phenotypic values on birth year. Phenotypic trends were positive and significant (P<0.05) for birth and 3 months weights and are negative for 6 months, 9 months and yearling weights. Genetic trends were positive and significant for all traits in both models for lamb weights at birth, 3 months, 6 months, 9 months and yearling of age being 0.0055, 0.0053, 0.0052, 0.0061 and 0.0849 kg per year in univariate analysis (P<0.01) and 0.0107, 0.0968, 0.1311, 0.1613 and 0.1328 kg per year in multivariate analysis (P<0.01), respectively. Multivariate model offered better results in comparison with univariate models.

Livestock insurance as one of the appropriate strategies of risk management can increase the investment security in this subsection. The present study investigates effective factors on adoption of native livestock insurance in Salmas County at West Azerbaijan province. Required data were obtained by completing questionnaires form 152 cattleman at 1387 year. The results revealed that 62 percentages of cattleman did not use insurance due to insufficient amount of indemnity, high insurance premium and long waiting time for acquiring the indemnity. Estimation of the logit model showed that variables include age, education, revenues fluctuation, amount of revenue, number of dead cattle, number of cattle, awareness level of insurance benefits, having non-livestock farm occupation and obtaining debt, were effective factors on adoption of livestock insurance. Hence, the information of the cattlemen about the insurance can be enhanced by participating insurance training courses.

In order to survey the effect different levels of pre and postpartum dietary cation-anion difference (DCAD) on milk production, milk composition, plasma mineral concentration and health status twenty four Holstein cows were used in a split-plot in time design with a 2×2 factorial arrangement as a completely randomized design. Before calving, cows were divided into two groups of 12 each, one group was fed by a diet of -100 DCAD (meq/kg DM) and another group by +100 DCAD (meq/kg of DM). After parturition animals in each group were divided into two group of 6 each and one group fed a diet of +200 DCAD (meq/kgDM) and the other fed a diet of +400 DCAD (meq/kgDM). Feed intake was recorded weekly and blood samples were collected on days -12, -2, +2and +12 of parturition. Prepartum feeding of the diet with -100 meq/kg DM DCAD increased plasma concentration of Ca, Mg, Cl and S. After parturition, feeding the diet with +400 DCAD increased significantly (P<0.01) DMI, fat corrected milk production, milk fat and total solid concentrations and plasma Na and K concentrations. Prepartum DCAD did not affect plasma mineral concentration, DMI, and milk production of lactating cows. No case of milk fever was observed in dairy cows. However, different levels of DCAD did not significantly affect retained placenta and hypocalcemia incidences, their risks were reduced for animals fed anionic diets. So it was concluded that low level of DCAD on late gestation can be useful to improve animal health and high of DCAD after parturition had positive effect on animal performance.

An experiment was conducted to evaluate the effects of different levels of raw and heated grass pea (Lathyrus sativus) seed on growth performance and some blood metabolites of broiler chickens. Fourteen day old broilers (210 chickens) were randomly assigned to 7 treatments, with 3 replicates and 10 birds in each replicate. Broilers were fed the isocaloric and isonitrogenous diets containing 0, 10, 20 and 30 % of raw or heated grass pea seed. Feed intake, weight gain, feed conversion ration (FCR), European efficiency factor (EEF) and carcass characteristics were recorded. Total plasma protein, triglyceride and cholesterol concentration of broilers were measured at 2 stages of growth (28 & 42d). The results showed that diets containing 20 and 30% raw grass pea seed, increased feed intake significantly (P<0.05) and heated at 30% level increased feed intake significantly (P<0.05). Heating the grass pea seed improved weight gain and FCR of broilers in different levels. The birds which received 20% raw or 30% heated grass pea seed had significantly greater (P<0.05) liver weight than the control group. Total plasma protein concentration was affected by treatments at 28d. At 42d, the birds which received 30% raw grass pea seed had significantly (P<0.05) lowest cholesterol concentration. Increasing the levels of raw grass pea seed, decreased cholesterol concentration. It was concluded that heating process have some beneficial effect on grass pea seed used in chicken diets.

This study was done to investigate subclinical pregnancy toxemia and effect of feeding with propylene glycol (PPG) to supply glucose precursor to prevent ketosis and increase fetal growth. In this study, 40 pregnant ewes, 21 days before parturition belonging to two genetic groups and having 1 to 3 parities were used at Khalatposhan research station, faculty of agriculture, university of Tabriz. PPG was used at 4 levels zero (control) and feeding 420 gr of PPG at three different periods. Blood samples were taken before and after feeding with PPG. Thereafter, blood glucose, and blood serum urea and total protein concentrations were measured by spectrophotometer. The data were analyzed using a general linear model and primary concentration of each metabolite was used as covariate. The weight of ewes, lambs at birth and weaning were recorded. Experimental results indicated significant effect (P<0.01) of PPG on blood serum glucose concentration while total serum protein, lambs birth and weaning weights did not affect by PPG. Control group significantly (P<0.05) had lower blood glucose and upper serum concentrations. PPG, genetic groups and parity had significant (P<0.05) effect on ewes body weight while genetic group had very significant (P<0.01) effect on birth and weaning weights of the lambs. It can be concluded that PPG with increasing blood glucose concentration can reduce pregnancy toxemia in ewes.

An experiment was conducted to study the relationship between behavioral and metabolic characteristics of acidosis challenged cows with their health. Eight Holstein cows in early lactation stage were allocated to four dietary treatments in a change over design with factorial arrangement of 2×2 including two levels of alfalfa hay particle size (5 and 20mm theoretical length cut) and two levels of TMR dry matter (without and with adding water up to 50% DM). The results showed that ruminal pH measurements in cows were in safety margin, however some characteristics such as blood bicarbonate (21 vs 24 mg/dL), fecal particle size (4 vs 1.18 for fecal critical particle size), TMR sorting by cows (sorting for long hay from 19 mm sieve) and feed intake fluctuations indicated that the cows suffer from acidosis. In comparison with spot measurements of ruminal pH, metabolic and behavioral characteristics on animal can be used more efficiently for detection of acidosis challenged cows.

An experiment was conducted to evaluate effects of different dietary calcium and available phosphorus levels on growth performance, tibia ash percentage, apparent retention of calcium (Ca) and total phosphorus (tP), and some blood parameters in male broiler chickens. Five hundred frothy male broiler chickens from Arbor Acres plus (AA+) strain were used in a completely randomized design with a 3×3 factorial arrangement of treatments and 4 replicates with 15 chickens in each floor pen. Broiler chickens were fed three levels of dietary calcium (NRC recommended level, 80% or 60% of NRC recommended level) and three levels of phosphorus (NRC recommended level, 80% or 60% of NRC recommended level) during 7- 45 days of age. Apparent digestibility of Ca and P was measured on 45 days of age. Experimental diets were formulated to be isoenergetic and isonitrogenous with similar nutrients except than calcium and total phosphorus. The results showed that body weight gain, feed intake, blood serum P concentration, serum alkaline phosphatase level and apparent digestibility of Ca were increased and serum Ca level was depressed by increasing dietary level of Ca (P<0.05). Body weight gain, feed intake, blood serum P level and tibia ash percentage were decreased and apparent digestibility of tP and level of serum alkaline phosphatase were increased by decreasing in level of dietary level of available P (P<0.05). Different dietary level of Ca and P had no significant effect on feed conversion ratio throughout the experiment. Interaction of calcium and available phosphorus levels had a significant effect on body weight gain, feed intake, apparent digestibility of Ca and P, Ca and P levels of serum, levels of serum alkaline phosphatase and tibia ash percentage (P<0.05). To achieve the best performance results, ratio of Ca:P is recommended 2:1 according to the results obtained from the current experiment. The results of this experiment suggested that NRC (1994) Ca requirements for modern broiler chickens are excessive, but current NRC available P requirement is sufficient.

This study was conducted to determine the effect of dry rolling on nutritional value of barley grain and comparison of digestive coefficients of diets contented of processed grain associated with two nitrogen sources (urea and soybean meal) in Mehraban sheep. In this study, six head of Mehraban ram were used as change-over design. Experimental rations according to dry matter basis included: ration 1 (stem of alfalfa and barley grain), ration 2 (stem of alfalfa and dry rolled barley grain), ration 3 (stem of alfalfa and barley grain with urea), ration 4 (stem of alfalfa and dry rolled barley grain with urea), ration 5 (stem of alfalfa, barley grain and soybean meal) and ration 6 (stem of alfalfa and dry rolled barley grain and soybean meal). The crude fat digestibility had significant difference between first and second rations (P<0.05) and digestibility of other nutrients had not significant differences (P>0.05). Also calculated digestibility coefficients of whole barley grain and dry rolled barley grain had not significant difference except of crude fat (P>0.05) and dry rolling didn’t change dramatically on digestibility of barley grain. Comparison of six experimental rations was showed which digestibility of nutrients especially crude protein and crude fat influenced by rations significantly (P<0.05) and NFE digestive coefficient of dietaries lacked significant difference (P>0.05). In general can be concluded that, rolling process was not effective on nutrients digestibility and nutritional value of barley grain in sheep but use of protein nitrogen sources and non protein nitrogen sources can affect nutrients digestibility of total dietary.

Identification of associated genes with energy balance, yield and feed intake are recent interests of the animal breeding researchers. With consider to rich resources of animals, in our country-Iran, accomplish a little assay for identification of genes that controlling its traits with molecular techniques. Identify the candidate genes in sheep breeds using DNA test can have a great help for their breeding progress. In this research, for analysis of leptin gene polymorphism in Kermani sheep, we collected blood samples of one hundred and twenty male and female Kermani sheeps which were rearing in breeding center of Shahre Babak, Kerman. Genomic DNA was extracted using commercial DNA extraction Kit. The exon 3 (275 bp segment of exon 3) of leptin gene was amplified with specific primers. The single stranded conformation polymorphism (SSCP) patterns of PCR product were studied using Acrilamid gel and silver staining method. We obtained 10 band patterns for leptin gene: A/A, C/C, A/B, A/C, A/B/C, A/B/E, A/B/F, A/C/F, A/B/D/E and A/B/C/F. The results showed that leptin gene is so polymorphic in studied population.

Twenty- seven multiparous southern Khorasan cross-bred goats (DIM of 71 ± 12.5, average daily milk yield of 1.09 ± 0.13 kg and average BW of 28 ± 2.5 kg), were used to study the effects of feeding pomegranate seed pulp (PSP) on dry matter intake (DMI), milk yield and milk composition, average daily gain (ADG) and some blood metabolits. Goats in pre-trial period (10 d) were fed similar ration and during this period DMI, milk yield and composition were recorded. After this period and based on pre-trial records, the goats randomly were assigned.to one of three experimental diets and were housed in individual stall barns. Experimental diets that were included 0, 6 and 12% of PSP (DM basis) that fed as totally mixed ration and ad-libitum for a 45-d period. The diets were formulated to be iso-nitrogenous and iso-caloric. Results showed that use of PSP did not affect DMI and ADG of goats. Milk production tends to (P< 0.05) decrease with increasing level of PSP in diet. Milk fat concentration of goats fed diets with 6 and 12% PSP, increased by 8 and 15%, respectively but milk fat yield, milk protein concentration and yield and milk SNF concentration and yield of goats was not affected by diets. Milk lactose concentration in goats were fed with 6 and 12% PSP, increased significantly compared with control group. Feeding PSP did not any significant effect on blood glucose, cholesterol, urea N, triglyceride and lipoproteins. It was concluded that pomegranate seed pulp as a cheep feedstuff source can be replaced with part of energy rich feedstuffs in goats.

To evaluate the effects of some environmental factors on the probability of being pregnant after only one insemination in Iranian Holstein cows, a total of 38074 records obtained from 10726 cows at different parities and inseminated during years 1985 to 2009 were utilized. All records were collected from a very large dairy herd which comprised of two units. A generalized statistical linear model was applied to analyze the data. Logistic regression model was applied as the statistical model. In the model, fixed effects of period and month of insemination, inseminator, parity and herd unit were included. The statistical model was run using GLIMMIX procedure of SAS software. Odds ratio estimation for period 1 (years 1985 to 1990) in comparison to periods 2 (years 1991 to 2000) and 3 (years 2001 to 2009) was 1.106, 1.133 respectively, which means chance of being pregnant after first insemination in year period 1 in comparison to periods 2 and 3 were respectively 10.6%, 13.3% higher. Average insemination per conception in unit one and two was 2.22 and 2.38 respectively, and the difference was statistically significant. Odds ratio estimation for herd unit showed that chance of being pregnant after the first insemination in unit 1 was 15.4% higher than unit 2. Results indicate the influence of environmental and management factors on number of services needed for a cow to be conceived which by improving them reproductive efficiency will increase and pregnancy cost will decrease.

In order to evaluate efficiency of repellent substances for honey bee protection in poison’s environments, an experiment was carried out with molasses as a repellent. In all treatments of this experiment, were used 400 liters of water, 3 liters of phosalon and different concentration of molasses (including 0, 5, 7.5, 10, 12.5 and 15 liters/hectare). For evaluation the effect of molasses repellency in field condition, insect pollinators were collected 3, 8, 24, 72 hours and 7 days after spraying. Numbers of honey bees in each plot were counted separately. This research was done in spilt plot design with six treatment, five replicate and five sampling time. The result showed that significant differences between treatments in different times and also between mean of treatments in all of the times (P<0.01). Based on the obtained results average of honeybee collected in all of the time in the treatment of 15 and 12.5 liters per hectare were significantly higher than other treatments. Repellency effect of 15 liters molasses per hectare was significantly higher than other treatments three and eight hours after treatment. So, application of 15 liters molasses per hectare was recommended in chemical times.