نشریه پژوهش های علوم دامی
سال بیست و پنجم شماره 1 (بهار 1394)

Various stages of processing, storage and cryopreservation of semen, reduce frozen-thawed sperm quality due to physiological and chemical stress on the sperm membrane, decreasing sperm quality. To overcome this problem, utilization of antioxidants can play an important role. The purpose of this study is to investigate the effect of Origanum Vulgare extract as a natural antioxidant on microscopic and biochemical parameters of frozen-thawed Holstein bull sperms. In this study, semen samples were collected from three mature Holstein bulls twice a week using artificial vagina and ejaculates were pooled in order to eliminate the individual effects of bulls. Different levels of Origanum Vulgare ethanol extract (2, 4, 8, 12, 16 and 20 ml in 100 ml of diluents solution) were added to diluents based on egg yolk-citrate. Following cooling and equilibration stage of semen samples, the samples were exposed to nitrogen vapor to be frozen and stored in liquid nitrogen until evaluation. Motility, viability, membrane integrity and the lipid peroxidation parameters of the samples were evaluated after thawing, using CASA system, Eosin-Nigrosin staining, hypo osmotic swelling test and measuring malondialdehyde concentration, respectively. The addition of 4 ml/dl of Origanum Vulgare extract improved motility, viability and plasma membrane integrity parameters of spermatozoa significantly and reduced the lipid peroxidation as well compared to the control group, following freeze-thawing process (P< 0/05). our study confirms the positive effectiveness of adding 4 mL/dL Origanum Vulgare on quality of cryopreserved bull sperm.

The use of antioxidants can improve sperm quality after freeze/thawing process. The aim of the present study was to investigate the effect of Satureja Sahendica alcoholic extract on the quality of Holstein bull sperm after cryopreservation. In this study, three matured bulls, aging 5-6 years old were used. Semen samples were collected twice a week, using an artificial vagina. Semen samples were pooled after each sampling. Experimental treatments included seven levels of Satureja Sahendica ethanol extracts (0, 2, 4, 8, 12, 16, and 20 mL/dL) which diluted with citrate-egg yolk diluents containing. Then, samples were frozen and transferred to liquid nitrogen tanks for three weeks. Thereafter and after thawing and incubation for 5 min, sperm quality parameters including motility, viability, membrane integrity and lipid peroxidation were evaluated. The level of 4 mL/dL Satureja Sahendica extract significantly improved some parameters including motility, viability and plasma membrane integrity compared to control (P<0.05). The MDA concentration was lower by inclusion of 2 and 4 mL/dL extract compared to the control group, but this reduction was not significant. The level of 4 ml/dl alcoholic extraction of Satureja Sahendica has to somewhat positive effect on nominated parameters.

The use of modern technology in production units is one of the main factors of improving input productivity in livestock sub-sector. So the main objective of this research is analyzing the trend and technical change biases in Iran’s livestock using cost duality theory. METODS: The approach given in the duality theory is found useful in estimating the structure of input demand under changing input prices and technology conditions. Applying SURE method, a Translog cost function with cost share equations estimated using panel data from 24 provinces of Iran for the period 1980-2000. The results showed that the rate of technical change was about -0.312 percent during the studied period, which means that the rate of cost changes of production units, has been decreased. In addition, technical change in livestock industry was feed-using, labor-saving and energy-saving biases. COUNCLOSIONS: The finding does indicate, Increasing original cows and using artificial insemination as symbols of technical change, causes decrease in production cost and improve profitability of milk production.

Abortion and stillbirth are the effective reproductive factors that affect dairy farm profitability. The present study was designed to investigate some metabolic and pathophysiologic factors affecting abortion and stillbirth in Holstein dairy cows. Samples were collected from 43 Holstein dairy cows. Five early postpartum cows were used as stillbirth control group and five of 5 to 7-month-pregnant cows with no history of abortion were enrolled as abortion control group. Then differential blood cell counting, measurement of thyroid hormones concentrations and activities of hepatic enzymes including SGOT and SGPT were assayed on cows blood samples. In addition, microbial culturing of abomasum contents, ELISA test on brain tissue and ventricular fluid, measurement of liver glycogen concentration and histological evaluation of liver were performed on the dead calves. The results showed that the T3 to T4 ratio decreased in each group in comparison with their own controls (P<0.01). Furthermore, SGOT and SGPT activities in the plasma of both abortion and stillbirth groups were lower than their respective control groups (P<0.01). The highest neutrophils to lymphocytes ratio were observed in cows with dead born calves (P<0.001). Also, the hematocrit percent, RBC count and hemoglobin concentration increased in stillbirth cows compared with their control group (P<0.001). Liver consistency was better in aborted calves than stillborn ones, but liver glycogen concentration in dead born calves was higher (P<0.05). Microbial analysis showed that the 20.12% of aborted or dead born calves had bovine virus diarrhea in their brain tissue, but antibody titration of Neospora was not positive in any calves. The present results indicated that decreases in T3 to T4 ratio and SGOT and SGPT activities in the plasma of pregnant cows may be appropriate to evaluate the possibility of abortion or stillbirth. It seems that the presence of infectious agents has still a main role in the incidence of abortion and stillbirth, so diseases control by increasing the hygiene level and continues vaccination is so necessary.

Use of acetic acid, as a feed additive, improved broiler chickens performance via modifying intestinal microflora. Experiment was conducted to test the possibility of replacing antibiotic growth promoters with acetic acid. This study was performed by using 144 broiler day-old chicks. Birds were split into four groups and each group divided into three subgroups (replicates) which contained 12 chicks at 6 days. The amount of 3 mg/Kg lincomycin hydrochloride (An), zero (AA0), 0.7 (AA0.7) and 1.4% (AA1.4) acetic acid were added to diet of each group. At 18, 28 and 38 day, one bird of each subgroup was slaughtered and its ileosecal contents were picked. CFU/g of Coliforms, E. coli and lactobacillus of samples were determined. The lowest of feed intake (104.91 and 104.90, respectively), the highest of daily gain weight (60.97 and 61.01, respectively) and the lowest of feed conversion ratio (1.72 and 1.72, respectively) were achieved by AA0.7 and AA1.4 at the entire period (P<0.05). CFU/g of E.coli was lower in AA1.4 (5.26 and 5.40) than AA0 (6.32 and 6.45) and An (5.73 and 5.60; P<0.05) at 28 and 38 day. CFU/g of lactobacillus was lower in AA0 (6.06) than AA0.7 (6.71) and AA1.4 (6.70) at 28 day (P<0.05) and there was no difference between AA0 and An (6.49; P>0.05). CFU/g of lactobacillus was lowest in AA0 (6.14; P<0.05) and there was no difference among other treatments at 38 day (P>0.05). Due to improved food intake, daily gain weight, feed conserve ratio, CFU/g of intestinal harmful and helpful bacteria, replacement of lincomycin with acetic acid in the diet of broiler chickens is possible.

Supplementation of exogenous enzyme can improve mtabolisable energy of broiler chicken diets. This study was conducted to evaluate the effects of supplementation of exogenous enzyme on apparent DM and CP metabolizability, apparent N retention and improvement of AMEn of broiler chicken diets. A total of 200, one day old male broiler chicks were randomly assigned in completely randomized design, as 4×2×3 factorial arrangement (4×3×2) with 4 ME levels (2750, 2850, 2950 and 3050 kcal/kg) supplemented with 2 levels (0 and 450 mg/kg of diet) of an exogenous enzyme, Natuzyme –P, in diets of broilers on apparent DM metabolizability, apparent N retention and AMEn improvement over the starter, grower and finisher phases of growth. The apparent DM metabolizability of diets was increased by increasing AMEn levels (P<0001) and enzyme addition increased DM metabolizabilityby as much as 1.8 percent (P< 0.0002).The apparent N retention was increased significantly with increasing ME levels (P< 0.001). Enzyme supplementation improved apparent N retention of diets as much as 2.63 percent (P< 0.0001). The values of AMEn were improved by the main effects of ME levels and enzyme addition (P< 0.0001, P< 0.0027). Enzyme supplementation increased mean value of AMEn as much as 52 kcal/kg. Apparent N retention (P<0.0001) and apparent DM metabolizability (P<0.0007) was affected significantly by the main effect of phase growth and the highest values of apparent N retention and apparent DM metabolizability was found in grower and starter phases of growth, respectively. Two and three-way interaction effects of enzyme supplementation, ME levels and growth phase was not significant on AMEn improvement, apparent DM metabolizability and apparent N retention. Enzyme supplementation in corn-soybean meal based diet improved apparent DM metabolizability, apparent N retention and AMEn values.

Note that the chicken has an importance role in household food needs and many investments come into this industry. Therefore, attention to price Factors and chicken prices formation process can increase efficiency and resource allocation. This study investigate the input prices shocks of "one-day chicken", corn and soybean on the price of slaughtered chicken. whit using the Markov-Switching AR model based on weekly price data from 2008 through 2012. Result shows that price of poultry is a non-linear model, and the inputs of one-day chicken, soybean and corn are entirely effective on it. Moreover, the stability probability in the increase in poultry price regime is more than others.

Starch source in diets containing unsaturated fatty acids influence plasma fatty acid profile of lactating cows. This experiment was conducted to investigate the effects of different starch sources including corn grain, wheat grain, barley grain and potato in diets contacting whole cottonseed as a source of unsaturated fatty acids on plasma fatty acid profiles, dry matter intake and milk production and composition of lactating Holstein cows. In this experiment, eight multiparous Holstein cows with 83 ± 9 days in milk, 33 ± 3 kg milk production and 683 ± 31 kg of body weight were used in a repeated 4 × 4 Latin square design with 4 diets and 4 periods. Experimental diets were consisted of diet containing 25.20 % wheat grain, diet containing 26 % barley grain, diet containing 25 % corn grain and diet containing 25 % potato on dry matter basis. Dry matter intake, milk production and composition and plasma fatty acids profile were measured. Plasma concentration of 18:2 cis-9 cis-12 and total unsaturated fatty acids were higher in cows fed diet contacting wheat or barley compared to those fed corn or potato. Cows fed diet containing potato had the lowest daily raw milk yield, 4% fat corrected milk or energy corrected milk production. Milk fat percentage was higher in cows fed corn containing diet compared to other diets. Dry matter intake and concentration of milk protein and lactose were not affected by the experimental diets. According to these results, wheat and barley starch compared to corn and potato starch increased plasma concentration of total unsaturated fatty acids of lactating cows that can improve fatty acids profile of ruminant milk and tissue.

Estimation of genetic parameters of economic important traits are necessary for determining breeding goal and selection index. In present study, the genetic parameters of average daily gain from birth to weaning (ADGa), from weaning to 6 month of age (ADGb) and from 6 to 9 month of age (ADGc) and Kleiber ratio at weaning (KRa), at 6 month of age (KRb) and at 9 month of age (KRc) were estimated. The data set included 12701 records of rural flocks under supervision of Ghezel sheep breeding station located in Western Azerbaijan province and collected over the period from 1994 to 2009 were analysed by Restricted Maximum Likelihood (REML) procedure using WOMBAT software. Fixed effect of Herd - year of birth (HY) was significant on all traits. Effect of sex was significant on all traits except for KRa and effect of litter size was significant for all traits except for KRb. Effect of dam age was significant on ADGc, KRb, only. Model 1 (contains direct additive genetic effect) was the best model for ADGc and KRc and model 7 (contains direct additive genetic and maternal common environmental effects) was the best model for the other traits. Direct heritability of the ADGa, ADGb, ADGc, KRa, KRb and KRc based on the best model were 0.27, 0.18, 0.14, 0.22, 0.13 and 0.16, respectively. The proportion of maternal common environmental variance to phenotypic variance (c2) for ADGa, ADGb, KRa and KRb were 0.52, 0.16, 0.52 and 0.19, respectively. Direct heritability of Average Daily Gain and Kleiber ratio in studied rural flocks were moderate. Therefore selection specially based on KRa will be effective for these traits. Moreover, including maternal common environmental effect in animal models for accurate estimation of direct heritability in this breed is recommendable.

Including plant oils rich in unsaturated fatty acids in lactating cow diets can be used as a nutritional strategy to alter milk fatty acid composition for long-term human health. Effects of dietary plant oils rich in 18:2n-6 (POLA) on milk fatty acid (FA) composition in lactating cows, using meta-analysis and meta-regression approach were evaluated. Twenty experiments containing 27 comparisons between treatment and control groups, which met the selection criteria, were used. Two levels of supplementing POLA were evaluated: ≤ and > 30 g/kg diet DM. The POLA, at both level, reduced relative proportions of 6:0–16:0, enhanced 18:0, cis (Δ9–12, and 15) and trans 18:1 (Δ6−14), 18:2n-6, cis-9,trans-11 CLA, and trans-10,cis-12 CLA, whereas approximately 20 g/kg DM oil supplementation had no effect on 4:0 and 18:3n-3 concentrations in milk fat. Results of meta-regression showed that dietary 18:2n-6 content explained more than 55% of variation in results of 8:0–15:0. Dietary total FA content differences, grain level of basal diets, and parity were the sources of heterogeneity in milk cis-9 18:1. Milk trans-11 18:1 increased with increased dietary 18:2n-6 content and forage level of basal diets. Safflower oil > sunflower oil > corn oil > soybean oil > cottonseed oil induced higher standardized mean difference of milk 18:2n-6, trans-10, cis-12 CLA and 18:0 content. Feeding POLA lowered milk saturated FA and increased trans, monounsaturated and polyunsaturated FA.

Estimation of genetic parameters is of central importance as an animal breeding is planed and monitored. This study aimed to genetically analysis of peak milk yield (PMY) and peak time (PT) traits. A total of 130,668 test day milk records belonging to 15,183 first parity Holstein cows from 131 dairy herds of Razavi Khorasan during calving year 2000-2009 were used. For computing PMY and PT, estimated parameters of Wilmink's exponential function were applied. The function parameters were estimated using SAS software. Additive genetic, environmental variance components as well as heritability of the traits were estimated through a single trait animal model using DMU program. Genetic trend was estimated based upon a weighted linear regression of average predicted breeding value on calving year. Heritability of PMY and PT were found to be 0.17±0.018 and 0.051±0.011, respectively. A negative annual and significant (P<0.05) genetic trend (-0.014 kg) was revealed for PMY. For PT, genetic trend was 0.006 day per year and not statistically significant. with respect to the heritability of PY trait it could be utilized in genetic selection of the cows in Razavi Khorasan dairy herds.

Estrus synchronization is a valuable technique in control of reproductive function in ewe. The aim of this study was to determine the status of estrus incidence and hormone profiles in blood serum of Arabic ewes synchronized using the long and short periods of CIDR in non-breeding season. In non-breeding season, a total of 58 Arabic ewes aged 2-5 years old (average of BW 46 kg) and non pregnant in a completely randomized design were assigned to three experimental groups: 1- control (no treatment), 2- short-term (6 days) and 3- long-term (14 days) treatments with vaginal CIDR. Immediately after removing the CIDR, 600 IU of PMSG was injected intra muscle. In the CIDR treatments, estrogen and progesterone concentrations of blood serum were measured immediately before of CIDR insertion, three days after CIDR insertion, one day after CIDR removal and 50 days after mating. In order to heat detection and mating, one healthy and fertile Arabic ram was introduced to every 5 ewes. The interval to estrus after CIDR removal in short and long term treatments, were 51.02 and 34.74 hours, respectively (P<0.01). Occurrence of estrus in short-term (88.8%) and long term (95.2%) treatments of CIDR was higher than control (5.26%) (P<0.01), but this difference between CIDR treatments was not significant (P> 0.05). One day after CIDR removal and 50 days after mating, estrogen concentration of blood serum was significantly higher in long-term than the short-term CIDR treatment (P<0.01). There was no significant difference in blood serum progesterone level between treatments in all times (P>0.05). The concentrations of these hormones in various periods of short and long term treatments of CIDR were in fluctuant. The use of short term (6 days) CIDR has the appropriate estrus occurrence and reproductive function in non breeding season of Arabic ewes.

Silybum marianum and purslane seed contains many compounds that can be useful for laying hens. This experiment was conducted to study the effect of different levels of purslane and milk thistle seed into the diet of laying hens on performance, some egg quality traits and serum and egg yolk lipids. A 3 × 3 factorial experiment with three levels of purslane seed (0, 1 and 2%) and three levels of milk thistle seed (0, 1 and 2%) in the diet in a completely randomized design with 288 laying hens Hy-Line W-36 who were reared in cages, from 32 to 42 weeks with 9 treatments, 4 replicates and 8 hens in each replicate. Supplementation of 1% purslane seed and 2% milk thistle seed on diets, significantly increased egg weight (P<0.05). Also the use of 2% purslane seed significantly increased the egg production and egg mass of laying hens (P<0.05). The best feed conversion ratio obtained in hens receiving 2% purslane and 0% milk thistle which was significant compared to the control treatment (P<0.05). Shell thickness and haugh unit significantly improved by consumption of 2% milk thistle seed (P<0.05). Different levels of purslane seed and milk thistle, reduce the cholesterol and triglyceride in blood serum and yolk, but were not significant. The levels of blood HDL of birds showed a significant increase by adding 2% purslane seed (P<0.05). The results of this study suggest that the levels of 2 percent milk thistle and purslane seeds have beneficial effects on performance factors and level of 2 percent milk thistle seed improves egg quality traits in laying hens.

Microbial contamination and somatic cells are account as two important factors in reducing the shelf life and entire quality of raw and pasteurized milk. This study was carried out on the seasonal variation of milk microbial and somatic cell counts. Six industrial and traditional dairy farms from Hamedan province were sampled monthly for a period of one year. Records of somatic cell and bacterial count of samples were analyzed by using different statistical methods in SAS software. Least square mean (±SE) somatic cell count (cells per ml×1000) and total microbial was 325.10(±¬13.20) and 5287.03(±¬261.23), respectively. Differences in microbial count in industrial and traditional farms was significant (P<0.0001). Seasonal changes in total count was significant (P<0.0002) and the effect herd nested in farming system was significant (P<0.0001) as well. Also there were significant difference in farming system and herd on somatic cell counts (P<0.0001). Although industrial dairy farms had lower total count than traditional dairy farms, the somatic cell counts were higher and need to be more investigated on annually herd combination, dry-off time and cutting strategy of low producing and infertile dairy cows.

The field of research was animal feed production, especially in sheep feeding. The aim of this study was determination of nutrient composition and DM, OM and CP degradation parameters of grape and lime pomaces by in situ technique. First, nutrient composition of pomaces and alfalfa (observer) including CP, PC, OM, NDF, Ash, TT and EE were determined by AOAC method. The DM, OM and CP degradability was obtained after (0, 4, 8, 16, 24, 48, 72 and 96 hour) by using 3 fistulated Talesh male cows. This experiment was analyzed with completely randomized block design. The OM, NDF and lignin of grape pomace were 96.3, 57.6 and 34.4 % respectively and CP, Fat and NFC of lime pomace were 9.2, 7.7 and 54.2 % respectively. The DM, OM and CP degradation (in 24 hour incubation) of the grape were 36.3, 39.6, 48.8 respectively and lime pomaces were 80.5, 82.0, 89.5 respectively (%DM). Also, DUP and MP (on maintenance) for grape, lime pomaces and alfalfa were 34.3, 3.0, 13.4 and 56.5, 47.7, 81.2 (g/Kg) respectively. Based on the nutrient composition, degradation DM, OM and CP parameters and MP of the experimental pomaces, they may be used as new sources of non-forages fiber and energy (in order of grape and lime pomaces) in ruminants feeding.