JOURNAL OF RUMINANT RESEARCH
Year:2016 | Volume:3 | Issue:4|Papers Count:10

Background and objectives: In this study, the relationships between live body weight at slaughter, carcass characteristics (weights of hot carcass, cold carcass, cold half-carcass, lean meat, fat, bone and fat-tail) and body measurements (body length, chest girth, hip width and shoulder width) were investigated in Lori-Bakhtiari sheep. Two methods of linear regression and artificial neural network (ANN) in prediction of live weight and carcass characteristics were compared.Materials and methods: The data of 58 male lambs were collected at the Breeding Station of Lori-Bakhtiari sheep in Shahrekord city of Chaharmahal and Bakhtiari province, Iran. The lambs were weaned at 90±5 days of age and were fattened in three groups of 60, 80 and 100 days. At the end of fattening period, body measurements and after slaughtering and skinning, all carcass characteristics were measured. A total of 696 records were used for prediction of carcass characteristics by using regression models and ANN. The possibility of predicting carcass characteristics and live weight at slaughter through body measurements was evaluated by choosing the most suitable regression model based on the value of the determination coefficient. The selective regression models also were fitted by artificial neural network then; these two methods were compared based on the value of the determination coefficient and the mean square errors.Results: The estimated phenotypic correlation coefficients between carcass characteristics and live weight at slaughter were generally positive and relatively high (0.58 to 0.99). The phenotypic correlation coefficients between carcass characteristics and body measurements were estimated between 0.29 and 0.69.Between all body measurements, the highest correlations are observed between chest girth and carcass characteristics and live body weight. Based on relatively high phenotypic correlation coefficients in this research, prediction of carcass characteristics and live body weight can be possible with high accuracy by using body measurements. The results show that, to prediction of live body weight of Lori-Bakhtiari male lambs, body length, chest girth and hip width must be included in the regression model to obtain an accuracy of 79 percent. The regression equation including live body weight and heart girth could predict hot carcass and cold carcass weights with an accuracy of 97 and 96 percent, respectively. Live body weight alone explains the 94 and 72 percent of the variation of half-carcass and fat-tail weight, respectively. Moreover, the results show that the accuracy of ANN model for prediction of some carcass traits was more than regression models.Conclusion: Based on results of this research, prediction of carcass characteristics and live weight is possible with relatively high accuracy by using some phenotypic body measurements. Also, results indicate that the artificial neural network technique was much better capable of predicting weight and carcass traits in Lori-Bakhtiari sheep compared to linear regression equations. The results of this study can be useful due to the importance of carcass traits in determination of genetic potential and regulation of animal breeding programs for high meat production.

Background and objectives: This study was conducted to investigate association between prolactin gene polymorphism and milk yield of Shirvan Kurdi sheep. Prolactin is a lactogenic hormone that plays a significant role in milk production; its depletion in sheep provokes a severe reduction of milk secretion suggesting that prolactin is a functional candidate gene that could contribute to variations in milk yield. An Investigation indicated that polymorphism prolactin gene in Chios sheep. They identified a 23-bp indel (insertion or deletion) in the 213 region and found that the B allele is the result of a 23-bp deletion in a allele. They also reported A and B allele with the frequencies of 0.71 and 0.29, respectively and found that the B allele may be associated with higher milk yield.The present study investigated the association between polymorphisms in prolactin gene and daily milk yield records of Kurdi ewes in Hossien Abad Kurdi sheep breeding station.Materials and methods: In this study, blood samples were collected randomly from 100 milking Kurdi ewes in Hossien Abad Kurdi sheep breeding station. Milking was carried out by hand combined with lamb suckling at 14 days intervals starting from May to Agust 2012. Allele and genotype frequencies, chi-square test and the goodness of fit test for Hardy-Weinberg equilibrium were calculated with Pop Gene V 1.31 software. Statistical Analysis was performed using INBREED and the MIXED procedures of SAS to estimate the association of genotypes with milk production.Results: A 23-bp indel (insertion or deletion) was identified in prolactin gene by PCR. A mixed model was used to investigate the association of prolactin gene with test day milk yield. AA genotype had the highest genotype frequency in the studied population (0.60). A and B allele frequencies were 0.765 and 0.235, respectively. Results indicated that there was no significant association between prolactin gene polymorphism and milk yield in the studied population.Conclusion: In the present study, no genotype was identified to be better than the others and there was no significant association between prolactin gene polymorphism and milk yield.

Background and Objectives: Conjugated linoleic acid (CLA) is a generic term for a group of 18-carbon fatty acids with a conjugated double bond that influence a range of biological processes. Pro-inflamatory cytokines have been shown to contribute in insulin resistance process and CLA can inhibit some pro-inflamatory cytokines production. The effect of CLA on milk fat depression caused uses it as a nutritional strategy to improve negative energy of dairy cows. The aim of this study was to evaluate glucose tolerance test and blood glucose changes of dairy cows fed conjugated linoleic acid (CLA) from -21 to +21 or -42 days (d) relative to parturition.Materials and Methods: Seventy five multiparous dairy cows were allocated to one of four treatments: feeding palm oil (75 g/d) from -21 d to+21 d (C21) or +42 d (C42) relative to parturition, feeding rumen protected CLA (75 g/d) from -21 d to +21 d (CLA21) or+42 d (CLA42) relative to parturition. Rumen protected CLA provided 7.5 g/d each of trans -10, cis -12 CLA and cis -9, trans -11 isomers. Glucose tolerance tests (GTT) was carried out on five cows from each group by infusing 0.25 g/kg of BW of glucose (iv) through milk vein at 14 and 30 d after parturition. Blood samples were collected from the milk vein of opposite side of glucose infusion at -20, -10, 0, 5, 10, 20, 30, 40, 60, 80, 100 and 120 minutes (min) relative to infusion and plasma glucose level determined after centrifuge. Area under curve at 60 and 120 min, glucose clearance rate and time to reach half concentration of glucose were calculated as GTT indices. To evaluate blood glucose and insulin changes after parturition blood samples were taken via coccygeal venipuncture from a subsample of 8 cows per treatment at just after calving and 10, 21 and 42 d postpartum. Milk yield was recorded daily and milk samples to determine milk constitutes were taken weekly.Results: Feeding rumen protected CLA had no significant effects on GTT indices. Differences between GTT indices were significant at 14 and 30 d postpartum (P˂0.05) that was indicative of improvement of insulin sensitivity as days in milk increased. Blood glucose concentration was higher at parturition and 10 d after parturition in CLA fed cows than palm fed cows while blood insulin concentrations were the same among treatments (P˂0.05). CLA fed cows had less milk fat content and yield than palm fat fed cows (P˂0.05). Feeding rumen protected CLA during transition period increased milk yield during early lactation (P˂0.05). Extending rumen protected CLA or palm fat feeding to 42 d postpartum couldn’t increase milk yield compared to 21 d postpartum.Conclusion: Results of this experiment showed that adding CLA supplementation to dairy cows ration during transition period resulted in increased blood glucose concentration at early lactation and increased milk yield without any negative effects on GTT indices as indicators of insulin resistance situation.

Background and objectives: The beneficial effects of adding supplemental polyunsaturated fats including omega-6 and omega-3 sources to the diet on reproductive performance of livestock have been shown in many studies. On the other hand, low performance of artificial insemination is a serious problem to perform genetic improvement projects in sheep. Special effect of adding fish oil as an omega-3 source to flushing diet on reproductive efficiency of ewes after laparoscopic artificial insemination has not been investigated. The aim of this study was to investigate the effect of supplementing flushing diet with fish oil on reproductive efficiency of Chaal ewes after laparoscopic artificial insemination.Materials and methods: One hundred eleven of non-lactating and non-pregnant Chaal ewes, were divided into three experimental groups based on flushing diets: (1) negative control group (C-), fed the flushing diet without any supplemental fat, (2) positive control group (C+), fed the flushing diet containing 3.5% supplemental hydrogenated palm oil (palm fat powder) and (3) fish oil group (FO), fed flushing diet containing 3.5% fish oil. Estrus synchronization of ewes performed using progesterone sponges for 13 days. Twenty to 48 hours after sponge removal, the rate of estrus recorded using rams with aprons and marking harnesses. Forty eight hours after sponge removal, artificial insemination was performed with the laparoscopic approach. Fifteen days after artificial insemination, to determine estrus non return rate and for mating of non-pregnant ewes, the rams with marking harnesses were introduced into the flock. Forty days after insemination, pregnancy diagnosis was performed by ultrasonography. At the time of lambing, number and weight of born lambs and three months later, the number and weight of weaned lambs were recorded for each ewe in experiment and using them reproductive traits including pregnancy, parturition, abortion, stillbirth, barren and multiple lambing rates, prolificacy, fecundity, born lamb crop, lamb viability, weaning rate and weaned lamb crop (ewe productivity) were calculated.Results: Adding fish oil to flushing diet significantly increased the weaning rate from laparoscopic artificial insemination and accumulated weaning rate from artificial insemination and natural mating (P<0.05). The improved weaning rate for ewes fed fish oil resulted by more multiple lambing rate and prolificacy in this group in comparison with two other groups, because pregnancy rates in three groups were not affected by flushing diets (P>0.05). In the group fed hydrogenated palm oil, lamb viability until weaning time was significantly (P<0.05) lower than two other groups.Conclusion: In the programs of artificial insemination and synchronized natural mating of sheep, adding fish oil to flushing diet can improve reproductive performance. It is recommended that avoid using hydrogenated palm oil in flushing diet of sheep.

Background and objectives: This study evaluated the effects of seasonal change and diet on milk production, milk composition and related indices from 5 industrial dairy farms in Mashhad.Materials and methods: Samples in summer period (in 2014) and winter period (in 2015) were taken on each farm. Meteorological data were obtained from the Northeast Regional Climate Center of Iran, Mashhad. Dairy cows were fed with 2 diets, control diet and 10% flaxseed diet. In each farm, animals were divided into 3 groups based on their days in milk (early, middle and late). Diets were provided as TMR. Dry matter intake, daily milk yield, milk fat, milk protein, milk lactose and solids in milk were measured. Milk fat extraction and fatty acid separation were determined.Results: Increasing temperature-humidity index (THI) had decreased dry matter intake in summer (THI³72) against winter period (THI£72; 21.8 vs.24.0 kg DM d-1, respectively). Modification dry matter intake decreased milk yield and milk protein, but milk fat tended to increase. In addition, we observed the highest fat-to-protein ratio in winter (1.39 vs. 1.28). Milk yield, polyunsaturated fatty acids (PUFA), linolenic acids and monounsaturated fatty acids (MUFA) and linoleic acids for the cows were fed 10% flaxseed was significantly higher than for those fed control diet, but percentage of milk fat was significantly reduced when diets were supplemented with flaxseed. Feeding diets of flaxseed had no effect on dry matter intake, milk protein percentage, lactose and milk solids compared with control diet. The canonical correlation analysis of indices demonstrated that daily milk yield was negatively correlated with milk protein but no significant relationship was observed between daily milk yield and the other indices. Here, we found that milk solids was significantly correlated with milk fat (r=0.795), milk protein (r=0.770), and milk lactose (r=0.477). Moreover, concentration of unsaturated fatty acids milk (18 carbons) was negatively correlated with milk fat.Conclusion: The experiment demonstrated that the fed of flaxseed in winter was effective at increasing fat-to-protein ratio, indicating that cows mostly utilize their body fat. These results clearly demonstrate the possibility for sustainable production of organic omega-3 milk up to 2.3 times higher than typical levels in milk fat. Furthermore, it is necessary to investigate the factors that affect raw milk composition, which may improve the quality and yield of milk through temperate environmental conditions and management of nutritional supplementation.

Background and objectives: Whole barley kernel because of its intact pericarp is resistant to bacterial attachment in the rumen and digestion by ruminants. Therfore, barley processing is required to make its endosperm, encased within indigestible pericarp and hull layers, accessible to the microbial population in the rumen. This study was carried out to evaluate the effects of processing method (grinding vs. steam flaking) using completely randomized design and to investigate the impacts of steaming duration, roller setting, and interaction between steaming duration and roller setting on ruminal degradability of barley grain dry and organic matter in a 3 x 2 completely randomized factorial design.Materials and methods: Five grams (DM basis) of processed barley, ground barley using a hammer mill with a standard screen size of 3 mm (GB) or steam-flaked barley (SFB) using 3 steaming times including of 35, 45 or 55 min. and 2 roller setting distances of 0.3 or 0.4 mm for each steaming time, were weighed into bags (10×20 cm) made of polyester (pore size, 50 m). Triplicate nylon bags were placed in the rumen of a non-lactating Holstein dairy cow for 0, 2, 4, 8, 16, 24, and 48 h, respectively, for each sample. The incubation was repeated three times. Residues of dry matter (DM) and organic matter (OM) per incubation time were analyzed using SAS software.Results: Processing method changed the density of GB (616 g/L), SFB (285 g/L on average) compared to whole barley grain density (684 g/L). Increasing the extent of barley flaking decreased the density from 390 to 180 g/L, and kernel thickness from 1.5 to 1.0 mm. Grinding of barley versus steam-flaking on average increased DM and OM disappearance (%) and raised (P<0.01) the washable fraction (28.6 vs. 21.6%), degradation rate of potentially degradable fraction (0.10 vs. 0.05/h), and effective degradability (60.4 vs. 47.5%); whereas it reduced (P<0.01) the potentially degradable fraction (51.7 vs. 56.0%), and undergrad able fraction (19.7 vs. 22.5%) of DM and increased (P<0.01) the washable fraction (28.3 vs. 21.4%), degradation rate of potentially degradable fraction (0.10 vs. 0.05/h), and effective degradability (60.6 vs. 47.6%); whereas it reduced (P<0.01) the potentially degradable fraction (52.6 vs. 56.5%), and undegradable fraction (19.1 vs. 22.1%) of OM (P<0.01). Increasing the steaming time and decreasing the distance of roller setting (to comparison the distance of rollers, 0.4 vs.0.3 mm) on average increased DM and OM disappearance (%) but decreased the potentially degradable fraction (62.6 vs. 49.4%), and increased the washable fraction (17.8 vs. 25.3%), undegradable fraction (19.7 vs. 25.3%), degradation rate of potentially degradable fraction (0.05 vs. 0.06/h), and effective degradability (44.1 vs. 50.9%) of DM and decreased the potentially degradable fraction (62.9 vs. 50.1%), and increased the washable fraction (17.7 vs. 25.1%), undegradable fraction (19.5 vs. 24.9%), degradation rate of potentially degradable fraction (0.05 vs. 0.06/h), and effective degradability (44.2 vs. 51.0%) of OM for SFB (P<0.05).Conclusion: Results of this study showed that processing method could change barley grain density, particle size and its distribution on sieves. Grinding versus flaking increased the effective degradability of grain DM and OM. Ruminal DM and OM degradability of barley grain could be manipulated by varying the duration of steaming and the distance of roller setting.

Background and objectives: Soil pollution and accumulation of heavy metals in plants and crops in industrial areas is one of the most important environmental threats for plants, animals and humans' life. Cadmium (Cd) is a hazardous heavy metal with a long biological half-life and low rate of elimination from the body. The aim of this study was to determine the effects of long term cadmium uptake on performance and several serum biochemical parameters in lambs fed on a growing diet.Materials and methods: Ten male Mehraban lambs of 8-9 months old were randomly assigned to two dietary groups as control (basal diet) and treatment (basal diet+100 mg Cd/kg DM as CdCl2). The lambs were fed twice daily at early morning and evening, and blood samples were collected from jugular vein on days 0, 35 and 70 before morning feeding using vacutainer tubes. Sample sera were separated and stored at -20°c until analysed. The serum biochemical parameters including Cd, urea nitrogen (SUN), creatinine, sodium, total protein (TP), albumin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), Gamma glutamyl transferase (GGT), creatine phosphokinase (CPK), alkaline phosphatase (ALP) and its bone specific isoenzyme (BALP) were measured. Serum biochemical parameters were analyzed by an auto-analyzer using correspondences Pars Azmoon kit according manufacturer manuals. Sodium was measured using flame photometry method. Statistical analysis was carried out using Duncan's multiple range tests.Results: Average daily weight gain and dry matter intake were lower in the Cd group (P<0.05). In day 70, Albumin; in days 35 and 70, ALP and BALP decreased in the Cd receiving compared with the control group (P<0.05). CPK was increased in Cd compared with control group in days 35 and 70 (P<0.05).Conclusion: The results of this study showed that ingestion of Cd at level of 100 mg /kg DM has not been considerable toxic effect on growing lambs during 70 days.

Background and objectives: Carcass characteristics and meat quality are important criteria for customer when it comes to making purchasing decisions. Effects of adding direct-fed microbial on ruminants meat quality have never been investigated, given that probiotics ability to manipulate fatty acid absorption and lipid metabolism in body have been proven in many studies. The aims of this study were, therefore, to evaluate the effects of a bacterial probiotic on carcass and meat quality attributes in Morkhoz kids, as an important indigenous breed of our country.Materials and methods: Experimental diet was formulated based on NRC recommendations. The study was conducted based on a completely randomized design, including two treatments and eight replicate using 16 male Morkhoz kids. Kids were fed for 119 days with experimental diet. Commercial probiotic was combination of four bacterial strains, include Lactobacillus acidophilus (2.5×107 cfu/g), L. casei (2.5×107 cfu/g), Streptococcus faecium (2.5×107 cfu/g), and Bifidobacterium thermophilum (1.0×108 cfu/g). This probiotic was fed to each kid before morning feeding (2 gr/d/kid, based on supplier recommendation). At the end of the experimental period, four kids from each treatment were slaughtered and the carcass characteristics include femur muscle to bone ratio and muscularity in the femur region, and meat quality attributed in biceps femoris muscle include physical attributes, chemical composition and fatty acid composition were determined.Results: Results showed that between femur components examined in this research only muscularity in the femur region was significantly affected by probiotic consumption. This parameter showed significantly higher value in control (non-probiotic) group. Indeed, except L* and hue angles values, commercial probiotic had no significant effect on other meat quality parameters in biceps femoris muscle include pH, drip loss, water holding capacity, cooking loss, shear force and also on its chemical composition. Examining of fatty acid composition of intramuscular fat in the biceps femoris muscle showed that the probiotic we used in this experiment did not affect any of fatty acids features include percent of saturated fatty acids, unsaturated fatty acids, mono-polyunsaturated fatty acids, total desirable fatty acids and n-6/n-3 ratio.Conclusion: In conclusion, it seems that bacterial probiotic used in this experiment won't cause a considerable change in muscle ratio in femur region and also meat quality attributes.

Background and objectives: Calving interval is sought to be substantially affected by management and environmental effects. Using intellectual algorithms of machine learning methods to investigate complex systems are growing and these algorithms could be assumed as right approach to analysis dairy cattle industry data. Artificial neural networks which are part of artificial intelligence, gain from these algorithms. The objective of this study was to find the association between productive and reproductive traits with calving interval over different course of inseminations. It was assumed that extracting this association may improve the management of this trait.Materials and methods: In this research, the productive and reproductive traits from FOKA, an agriculture and animal husbandry, associated to Isfahan Vahdat Cooperative was used. The records were calving interval (day), the length of dry off period (day), number of insemination, total milk production (kg), total fat production (kg), total protein production (kg), adjusted milk production (kg), adjusted fat production (kg) and adjusted protein production (kg). The data were due to 15465 cows in which their parturition date spanned between 1368 and 1393. The data dimensions were reduced using elimination of high level of correlation among variables and principal component analysis before undertaking artificial neural network modeling. For each insemination, we learned a neural network. We used coefficient of determination and root mean square error to investigate the efficiency of neural network. The linear and nonlinear relationship among input variables with calving interval was measured using maximal information criterion.Results: The similar values of coefficient of determination and root mean square error due to neural network in different insemination obtained which would indicated that there is almost identical associations between calving interval input variables. Higher values of root mean square error obtained in neural network which learned based upon principal component analysis of independent data than elimination one. Therefore, it was concluded that elimination approach is suitable choice in this context. The maximal information criterion showed almost an identical association between calving interval and input variables over different inseminations. In this way, days in milk and milk production showed high amount of correlation with calving interval.Conclusion: The results indicated that coefficient of determination and root mean square error of different inseminations was similar. Therefore, it is hardly expected that the association between calving interval and independent variables to be different over different inseminations. Based upon these results, it was elucidated that independent variables used in this study could fairly adequately predict the calving interval. Also, we could say that management- environmental conditions over different inseminations had minuscule effect on the associations of calving interval with independent variables.

Background and objectives: Estimates of genetic parameters for traits of economic importance in dairy cattle are necessary for implementing efficient breeding programs. Accurate heritability and correlation estimates are required to predict expected selection response and to obtain predicted breeding values using mixed model procedures. Traits related to milk, fat, and protein production, conformation, length of productive life, reproduction, workability, and health are included in breeding programs of dairy cattle in many countries to maximize improvement of a breeding goal involving traits related to income and costs. Extreme or rapid changes in environmental conditions can often be detrimental to cattle performance. The objective of this study was the genetic analysis of productive and reproductive traits of Holstein dairy cows in arid climate of Iran using multivariate animal model.Material and Methods: Data from 5403 first lactation Iranian Holsteins collected by the Animal Breeding Center of Iran during 1996 to 2009 was used for the multivariate genetic analysis of productive (milk, fat and protein yield, fat, protein percentage) and reproductive traits (length of dry period, age at first calving and calving interval). According to weather conditions, geographical location of herds and De Martonne's global classification five climate groups (arid, semiarid, Mediterranean, semi humid and humid) were identified. Provinces: Semnan, Yazd, Southern Khorasan, Ghom, Sistan and Bluchestan, Kerman were in the arid class. Variance components, breeding values and genetic and phenotypic correlations were estimated by restricted maximum likelihood method using DMU package.Genetic and phonotypic trends were computed as a linear regression of yearly means on calving year using the REG procedure of SAS 9.2.Results and Discussion: The estimated heritabilities were 0.23, 0.27, 0.28, 0.39, 0.41, 0.03, 0.05, 0.25 and 0.054 for milk, fat and protein yield, fat and protein percentage, length of dry period, age at first calving and calving interval, respectively. The range of absolute genetic correlations was varied from 0.0.01 for fat yield-length of dry days to 0.84 for milk-protein yield and absolute phenotypic correlations were from 0.01 for protein-fat yield, and age at first calving-protein percentage to 0.91 for milk-protein yield. Genetic trends (for daughters) for milk, protein yield and protein percentage were, respectively, 4.48±0.88, 0.08±0.03 kg and -0.001±0.0002 % (P<0.01). Genetic trends for other traits were not statistically significant.Conclusion: The results showed that for all traits in the study, phenotypic trend was statistically significant and favorable. For milk and protein yield of Holsteins in arid climate of Iran, the genetic trend was positive and significant.