Iranian Journal of Animal Science
Year:2018 | Volume:49 | Issue:3 |Papers Count:16

The objectives of this study were to estimate and compare the biological and economic consequences of the implementation two policies including non-optimal and optimal culling decisions. For this purpose, data were collected during 2015 and 2016 from one of large dairy herds in Isfahan province. Then using different procedure of SAS software (NLIN, MEANS, LIFETEST), the biological parameters of this herd (including the shape of Lactation curve, risk of involuntary culling and probability of pregnancy in different milk periods and month in milk after calving) were estimated. In the following, by entering the biological and financial parameters to the bio_economic model developed in DairyVIP software, the herd status was simulated in different situations. The basis for optimal and non-optimal decisions were minimizing the opportunity cost and reach the daily production of non-pregnant cows to less than 20 kg, respectively. By implementing optimal policies, the annual culling rate increased from 31. 9% to 41. 9%, which resulted in an increase of 9, 650, 000 rials in heifers purchase cost. However, an increase in the revenue from the sale of milk calves and culled cow led to 3, 390, 000 Rials an overall improvement in net annual profit by each cow. The results of this research can help to change in dairy producer's attitude toward the replacement decision.

Considering the importance of maintaining the diversity in native breeds and identification of genetic resources of the country, the genetic diversity in Azari buffaloes was evaluated using ten microsatellite markers (BoLA-DRB3, BM1818, BM1824, CSSM033, CSSM047, ILSTS017, ILSTS033, ILSTS058, ILSTS061 and ILSTS089). Hair samples were taken from 70 Azari buffaloes from three regions of the northwest of Iran including Ardabil, East Azerbaijan and West Azerbaijan provinces. Genomic DNA was extracted from the hair samples by the modified salting-out method and for DNA amplification the polymerase chain reactions for all primers were optimized. The results indicated that, in Azari buffalo population, all microsatellites loci were highly polymorphic, and they were deviated from Hardy-Weinberg equilibrium (P<0. 001) with an exception for BoLA-DRB3 locus. The average observed and expected allelic numbers were 5. 9 and 4. 72, respectively. The observed and expected heterozygosity, Polymorphic Information Content (PIC) and Shannon Index were 0. 87, 0. 75, 0. 71 and 1. 57, respectively. In conclusion, the genetic variation in Azeri buffalo population is quite high and reliable.

This research aimed to evaluate two concentrations of egg yolk inclusion rate (15% and 20%) in the semen extender of goat semen cryopreserved during breeding season. Thirty ejaculates were collected from five trained Mahabadi goats and diluted in egg yolk based extenders. The semen samples were frozen, and after thawing evaluated for seminal characteristics i. e. sperm motility and morphology, membrane and acrosome integrity, viability, apoptosis status and DNA fragmentation. The data were analyzed using GLM procedure in SAS software. There were not significant differences in total and progressive motility of sperm in 20% egg yolk extender (69. 00± 1. 69 and 52. 57± 1. 29 respectively) and 15% egg yolk extender (68. 21± 1. 69 and 52. 35± 1. 29 respectively). Moreover, sperm viability, membrane integrity, and normal sperm cells percentage in extender with 20% and 15% egg yolk were evaluated to be (83. 88± 1. 08, 72. 80± 2. 43, and 84. 31± 1. 85) and (86. 65± 1. 08, 72. 37± 2. 43, and 79. 25± 1. 85) respectively. Also, in the terms of sperm with intact acrosome and DNA fragmentation rate, no significant differences were observed in the extenders. In the apoptosis test, more live sperms were observed in the group containing 20% egg yolk compared with the one containing 15% egg yolk. To elucidate the effect of diluents used in present study on sperm fertility, further studies should be conducted in vivo.

This study was conducted to evaluate the TLR4 gene expression's pattern in ampulla and isthmus of dairy cows during the ovarian cycle. The ovarian cycle phase was determined based on the appearance, size, and color of corpus luteum and dominant follicle. The TLR4 expression was assessed in ampulla and isthmus of 40 oviducts using qRTPCR. Results showed at the pre-ovulatory phase, TLR4 gene expression in the isthmus of ipsilateral oviducts was significantly greater than that in ampulla. Also, the expression of TLR4 in ampulla and isthmus of the oviducts ipsilateral to the pre-ovulatory ovary was significantly greater than that in the ampulla and isthmus of oviducts contralateral to the post-ovulatory or mid-cycle ovaries. In general, the present study showed that, TLR4 mRNA expression was differentially influenced by the stage of the ovarian cycle, its relation to the functional ovary, and the oviductal parts (ampulla or isthmus) in bovine.

The objective of the present study was to estimate the inbreeding values using run of homozygosity and study the evolutionary trend of the effective population size (Ne) in some Asian horse breeds. A total of 99 animal samples consisting 19, 24, 18, 19 and 19 samples from AkhalTake, Arrabian, Caspian, Mongolian and Thoroughbred breeds, genotyped by Illumina SNP50K Beadchip assay were used in this study, respectively. This study has been performed in collaboration with the Equine Genetic Diversity Consortium (EGDC) project. The inbreeding values based on the run of homozygosity using FROH and next, Ne using linkage disequilibrium across 5 up to 1000 generations ago were estimated. The result of principal component analysis (PCA) indicated that all breeds will be separated from each other in the first two principal components. Average expected and observed heterozygosity for different breeds ranged 0. 278-0. 294 and 0. 278-0. 308 respectively. Estimation of inbreeding based on genomic information showed that the values are ranged between 0. 003 in Mongolian up to 0. 166 in Thoroughbreds. The Ne results showed a decreasing trend over the last 1000 generations for all breeds, with an increasing slope since about 100 generations ago. The highest historically effective population size in recent generations (5 generations ago) was found in the Arabian breed (53 heads) and the lowest for Caspian and Thoroughbred (33-34 heads) breeds. Generally, the results of this study indicated that despite a reasonable genetic variation and low inbreeding value, however, the Ne is the lowest in Caspian compared to other Asian horse breeds that designing of appropriate programs is necessary to conserve remaining purebred animals of this indigenous Iranian horse breed.

In order to investigate the effect of organic zinc (Zn) supplement in broiler chicken nutrition that reared at high stock density, this experiment was done by using 2 levels of density (10 and 16 birds/m2) and 4 levels of Zn (40, 80, 120 and 160 ppm) in a completely randomized design with 4×2 factorial arrangement. The results showed that birds with higher stocking density had lower feed intake (FI) and feed conversion ratio (FCR) compared to those in normal density from d 1-21 and birds with normal stocking density had lowest FI and FCR from d 22-42 (P<0. 05). Cecal population of Coliform decreased in normal and high stock density by increasing Zn level in the diet (P<0. 05). Apparent ileal digestibility of crude protein significantly increased by increasing the levels of Zn in the diet in normal and high stock density (P<0. 05). These data suggest that dietary supplementation of Zn significantly increased ileal digestibility of crude protein and organic matter and also, decreased cecal population of Coliform and E. coli in high and normal stocking density without affecting the performance of broilers.

The present experiment was carried out to evaluate the effect of different levels of fennel essential oil nanoemulsion (FEON) on energy and protein efficiency ratio, litter and excreta quality and welfare related parameters of broiler chickens reared under heat stress. A total of 200 day-old Ross 308 broiler chicks were assigned in a completely randomized design with 5 treatments and 4 replicates. The experimental treatments were control (basal diet with no additive), basal diet and 200 mg/kg fennel essential oil (FEO) and basal diet with 50, 100 and 200 mg/kg of FEON. The results of this experiment showed that trans-anethole, fenchone and limonene with the values of 81. 49, 7. 16 and 4. 98 percent, respectively were the main compounds of fennel essential oil. The protein and energy efficiency ratios were not affected by different experimental treatments. The excreta pH of chicks fed diet containing 200 mg/kg FEON was significantly (P≤ 0. 05) less than those of fed diets containing 50 and 100 mg/kg of FEON and the control group. The litter moisture was decreased significantly (P≤ 0. 05) by supplementation of diet with 50 mg/kg FEON when compared with control group. The hock burn and abdominal plumage scores were decreased significantly (P≤ 0. 05) in chicks fed diet containing 50 mg/kg FEON when compared with other groups. According to the results of this experiment, it seems that the utilization of FEON in heat stress condition can improve broiler welfare related parameters via decreasing the litter moisture.

This experiment was conducted to compare the effect of some poultry probiotics produced in Iran on performance parameters, economic indicators and small intestinal morphology of broilers using 500 one-day-old Ross 308 broilers in a completely randomized design with 5 treatments and 5 replicates per each treatment. The experimental treatments were: 1-basal diet (control), 2-basal diet + Bacto-Gene® probiotic, 3-basal diet + Di-Pro® probiotic, 4-basal diet + Hypro-Tect® probiotic and 5-basal diet + Probitaz® probiotic. At 24 and 41 days of age, one male broiler chick was slaughtered from each experimental unit. Orthogonal contrasts were done to compare the effect of probiotics versus control. The results of this study showed that the treatments containing probiotic had no significant effect on body weight gain and feed conversion ratio. The utilization of probiotic Hypro-Tect® resulted in significant reduction in feed consumption in whole experimental period compare to other treatments containing probiotic (P≤ 0. 05). The final body weight, European efficiency factor, economic indices and carcass percentage were not affected by experimental treatments. The utilization of probiotics had no significant effect on intestinal relative length and morphological indices of jejunum and ileum. In orthogonal contrast, the utilization of treatments containing probiotic increased feed cost as compared to control group (P<0. 05). According to the results of this study, it seems that the utilization of studied probiotics had no significant effect on performance parameters, economic indices and small intestinal morphology of broilers reared in optimal condition as compared to control group.

The present study was carried out to study different methods of heat processing on nutritional value of vetch seed. Vetch seed was processed by steam flaking, roasting and microwaving. Dry matter degradability was determined using nylon bags at 0, 2, 4, 8, 12, 24, 36, 48 hours of ruminal incubation. Vetch seed processing, affected dry matter degradability so that steam flacked and roasted samples had the highest and lowest degradability percentage respectively (91. 06 vs 70. 49, P<0. 05). The crude protein degradability showed the same pattern as well (91. 64 vs 57. 52 percent for steam flaked and roasted vetch respectively, P<0. 05). Five different digestibility models were used to interpret degradability of dry matter and protein of raw and heat processed vetch seed. Ø rskov and McDonald's model with lag time was the best fitted model for dry matter degradability of raw, steam flaked and roasted vetch seed and Franc model was the best fitted model for microwaved vetch. Considering the crude protein degradability, the best fitted model were Dhanoa without delay phase for the raw and steam flaked vetch, Ø rskov and McDonald's with lag time for roasted vetch, and Dhanoa with lag time for microwaved vetch, respectively. Steam flaked and microwaved vetch had the greatest and lowest gas production during 48 hours incubation (184. 96 vs 141. 84 ml respectively, P<0. 05). Roasting increased metabolizable energy of vetch (4. 82 vs 5. 53 MJ/kg DM for raw and roasted vetch respectively, P<0. 05), however no changes was observed in ME content of vetch with microwave or steam flaking.

The use of molecular markers in recent years has been widely used to determine the genetic diversity between populations and animal species. Molecular genetics studies allow a comparison of genetic diversity within and across breeds and make a new insight to reconstruct the breed history and history of ancestral populations. The aim of this study was to investigate the genetic structure and genetic variation of indigenous and exotic sheep breeds using 50, 000 SNP markers. Genotype data of indigenous breeds (Afshari, Ghezel and Moghani) and exotic breeds (Dorper, Merinos and Romney) were obtained from the Ovin HapMap project. Multiple population stratification analysis such as, population structure using multivariate statistics and model-based approach were applied. The result of all methods obviously showed the correct population differentiation. In DAPC K=4 inferred best cluster results by BIC. Despite the use of different methods, all of these methods showed a distinct structure for indigenous and exotic populations and it can be concluded that Iranian sheep breeds has more genetic similarity rather than exotic breeds and Iranian sheep breeds grouped as one category and Romney, Merinos and Dorper breeds were separated as distant groups. However, when the indigenous breeds were studied alone, the breeds were genetically separated and population differentiation statistic (Fst) for Afshari, Moghani and Qezel was 0. 038, 0. 107, and 0. 298, respectively.

The aim of this study was bioinformatics and phylogenetic analysis for 5′ UTR region of neuropeptideY (NPY) gene and its association with body weight and egg production traits in Fars native chickens. For this porpuse 200 blood samples were collected from Fars Native chickens Breeding Center (Shamsabad station). The whole genome DNA was extracted using salting out protocol. The promotor region was amplified by PCR and SNP genotyping was performed by RFLP method. The frequencies of alleles A and B were estimated as 0. 46 and 0. 54, respectively. The population was deviated from H-W equilibrium. Statistical analysis indicated that there is no significant association between NPY genotypes and studied traits (egg number, age at first laying, egg weight at 84 weeks and body weight at 12 weeks). The results of phylogenetic analysis showed that the sequences of the NPY gene of Fars native chickens has the most simalirity with EU447658. 1 and EU447659. 1 sequence information. Interstingly, there is NPY gene of quail in phylogenetic analysis which can show the key role of NPY gene for regulating the physiological process.

The objectives were to evaluate effects of adding alfalfa hay (AH) as moisture absorbent to corn forage upon ensiling on silage fermentation, effluent production and performance of late lactating Holstein cows. Corn forage with the initial dry matter content of 22%, left untreated or ensiled with 5 and 10% AH, on a fresh weight basis, for 90 days. Silage DM linearly increased, while effluent production, pH, NDF and water-soluble carbohydrates concentration linearly decreased as AH inclusion rate increased (P<0. 05). An incomplete 2×3 Latin square experiment with nine late lactating Holstein cows consuming the above-mentioned silages showed similar nutrient intake and milk production and composition while a linear increase in organic matter digestibility with AH inclusion (P<0. 05). Total chwing and eating times were unaffected, however, chewing and ruminating time spent /kg DM linearly decreased as AH inclusion rate increased (P<0. 05). Ruminal pH and concentrations of VFA were similar across treatments. Results showed a strong effect of AH on reducing effluent from immature corn silage without having an adverse effect on silage fermentation and dairy cows’ performance. Using AH for controlling of effluent from corn silage is recommended.