فصلنامه تحقیقات تولیدات دامی
سال چهارم شماره 2 (تابستان 1394)

In this study, nine Taleshi rams (approximately 3 years old and average BW was 55.6±1.57 kg) were selected randomly and allocated into three groups to investigate the effect of melatonin (regulin) on sperm during breeding and non-breeding seasons. The first group (control) did not receive any regulin, the rams of second group received one regulin and finally, the third group received two regulins subcutaneously at the same time. Scrotal circumference (SC), semen volume, sperm concentration, sperm motility and sperm viability of all rams were measured on day zero (regulin implantation day). Scrotal circumference was measured 45 days after regulin implantation and semen volume, sperm concentration, sperm motility and viability were measured 46, 50, 54 and 58 days after regulin implantation. The results indicated that the use of regulin had not any significant effect on the SC and sperm quantity and quality parameters during breeding season (P 0.05). The SC and motility were increased by using two regulins during non-breeding season and this improved sperm viability in comparison to control group (P<0.05). Whereas, the use of regulin had not significant effect on semen volume and sperm concentration (P>0.05). It is concluded that improvement in the ram semen quality was expected with the use of two regulins during non-breeding season.

The current study was aimed to investigate the effect of Primalac probiotic, Fermacto prebiotic and their composition on growth performance, carcass quality and decreased requirements of protein and energy in broilers diets. A number of 720 one day male and female Cobb 500 chicks were allocated to 6 treatments with 4 replications and 30 chicks for each replication, under a completed randomized design. Treatments were consisted of A: control (without the additives); B: control+ recommended level of Primalac in each growth stage; C: control+ recommended level of Fermacto in each growth stage; D: control+ 50% of recommended level of Primalac+ 50 % of recommended level of Fermacto in each growth stage; E: control+0.5% lower protein+50 kcal/kg lower ME+ 50% of recommended level of Primalac and Fermacto in each growth stage; and F: control+1% lower protein+100 kcal/kg lower ME+ 50% of recommended level of Primalac and Fermacto in each growth stage. No significant difference did exist (P>0.05) among various treatment for body weight gain, feed intake, feed conversion ratio, carcass relative weight, and percentage of carcass, leg, breast, heart, small intestine, abdominal fat, spleen and bursa of fabricius. Treatments E and F, in spite of lower level of dietary protein and energy, had similar performance with other treatments. Therefore the influence of probiotics and prebiotics appears when the diet nutrient content or its availability is restricted.

Two independent experiments were carried out to investigate the effects of natural aluminosilicates and glauconite in sheep nutrition. At 1st experiment, dry matter disappearance of these minerals by two particle sizes (0.85-1 mm and <0.5 mm), was determined. For this, 3 fistulated Dalagh rams in a completely randomized design with factorial arrangement 2×4 by nylon bag technique were used. 2nd experiment conducted to investigate dietary effect of zeolite and perlite on feed intake, nutrients digestibility, fecal moisture and blood parameters. 2nd experiment carried out in a change-over design by 4 treatments, 4 periods and 4 non pregnant Dalagh ewes. Each experimental period was 15 days, including 10 days as adaptation and 5 days for total feces collection. Dietary treatments were: 1) control 2) control diet + two percent zeolite, 3) control diet + two percent perlite and 4) control diet + one percent zeolite + one percent perlite. Analysis of variance and separation of means by Duncan's multiple range tests were conducted by SAS software. 1st experiment showed that between two particle sizes of bentonite, there was no significant difference in dry matter disappearance (P>0.05), While, in other minerals these amount having certain trend for larger size, in any time, that was lesser than smaller size significantly (P<0.05) whereas maximum difference shown in zeolite supplemented treatment that in 48 h. were 6.71 and 52.03% in coarse and fine particle size respectively. The 2nd experiment indicated that 2% zeolite supplemented treatment had significantly higher apparent digestibility of CP, Ca and P in comparison to other groups (P<0.05). Supplementation of ewe diet by two percent zeolite and perlite can be lead to better performance.

The aims of this experiment were to determine the nutritive value and investigate the possibility of ensiling pumpkin by-product (PBP) using wheat straw, wheat bran and urea. The data were analyzed in acompletely randomized design with factorial arrangement 3×4. Chemical composition of PBP before ensiling was determined. Before silage preparation, wheat straw, wheat bran and urea were mixed (90, 8 and 2 percentages, respectively). After that PBP was ensiled with mixed ingredients in different proportions including the ratios of 70, 75, 80and 85 percent PBP and 30, 25, 20 and 15 percent of mixed ingredients respectively. Silages were opened at 30 and 60 days after ensiling. Nutritive value of silages was determined using gas production test at the 0, 30 and 60 days of ensiling. Water soluble carbohydrate, dry matter, ash, crude protein and ether extract of PBP were 6.8, 9.68, 11.46, 21.69 and 5.87 percent respectively. As the proportion of PBP in the silages increased, pH and NH3 decreased but buffering capacity and residual water soluble carbohydrate content increased. Data of in vitro gas production test indicated that potential gas production (b) and lag time (L) were not affected by the levels of PBP, however fractional rate of gas production (c) was influenced (P<0.05). Overall results showed that ensiling PBP with wheat straw, wheat bran and urea for a period of 30 days is a suitable method for preservation of nutritive value of PBP.

Effects of different levels of energy and protein of diets on fattening and growth performance of kids were investigated by using 54 weaned native male kids. Experimental kids were randomly assigned in a randomized complete design with a factorial arrangement of 3×3. They received two main elements source of energy and protein in ration with three levels of each in diets of 1 to 9 for 90 days. Levels of metabolizable energy in ration was E 2.4, E 2.8 and E 2 Mcal/kg and levels of theirs crud protein was P.14, P.16.8 and P 12 percent respectively. Ratios of energy to protein in consumed experimental diets were equivalent 1.2, 1 and 0.8 of NRC. Daily feed intake, feed conversion ratio and daily gain of fattening kids were determined. The result showed that highest and lowest of final fatten weight and daily gains of kids were observed in diet of E 2.8: P 16.8 and E 2: P: 14 ratio with value of 35.7 and 32.5 kg respectively (P<0.05). The least and highest of daily dry mater consumed was observed in diets of E 2.8: P 16.8 and E 2: P12 ratio and amounts of 788 and 970 gr respectively (P 0.05). The lowest (best) and worst of feed conversion ratio were observed in diets of E 2.8: P 16.8 and E 2: P: 12 with amounts 6.9 and 10.5 respectively (P<0.05). It can conclude that energy and protein levels suggested by NRC were appropriate for these animals.

Using a deterministic model,the changes in generation interval forpathway of dam of dams as a result of sex sorted semenutilization in heifersunder various reproduction conditions was investigated. Three sex sorted semen using strategies were considered.They included continuous usage of sex sorted semen over all inseminations (CS); the use of sex sorted semen atonly first and the second inseminations (S2), and the use of sexed sorted semen atonly the first insemination (S1). Various reproduction situations were described by conception probability associated to using sex sorted semen and conventional one. The results indicated that generation interval by various strategies and reproduction situations varied from 4.0506 to 4.2063 years. Utilization of sex sorted semen by S1 strategy led to shorter generation interval in all situations of reproduction. The shortest range of variation in generation interval under various conditions was due to using S1 strategy (0.08 years) and the highest one was attributed to CS strategy (0.15 years). In general, generation interval for the pathway of dam of dams resulting from using sex sorted semen was longer than that of conventional semen, but was negligible (up to 0.1 years). In the case of necessity for sex sorted semen, it would be recommendable to apply S1 strategy.

The genetic diversity of the world’s livestock populations is decreasing, both within and across breeds. The conservation of livestock genetic variability is thus important, especially when considering possible future changes in production environments. Current research focuses on GIS analysis of the sheep diversity based on fecundity and DNAmarkers of four sheep breeds over Iran. A totalof 97 mature ewes (Afshari=19; Baluchi=18; Makui=30 and Mehraban=30) collected with known single or twin lambings from different locations of Iran to assess genetic diversity of fecundity using morphology, DNA information analysis and DIVA-geographic information system (GIS). Polymorphism of two GDF9 and BMP15 candidate geneswas investigated using PCR RFLP. Litter size was significantly influenced by genotype of each gene, and heterozygous genotypes for both loci showed higher litter size than the homozygous genotypes (P<0.01). According to the obtainedresults, the regions that are richest in diversity located in North West of Iran. DIVA-GIS showed the highest diversity index for fecundity between Iranian indigenous sheep. The highest diversity index for fecundity was observed in the sheep breed from North West parts of Iran.