No abstract

No abstract

2018) Influences of dietary selenium, zinc and their combination on semen characteristics and testosterone concentration in mature rams during breeding seasonABSTRACT This study was conducted to determine the effect of dietary supplementation of organic zinc (Availa®Zn100) and selenium (Availa®Se1000) on semen characteristics, testes measures and serum testosterone concentration. Twenty Sanjabi rams (50.01 ± 5.6 kg) were randomly divided into four equal groups, given the basal diet as control (C) or supplemented with 0.3 mg/kg Se (SE) or 40 mg/kg Zn (ZN) or 40 mg/kg Zn plus 0.3 mg/kg Se (ZS) for 120 days experiment (from July to November). The semen samples and blood samples were collected every 3 weeks and scrotal circumference was measured every 15 days. The results indicated that scrotal circumference and testosterone concentrations did not differ due to treatment (P > .05). In contrast, semen characteristics were affected by ZS supplementation. The sperm density and total sperm number increased (P < .05) in ZS group. In addition, the progressive sperm motility was higher in ZS (P < .05) than those of SE and C groups. It is concluded that ZS treatment can improve semen characteristics, which may result in overall improvement in reproductive performance of treated Sanjabi rams during the breeding season. ARTICLE HISTORY

No abstract

No abstract

The present study aims were to determine the profiles of changes in progesterone (P4) and 17-β-estradiol (E2) in the peripheral blood of Markhoz goat (Iranian Angora) during estrous cycle, gestation, and parturition throughout natural breeding season. Gestation length averaged 145.3 ± 0.8 days, and the litter size was 1.1 ± 0.1. Birth weight ranged 2.4-2.8 and 1.5-2.5 kg in male and female kids, respectively. The mean estrous cycle lengths were 20.3 ± 0.4 and 20.9 ± 0.4 days for PGF(2α)-induced and natural cycles, respectively. Blood sampling was carried out daily during estrous cycle and weekly during gestation till parturition. E2 attained higher level (24.7 ± 2.15 pg mL(-1)) at estrus phase and dropped down to the lower level (18.80 ± 1.16 pg mL(-1)) within 3 to 4 days post-estrus. Concomitantly, P4 started to increase from the mean basal value of 0.5 ± 0.03 ng mL(-1) on day 0 to 6.88 ± 0.95 ng mL(-1) on day 6 of estrous cycle and reached the peak value of 12.8 ± 0.61 ng mL(-1) on day 12. From day 15, a decline was observed in P4 values till the end of the cycle. P4 remained at lower concentrations for 20-50 days of gestation, then increased and reached to its maximum level (13.51 ± 0.279 ng mL(-1)) in week 15 and returned again to its basal values within 1-2 weeks before parturition. The results will be discussed in terms of the usage of steroid hormone profile in several assisted reproductive technologies.

No abstract

Ten Scottish male castrated cashmere-yielding (C) and 10 Angora (A) goats with initial live weights of 38·2 (C) and 32·1 (A) kg respectively were used in a 112-day study in the time period August to December. The goats were blocked within genotypes according to live weight and randomly assigned to one of two treatments: either no supplementation (O) or dietary supplementation (S) with 2·5 g/kg dry matter (DM) intake of rumen-protected intestinally available methionine (Smartamine™ M, Rhone Poulenc, Animal Nutrition, Antony 92164, France) in a 2 × 2 factorial arrangement.The goats were offered a basal diet in the proportion of 0·6, grass hay and 0·4 concentrate according to their live weight. Diet metabolizable energy (ME) and crude protein (CP) concentration per kg DM were estimated as 9·9 MJ (ME) and 107 g (CP) and DM intake was restricted to 28 g/kg live weight daily. Apparent digestibility and nitrogen (N) balance studies were conducted from days 24 to 40 and 51 to 64. Measurements were made within three time periods of days 0 to 40, 41 to 75 and 76 to 112.Angora goats excreted less urinary N than cashmere-yielding goats and had lower values for plasma urea and glucose and greater overall retention ofN, associated with a two- to three-fold greater total fibre yield. Cashmere as a proportion of total fibre by weight, (guard hair plus cashmere) varied from 0·27 to 0·43.The main effects due to methionine supplementation were improvements in live-weight gain and food conversion ratio. Reductions in urinary N excretion and increases in N retention were recorded, which were generally greater for Angora than for cashmere-yielding goats, and were again associated with the larger responses in fibre production. Clear evidence was also obtained for methionine-induced increases in the weight of raw cashmere, although not guard hair up to day 58. This response was obtained in the absence of significant effects on cashmere diameter, although methionine supplementation consistently increased the average diameter of mohair fibres.