Seasonal variation of fibre follicle activity and wool growth in fat-tailed Sanjabi sheep in west Iran.

This experiment was conducted to investigate the seasonal pattern of hair follicle activity, wool growth and fibre diameter (FD) in Sanjabi sheep in west Iran, Kermanshah (34° 18' N and 47° 3' E, elevation 1420 m). Ten male and 10 female Sanjabi sheep with an initial live weight of 32.1 ± 1.3 and 32.7 ± 1.5 (means ± SD), respectively, were used in a 365-day study. A diet was offered with an estimated concentration of 2.18 Mcal metabolizable energy and 130.0 g/kg DM crude protein. Body weight, average daily gain (ADG) and dry matter intake (DMI) were recorded weekly. The percentages of active primary and secondary wool follicles (PAP and PAS), follicle density and the ratio of secondary to primary follicles (S/P) were determined from skin biopsies, taken from the right mid-side of the sheep at monthly intervals. Raw and clean fibre growth rates and FD were measured from left mid-side patches (10 × 10 cm) harvested at the end of every month. There was a gradual increase in live weight throughout the experiment, while ADG and DMI changed in concert with day length. The greatest values for PAP and PAS were observed in summer, whereas lowest were obtained in winter (p < 0.001). Clean wool growth rate and FD were greatest (p < 0.001) in summer and lowest (p < 0.001) in winter. It is concluded that a seasonal cycle of feed intake, body growth, fibre follicle activity, wool growth and FD occur in fat-tailed Sanjabi sheep.

Endocrine markers for identifying prolificacy potential and predicting fetal number in goats.

Identifying prolificacy potential and determination of fetal number during pregnancy for proper care and management of the pregnant goats bearing multiple fetuses and achieving the benefits out of multiple births are essential for sustainable goat farming. Our objectives were (1) to examine prolificacy potential in goats by using pituitary response to gonadotrophin releasing hormone (GnRH) challenge test, (2) to investigate hormonal profiles for the prediction of fetal number in pregnant goats and (3) to find out the most reliable timing of blood sampling for discriminating prolificacy trait and differentiating the goats bearing single, twin and triplet fetuses. In first experiment (GnRH challenge test), plasma FSH concentrations were significantly higher (P<0.01) among the goats belonging to triplet vs. twin vs. single kidding size groups after GnRH administration. Multivariate stepwise discriminant function analysis recognized that one blood sampling at 220min after GnRH administration can be used to distinguish prolificacy potential in goats. In second experiment, plasma progesterone levels were significantly higher (P<0.01) in goats bearing triplet vs. twin vs. single fetus between day 84 and 21 prior to parturition. Plasma estrone sulphate concentrations were found to be higher (P<0.05) in does bearing multiple fetuses than the does bearing single fetus between day 126 and 28 prior to parturition. A single blood sampling at day 63 prior to parturition was the most probable suitable time for discriminating kidding size by using plasma progesterone as marker.

Steroid hormone profile of Markhoz does (Iranian Angora) throughout estrous cycle and gestation period.

The present study aims were to determine the profiles of changes in progesterone (P4) and 17-ß-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.