Comparison of the effect of Gonadotropin-Releasing Hormone and Human Chorionic Go3nadotropin on Reproductive Performance of Romanov Ewes During the Natural Breeding Season.

Low pregnancy rate is an important issue in small ruminants. Superovulation protocols would serve as the possible techniques to increase the pregnancy rate in small ruminants due to the use of synthetic hormones. The present study aimed to assess the effect of gonadotropin-releasing hormone (GnRH) and Human chorionic gonadotropin (hCG) after artificial insemination (AI) on the pregnancy rate of Romanov ewes breed. To this end, estrus was synchronized in 140 ewes using a controlled internal drug-releasing (CIDR) device. Following CIDR removal, all ewes received 400 IU Pregnant Mare's Serum Gonadotropin (PMSG). The ewes were assigned to three groups (control, n=20; experimental groups, each of them was divided into three subgroups, n=20). The first group in each experiment was assumed as control. The second and third groups received three levels of GnRH, (400, 500, and 600 µg, n=20) and hCG (200, 300, and 400 IU) administered by the intramuscular (IM) route. As soon as the signs of estrus were observed, the ewes were isolated from the others and artificially inseminated with fresh sperm using the transcervical method. The results indicated that there were no significant differences between experimental groups in ovulation and pregnancy rates on days 33 and 90 post-AI (P>0.05). The highest twin birth rate (20%) was recorded in the hCG group (300 IU), as compared to GnRH and control groups (P<0.05). The effect of GnRH and hCG on the plasma concentration of progesterone was significant (P<0.01). The groups significantly differed in fecundity rate (Single birth, twin birth, and triple birth) (P<0.05), all of these parameters were significantly higher in the hCG 300 IU group. It can be concluded that the injection of 300 IU of hCG hormone after insemination improves pregnancy rate in ewes.

Effects of Flaxseed-rich Diet on Reproductive Performance in Estrous-synchronized Baluchi Ewes.

The purpose of this study was to compare the effects of using different levels of flaxseed in diets on the reproductive performance of estrous-synchronized Baluchi ewes (para 3). Diets contained either basal diet (control) or different levels of extruded flaxseed (2%, 5%, 7%, 10%, and 12%) and were fed from lambing to 60 days after lambing. The ewe estrus cycles were synchronized using controlled internal drug release (CIDR) for 14 days starting from day 16 of fat supplementation. The rams were introduced 24 h after CIDR removal. The ewes fed control diets had the highest mean dry matter intake (1,800&plusmn;35 g) which was declined with the increase of flaxseed levels. The experimental diets exerted no effects of urea concentration in blood plasma. However, plasma glucose concentration was lower (p &lt;0.05) in the ewes fed the control diet and 2% flaxseed, compared to those in other groups. Nonetheless, there was no difference among the ewes fed 5%, 7%, 10%, and 12% flaxseed in terms of plasma glucose concentrations (p &lt;0.05). The ewes fed 2% flaxseed had the highest level of plasma triglyceride concentration among other groups. In addition, the control group had the lowest level of plasma total cholesterol and low-density lipoproteins concentration in comparison to other groups (p &lt;0.05). However, plasma nonesterified fatty acids and &beta;-hydroxybutyrate concentrations were similar among the groups (P&gt;0.05). The mean interval between CIDR removal and the exhibition of estrus ranged from 30 to 40 h with the shortest interval being recorded in the ewes fed 12% flaxseed (p &lt;0.05). The control group had the lowest number of follicles on estrus day among other groups (p &lt;0.05). Furthermore, the ewes fed 10% and 12% flaxseed had the highest ovulation, pregnancy, and lambing rates, compared to other groups (p &lt;0.05). In conclusion, the findings revealed that feeding the ewes with 10% and 12% flaxseed resulted in the improvement of reproductive performance.

Characterization and Pattern of Culling in Goats.

In order to describe the proportion and pattern of culling in commercial goatherds, this survey was carried out in an industrialized goatherd in Torbat-e-Jam, Iran, over a period of 18 years from 1996 to 2013. In total, the data of 3945 goats were used in this study. Finally, out of all samples, 499 (12%) goats were culled. The involuntary culling was performed mainly due to shortage disorders (3.8%), viral disorders (3.3%), microbial diseases (2.8%), and other disorders (2.1%). Sheep pox was the most important reason (64%) for culling due to viral disorders. Tick paralysis was the most common parasitic disease that contributed to culling and responsible for 88% of parasitic disorders. On the other hand, enterotoxemia accounted for 55% of microbial disorders is considered the most common cause of culling. The high proportion of culling due to shortage disorders, especially nutritional deficiencies should be considered the most important cause of culling. It requires precautionary measures and planning in order to reduce the aforementioned rate.