Reproductive characteristics of Rayini male goats of Kerman province in Iran

An artificial vagina was used to collect semen from 14 native Iranian Rayini goats, at 15-day intervals starting on 1 July and ending on 30 December 2000. Testicular size, semen volume, sperm concentration, percent live sperm, percent normal sperm, and total number of live-normal sperm were significantly higher during the summer months. The average semen volume, percent live sperm and percent abnormal sperm during the sampling period varied between 1 and 1.4 mL, 60 and 78%, and 7 and 13%, respectively. The total number of live and normal sperm in the ejaculate during the sampling period varied from 1000 to 2500 million. Testicular size, semen volume and the total number of live and normal sperm were significantly greater in bucks weighing 55–60 kg as compared with 50–54 kg. Seminal fluid pH values were significantly lower from July to October (pH <6) than the values from November to December (pH >6.1). Lowest level of lactate dehydrogenase in the seminal fluid was recorded in early September (2.2 U/mL) and the highest level in November (2.5 U/mL). Seminal fluid K ion level increased gradually from July (52 mg/dL) to the November (97 mg/dL). Variation of seminal fluid Na ion concentration (71–74 mg/dL) was not significant during the sampling period. The correlation coefficients of total number of live-normal sperm with seminal fluid K level (r = −0.65) and LDH (r = −0.36) were negative (P < 0.01). The data indicated that the semen quality and quantity of Rayini bucks were higher during summer and early autumn.