Department of Clinical Sciences, School of Veterinary Medicine, University of Shiraz, Shiraz, Iran
No published information are available on the reproductive indices of local Abadeh does reared in northern Fars province, southern Iran. This study was conducted to determine the duration of the breeding season, and the length and duration of the oestrous cycle. Twenty single parity 2-year-old does from Abadeh (weighing 19–26 kg) were purchased and transferred to the School of Veterinary Medicine of University of Shiraz. They had access to alfalfa hay, water ad libitum and natural light. Vasectomised teaser buck was turned with the flock and observation was made every 12 hrs during the day for standing heat detection, from late-August (2003) to late-August (2004). To determine the onset of reproductive activity as well as occurrence of silent oestrus, blood samples were collected from jugular vein every 10 days. Following the onset of breeding season and observation of standing heat, 10 does were randomly selected in their 2nd oestrous cycle for twice weekly blood sampling. Serum progesterone concentration was determined using a commercial radioimmunoassay kit. It was found that silent oestrus occurs mostly in early breeding season. The first standing heat was observed in mid-September which was considered as the onset of breeding season. Occurrence of standing oestrus increased through October, November and December. The peak of standing oestrus was recorded during late-October to early, mid-November. The mean ± SD duration of the oestrous cycle was 19.7 ± 1.1 days and the mean ± SD length of oestrus was 23.8 ± 12.3 hrs. The mean (±SD) concentrations of serum progesterone in days 0 (day of standing heat) to 4, varied between 0.1 and 0.8 ng/ml. Concentrations of progesterone during the luteal phase varied between 2.7 and 3.9 ng/ml. The results of progesterone assay during oestrous cycle indicate that the follicular and luteal phases last about 4–5 days and 14 days, respectively. In conclusion, oestrus activity in local Abadeh does is highly seasonal with a peak of activity being observed during the late-October to the end of November.