Iranian Journal of Veterinary Science and Technology
Document Type : Research Articles
Authors
1
Animal Science Department, Faculty of Agricultural Sciences, University
of Guilan
2
Unversity of Guilan
3
Animal Science Research Department, Guilan Agricultural and Natural
Resources Research and Education Center, AREEO, Rasht, Iran
Abstract
The
present study was conducted to assess the seasonal breeding of Caspian
horses in 10 mares during a year. Mares were divided into two age
groups: 3-6 years (young) and 7-19 years (old). Blood samples (n=530)
were collected weekly. The ovarian activity was evaluated by the
concentration of progesterone. Mares with serum progesterone
concentrations consistently higher and lower than 1 ng/ml were
considered cyclic and non-cyclic, respectively. Results showed an
interaction between time and age on the concentration of serum
progesterone, ovarian activity, body weight, and body condition score
(BCS) (p < 0.05). In March, the concentration of serum
progesterone was higher in young mares (7.84 ± 1.14) than in old mares
(1.26 ± 1.14, p < 0.05). The serum progesterone was higher in old
mares than in young mares during July-November (p < 0.05). Ovarian activity was higher in young mares than in old mares during February-April (p < 0.05). Ovarian activity was higher in old mares than in young mares during July-November (p < 0.05). The length of the breeding season was higher in old mares than in young mares (p < 0.05). BCS was higher in young mares (4.4 ± 0.22) than in old mares (3.2 ± 0.22) in February (p < 0.05). Body weight was lowest in the young mares during September-January (p
< 0.05). There was a significant correlation between ovarian
activity and BCS of Caspian mares. Finally, seasonal breeding was
shorter and earlier in young Caspian mares compared to old mares