Pakistan Veterinary Journal (Feb 2009)
ESTRUS SYNCHRONIZATION WITH MEDROXYPROGESTERONE ACETATE IMPREGNATED SPONGES IN GOATS (CAPRA HIRCUS)
Abstract
An experiment was performed to synchronize estrus in goats by locally prepared progesterone-impregnated sponges and to determine the time of onset and duration of estrus alongwith subsequent fertility rate. The study was conducted from May to December, 2007 at NIAB (Nuclear Institute for Agriculture and Biology), Faisalabad. Polyurethane sponges were prepared with medroxyprogesterone acetate (MAP: 60 mg) and inserted intra-vaginally in a lot of 8 female postpartum goats (Beetal x Dwarf). Two goats were kept as control and were treated with sponges without MAP. Sponges were removed on 17th day of insertion and goats were examined for the signs of estrus at 6 h intervals. A buck was introduced in the herd for breeding, one day after removal of sponges. Estrus was further confirmed by determining serum estradiol levels using radioimmunoassay (RIA). All the experimental goats exhibited estrus within 21-100 h of removal of sponges, whereas one control animal also showed estrus. The average time from sponge withdrawal to the onset of estrus was 65.4 ± 24.0 h and duration of estrus was 29.8 ± 6.7 hours in experimental group. The control animal showed estrus after 22.0 h of sponge removal with estrus duration of 36 h. Estradiol concentrations in experimental lot were in the range of 2.2-15.0 pg/ml during estrus. Animals were observed for reversal towards estrus after 21 days. Only one experimental animal exhibited 2nd estrus. Pregnancy was confirmed by ultrasound after 60 days of sponge removal. The gestation period of 150.4 ± 3.4 days, a litter size of 1.3 ± 0.5 and a fertility rate of 87.5% were observed in the experimental lot. The control doe produced a male kid after 150.0 days of gestation. It is evident from this experiment that estrus can be synchronized in goats (Beetal x Dwarf) by locally prepared progesterone sponges with good fertility rate.
