The objective of this experiment was to study wheather the administration of GnRH plus PGF2 alpha synchronizes the estrus in anestrus crossbred cows exposed to bull urine (BU) during the winter season (Nov to Feb). The results indicated that a greater proportion of BU-exposed cows (n=20) showed estrus as compared to control (n=8) (90 vs 37.5 % P0.05). The mean plasma progesterone concentration remained below 1ng/ml in all animals of each group during the treatment period. The overall conception rate was double in BU-exposed cows (66.7 vs 33.3 % P0.05). From this experiment it can be concluded that oro-nasal application of BU synchronizes the estrus in a greater proportion of anestrus cows treated with GnRH plus PGF2 alpha during winter season.

The objective of this study was to evaluate cost-effective intervention for enhanced fertility in buffaloes, which could otherwise remain un-bred for variable long time. A total of 165 postpartum anestrus buffaloes were examined gynaeco-clinically at farmer's door. The animals identified with corpus luteum in either of the ovary, were treated with 500 £gg of Cloprostenol, single injection or double injection at 11 days interval (Gr. I). The remaining animals with smooth and inactive ovaries were randomly divided in three different groups. The group II animals were injected 100-150 mg progesterone for successive 5 days and single injection of 500 I.U. of PMSG on seventh day. The animals of group III were administered with 20 £gg of GnRH analogue and 7 days later, with 500 _Ýg of Cloprostenol. A second injection of 10 £gg GnRH analogue was given after 48 hrs of Cloprostenol injection. Group IV animals received 50 gm mineral mixture daily for 30 days along with 30 Nutrisacc boli (1 bolus b.i.d. for 15 days). The proportion of animals that exhibited estrus were 89.13, 86.84, 82.35 and 59.57% and the mean treatment-estrus intervals were 3.97¡Ó0.46, 4.38¡Ó0.49, 3.08¡Ó0.23 and 21.78¡Ó2.56 days in group I, II, III and IV, respectively. The animals detected in estrus were bred by natural service using fertile bulls and diagnosed for pregnancy per rectum 50 days post service. The first service conception rate was 46.34, 33.33, 53.57 and 28.57 % in-group I, II, III and IV, respectively, while the overall conception rate was significantly higher (78.57%) in GnRH-treated animals. The cost of treatment in different groups was Rs. 160 or 320, 220, 525 and 150, respectively. The results indicate that better fertility in postpartum anestrus buffaloes can be obtained by GnRH therapy though; the cost of intervention seems to be higher than other treatments.