Effect of prostaglandin alone and in combination with trace minerals on the follicular and luteal dynamics, estrus response and pregnancy in sub-estrus buffaloes (Bubalus bubalis).

Sub-estrus is a condition when buffaloes do not display behavioural estrus signs, despite being in estrus and causes a delay in conception and increases the service period. The present study describes the effect of synthetic prostaglandin (PGF2α) alone and in combination with trace minerals on the follicular and corpus luteum (CL) dynamics, serum estradiol (E2) and progesterone (P4) concentration correlating estrus response and pregnancy outcome in sub-estrus buffaloes during the breeding season. A total of 50 sub-estrus buffaloes, identified through ultrasonography (USG) examination, were randomly allocated into three groups, viz. T1 (Synthetic PGF2α, Inj. Cloprostenol 500 µg, i.m, n = 17), T2 (Synthetic PGF2α + Trace mineral supplementation, Inj. Stimvet 1 mL/100 kg body weight, i.m., n = 17) and control (untreated; n = 16). Following treatment, 100% of sub-estrus buffaloes were induced estrus in the T1 and T2 groups, while only 18.75% were induced in the control. The CL diameter and serum P4 concentration were significantly lower at post-treatment, whereas the pre-ovulatory follicle (POF) size and serum E2 concentration were significantly higher in the T1 and T2 groups as compared to the control (p < .05). The buffaloes of the T2 group had a greater proportion of moderate intensities estrus than those of T1. Moreover, the proportion of buffaloes conceived in the T1 and T2 were 41.2% and 52.95%, respectively. The larger POF diameter and higher serum E2 concentration were associated with intense intensity estrus and higher conception rate (66.7%) in sub-estrus buffaloes. Similarly, CL regression rate, POF size and serum E2 concentration were relatively higher in the buffaloes conceived as compared to those not conceived. It is concluded that synthetic PGF2α in combination with trace minerals induces moderate to intense intensities estrus in a greater proportion of sub-estrus buffaloes and increases the conception rate during the breeding season. Moreover, behavioural estrus attributes correlating follicle and luteal morphometry, serum E2 and P4 concentration could be used to optimise the breeding time for augmenting the conception rate in sub-estrus buffaloes.

Exploration of allelic variants in short tandem repeats (STRs) flanking milk production QTLs and their association with milk production traits in Indian water buffaloes.

Short tandem repeats (STRs) are co-dominant, highly polymorphic marker loci, distributed throughout the genome and useful for identification and mapping of QTLs associated with variation in traits of economic significance. Allelic variants were identified in STRs located in close vicinity of cattle QTLs for milk production,, viz. BMS713, BM6404, BM4513, BM121, BM6105, TGLA245, BL1100, BMS1948, BMS711, BM1443, BM1706, BM6438, BM143, BM415, ETH131, ETH 2, and BM1329 in 109 water buffaloes of Murrah breed. All loci except TGLA245 exhibited polymorphism of varying degree. The observed number of alleles, effective number of alleles, PIC value, observed heterozygosity, and expected heterozygosity across all STR loci averaged 4.12 ± 0.22, 3.20 ± 0.22, 0.60 ± 0.04, 0.34 ± 0.05, and 0.66 ± 0.03, respectively. Goodness of fit (chi-square) and likelihood ratio (G square) test demonstrated that the population exhibited a deviation from HWE for all the loci. FIS was positive and ranged from 0.22 to 1.00. Least square analysis of variance exhibited significant effects of BM4513, ETH131, BM713, and BM6105 on first lactational total lactation milk yield, 305-day milk yield, lactation length, and dry period respectively. None of the STRs could exhibit significant effect on peak yield.

Resumption of ovarian cyclicity and fertility response in bull-exposed postpartum buffaloes.

A study was undertaken to evaluate the effect of bull exposure on resumption of ovarian cyclicity and fertility response in postpartum buffaloes raised under standard farm conditions. A total of 24 Murrah buffaloes was randomly grouped to receive one of the following treatments: (1) exposure to a vasectomised bull from 40th to 90th day postpartum (bull-exposed, BE, n=11) and (2) isolated from bull (non-exposed, NE, n=13). Changes in the progesterone concentration were used to assess the resumption of ovarian cyclicity. Postpartum interval to resumption of ovarian cyclicity (47+/-2.58 days vs. 56+/-2.37 days, p<0.05) as well as behavioral estrus (57+/-3.61 days vs. 71+/-5.13 days, p<0.05) was shorter in bull-exposed animals than control animals. Similarly, animals in the BE group had significantly shorter interval to postpartum ovulation (48+/-2.69 days vs. 57+/-2.37 days, p<0.05). Reduced incidence of silent ovulation was observed in BE group compared to NE group (18.18% vs. 50%). More than half proportion of animals in BE group conceived by 60 days postpartum compared to a very low proportion of animals in NE group (54% vs. 15%, p<0.05). Furthermore, first service conception rate in BE animals was significantly greater than NE animals (100% vs. 37.50%, p<0.05). In conclusion, continuous bull exposure to buffaloes during later postpartum period accelerates resumption of ovarian cyclicity, reduces incidence of silent ovulation and enhances first service conception rate. These results indicate that introduction of bulls to buffalo herd could be a rational management strategy for reducing the postpartum anestrus by enhancing reproductive function in buffaloes.