Effect of timing of artificial insemination in relation to onset of standing estrus on pregnancy per AI in Nili-Ravi buffalo

Abstract

The aim of the present study was to determine the optimum time of artificial insemination after the beginning of standing estrus in buffalo. Nili-Ravi buffalo (n = 109) during breeding season were exposed to teaser bull at 12 hours interval to determine the standing heat (0 h). Buffalo were randomly allocated to different time groups and a single artificial insemination was performed either at 0 h (n = 30), 12 h (n = 27), 24 h (n = 28) or 36 h (n = 24). In a subset of buffalo (n = 38) ultrasonography was performed, twice daily from 0 h (onset of standing heat) to determine the time of ovulation. Pregnancy diagnosis was performed 35-40 days after AI. Results revealed that mean time of ovulation from onset of standing heat was 34.7 ± 0.96 h (range 30 to 42 h). Higher (P < 0.05) pregnancy per AI were achieved in buffalo when inseminated at 24 h (15/28; 53%) compared to 0 h (8/30; 26%) and 36 h (3/24; 13%). Pregnancy per AI, was in-between, in buffalo, inseminated at 12 h (10/27; 37%) and did not differ (P > 0.05) with those bred either at 24 h or 0 h. The odds ratio further confirmed that the occurrence of pregnancy per AI was two times higher in buffalo inseminated at 24 h as compared to those at 12 h. It is concluded that optimal pregnancy per AI can be achieved when buffalo are bred artificially 24 h after the onset of standing heat.

[Retracted] Study on Various Luteal Characteristics Using Doppler Ultrasonography for Early Pregnancy Diagnosis in Nili‐Ravi Buffaloes

“…Despite having a significant share in world's milk supply (97,417,135 tons/annum) [ 1 ], buffalo dairy production is affected by its reproductive attributes such as delayed puberty, seasonal breeding pattern, less pronounced estrus, variable time of ovulation, high embryonic mortality, and increased calving interval [ 2 , 3 ]. Milk yield per day is reduced significantly with the increase in calving interval resulting in economic losses [ 4 ].…”

Reproductive Performance of Water Buffalo Cows: A Review of Affecting Factors

“…Buffaloes with intense signs of estrus had a higher conception rate (81.16%) in comparison with those with intermediate (60.47%) and weak signs of estrus (44.11%) [190]. Artificial insemination early (0 and 12 hours) or late (36 hours) according to the beginning of the estrus reduced the pregnancy rate in comparison to artificial insemination that was carried out 24 after estrus beginning (26%, 37%, 13%, and 53%, respectively; P < 0.05) [191]. The phenomenon of silent estrus seems to be related to a lower follicular production of estradiol, which depends on the follicular diameter.…”

Effect of Prepartum Dietary Energy Level on Production and Reproduction in Nili Ravi Buffaloes

“…Estrus was detected after morning and evening milking with penile deviated teaser bull 40 to 100 days postpartum. Estrus was confirmed by measuring the largest follicle on the ovary and insemination with frozen semen was performed by a single technician 24 h after standing heat [30]. The presence of a large follicle at estrus and its absence after 24 h confirmed ovulation.…”