Detection of Oestrus and Timing of Insemination for Better Conception | Animal Husbandry & Veterinary Science Optional for UPSC PDF Download

Detection of Oestrus

• Oestrus, the receptive period in females, crucially determines successful artificial breeding. Recognizing behavioural and physiological cues during this period is essential for effective oestrus detection.
• Common behavioural changes include frequent bawling, restlessness, micturition, licking behavior, mounting activities, and, in some cases, silent heat. 
• Additionally, a distinct discharge through the vulva, characterized by clear, viscous, and cohesive mucus, signifies oestrus. 
• Changes in the genital organs, such as vulva swelling, hyperemia of the vaginal mucous membrane, open cervix, turgid uterus, and the presence of a mature Graafian follicle in the ovary, further confirm oestrus.

Time of Insemination for Improved Conception

• Determining the optimal time for insemination is crucial for achieving a satisfactory conception rate. Breeding is generally avoided in the first 50-60 days post-calving to allow for complete uterine involution. 
• Conception rates are low at 30 days but increase by 60 days, reaching a peak at 80 days post-calving. Research indicates that sperm survival in the reproductive tract ranges from 24-48 hours for optimal fertility. 
• Notably, the fertile life of ova in cattle is reported to be 8-12 hours, emphasizing the significance of well-timed insemination within this narrow window.
• The recognition of these timeframes contributes to maximizing conception rates in artificial breeding programs.

• Van Demark and Moellar (1951) observed that in cows, sperm requires 2.5 minutes to reach the fallopian tube post-insemination. In buffaloes, Rao et al. (1960) reported a slightly longer duration, with sperm taking 4 minutes to reach the fallopian tube after insemination.

For optimal fertilization chances, it is crucial for spermatozoa to be strategically positioned, awaiting the ovum. This ensures a timely encounter between the two entities shortly after ovulation. Since both spermatozoa and the ovum undergo essential changes before fertilization, it is recommended to inseminate cows during the 'middle of estrus' or 6-18 hours before ovulation.