Importance of Oestrus (Heat) Detection in Dairy Animals


India is the major player in world dairy industry contributing 17% of total world milk production. As per an assessment made by the Planning Commission of India, the domestic demand for milk by 2021-22 is expected to be 172.20 million tonnes. However, so far the country has not been able to keep pace with the domestic demand for milk. Reproductive disorders and associated infertility (transient loss of fertility) among cattle and buffaloes pose serious economic loss to farmers in terms of low returns and veterinary expenses. After mastitis, the reason for largest loss is improper oestrus detection in dairy animals. In Indian condition, about Rs. 5000-7000 loss (in term of cost of feed, labour, milking, medicine and veterinary expanses, parallel keeping breeding bull) if one heat is missed without insemination and conception. If heat can be identified at proper time, then it is easy to perform artificial insemination (AI) at proper time and ultimately improved conception rate.


Fertility over the past few decades is of serious concern in the dairy industry. Fertility of a dairy herd is determined by composite factors, which in turn depends upon effective management strategies. The reproductive potential of the animals need to be exploited to its maximum to achieve optimum production in a herd. The single most important factor that limits the establishment of pregnancy and survival of the embryo in dairy cattle and buffaloes and thereby reproductive efficiency of a herd is proper estrus detection. More commonly, animals are diagnosed to be in estrus based on the appearance of mucus discharge, mounting or standing to be mounted and other physical activities. However, there exist a lot of variations regarding the actual time of onset of estrus.


The routine AI program involves AM/PM schedule for insemination i.e. animals found in estrus in the morning are inseminated in the same day evening and those in estrus in the evening are inseminated next morning. This protocol is recommended based on the fact that the interval between onset of estrus and ovulation rages from 25 to 38 h. But there exists a lot of difference between the “animal found in estrus” and “on set of estrus” and they are interchangeably interpreted in several occasions and that compromises the conception rate. Proper estrus detection is the biggest bottleneck in achieving high conception rate with artificial insemination in dairy animals. It has been reported that only 11.05 % of cattle and 20.75 % of buffaloes are inseminated at improper time (Kumaresan et al., 2001), which clearly indicated that the cows were wrongly detected as in estrus and insemination of these cow incurs heavy loss in term of wasteful expenditure of quality male germplasm, production loss and increased risk of introducing genital infection in female. Faulty estrus detection not only entails wasteful expenditure of quality male germplasm and losses associated with production in female animals but also increase the chance of introducing genital infections in the female that are inseminated wrong time.


Table 1. Duration of oestrus in different breeds of bovine

Various management factors contribute to failures to diagnose estrus. Besides, that concentration of the estrogenic substance present in plants or fodders varies according to different seasons of the year, short duration estrus behavior in lactating cows, poor estrous behavior when housed on concrete flooring, as well as duration and intensity of light to which the animals are exposed also influence the onset of estrous cycle. Thus, the estrus detection efficiency and accuracy are the most important parameters for improving both the individual animal as well as overall herd fertility as pregnancy is achieved for each cow within a determined period (Boyd, 1984).

Fig: 1. Visual Observation (Standing to be mounting)

PC: Author


Reproduction management is an economic determinant in the success of any dairy enterprise. Fertility in dairy animal is making the animal pregnant in right time. This to happen we have to concentrate on two traits i.e., to make cow cycling and showing oestrus and detecting it in right time and making the cow pregnant following an insemination. Among many components of reproduction management, oestrus detection is the crucial one, as it contributes towards the ultimate pregnancy rate and survival of the embryo (Layek et al., 2011, 2013). Inadequate heat detection has been identified as a major limit to herd reproductive performance over many years.


Conclusion

Each missed heat represents the loss of a complete oestrus cycle of approximately 21 days that in a seasonally calving herd represents 21 days of lost potential production, so each missed heat has a significant financial loss. In this regard, attaining higher oestrus detection efficiency and accuracy is an important key to improve individual animal along with overall herd fertility. Fertility traits can be expressed as day’s open, calving interval and number of AI services needed before pregnancy.


Authors

1, 2. Ph.D Scholar, Livestock Production Management Section, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, U.P., India.

3. College of Veterinary & Animal Sciences,Udgir, Latur, Maharashtra

Citations:

Boyd, H. W. 1984. Aids to estrous detection- A review.In Dairy cow fertility.Proc. Joint Brit. Vet. Assoc. and Brit. Soc. Anim. Prod. Conf., Bristol, U.K .pp 61–67.

Dash, P.C. 1980. Reproductive behaviour of dairy cows (Bosindicus, Bostaurus and Bostaurus X Bosindicus). Ph.D. Thesis. (NDRI) Punjab University, Chandigarh.

Esslemont, R. J., and Bryant, M. J., 1976.Oestrous behaviour in a herd of dairy cows.Vet. Rec. 99, 472–475.

Kumaresan, A., Ansari M. R. and Sanwal, P. C. (2001).Assessment of the accuracy of oestrus detection by progesterone assay in cattle and buffaloes.Indian J. Anim. Sci.,71(8): 34–36.

Layek, S.S. Mohanty, T.K., Kumaresan, A., Behera, K. and Chand, S. 2011a. Behavioural signs of estrus and their relationship to time of ovulation in Zebu (Sahiwal) cattle. Anim. Reprod. Sci., 129(3): 140-145.

Layek, S.S. Mohanty, T.K., Kumaresan, A., Behera, K. and Chand, S. 2013. Cervical mucus characteristics and periestrual hormone concentration in relation to ovulation time in Zebu (Sahiwal) cattle. Livestock Science,152(2): 273-281.

Roelofs, J. B., van Eerdenburg, F. J. C. M., Soede N. M and Kemp. B. 2005. Pedometer readings for estrous detection and as predictor for time of ovulation in dairy cattle.Theriogenology, 64:1690-1703.

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