PG Thesis

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Subject: search.filters.subject.crossbred cows

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    Post-partum reproductive performances of crossbred cows
    (Department of Animal Reproduction, College of Veterinary and Animal Sciences, Mannuthy, 1981) Bhaskaran, K V; Neelakanta Iyer, C P
    The object of the present investigation was to study the various aspects of the post-partum reproductive performances of crossbred cows and to assess the reproductive efficiency by breeding cows before and after 60 days post-partum. Fifty two freshly calved and randomly selected crossbred cows, belonging to the University Livestock Farm, Mannuthy formed the materials for the study of genital involution, cyclic ovarian acivity and post-partum oestrus. These animals were grouped into normal and abnormal calvers and data recorded and analysed. Twenty four crossbred cows, selected at random, were weighed at fortnightly intervals, commencing from the day of calving till 90 days post-partum to study the pattern of gain or loss in weight and its influence on the post-partum heat and conception. To study the effect of early breeding on the future reproductive efficiency 38 crossbred cows in oestrum were grouped into three. Group I was inseminated between 30 and 45 days, group II between 46 and 60 days and group III after 60 days post-partum and fertility assessed. Data collected were subjected to statistical analysis. The observations made and inferences drawn are summarized below: Abnormal calving significantly delayed the involution of uterus, cessation of uterine lochia, involution of vulva, regression of pregnancy corpus luteum and onset of first observed oestrus, The rate of uterine and vulval involution were significantly higher in primpara than pluripara. In contrast, primparous cows took a significantly longer interval for the onset of first observed heat. However, breed of the cow, milk yield and sex and weight of calf did not influence any of the parameters studied. Animals gained in body weight after calving exhibited early oestrum and better fertility. Further, breeding of cows, between 30 and 60 days after calving yielded high fertility without adversely affecting milk yield, thus reducing the service period and calving interval.
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    Heat stress alleviating measures for crossbred cows
    (Department of Livestock Production Management, College of Veterinary and Animal Sciences, Mannuthy, 1999) Thirumurugan, P; Saseendran, P C
    An experiment was conducted to find the effect of sprinkling water on crossbred cows during summer season of Kerala.Twelve early lactating crossbred cows were selected and put into four groups of three each and were randomly allotted to four treatments as open house with sprinkler (T1), open house without sprinkler (T2), tie-barn with sprinkler (T3) and tie-barn without sprinkler (T4). The mean maximum temperature recorded in the T1, T2, T3 and T4 locations were 32.03, 32.17, 33.27 and 33.40oC respectively and these were lower than the maximum temperature recorded outside the animal houses (35.45oC). Both within the tie-barn and within the open house, the mean maximum and minimum temperatures and mean relative humidity morning and afternoon did not differ significantly due to sprinkling of water.But the differences between the tie-barn and open house were highly significant (P<0.01) and higher in the tie-barn for all these variables. Physiological reaction such as rectal temperature, respiratory rate and cardiac rate did not vary significantly between treatments for morning recording. For afternoon recording the differences were highly significant. Sprinkling of water in T1 and T3 markedly reduced the diurnal rise in physiological norms compared to T4. The difference between T2 and T3 was comparable. Mean weekly milk yield of cows in T1, T2 and T3 increased by 4.70, 1.22 and 1.71 kg per head respectively compared with T4. Milk composition such as total solids, solids not fat, protein and fat percentages did not vary significantly between treatments. Green grass consumption differed significantly between treatments and highest in the T1 (26.16 kg per cow). Daily water consumption differed significantly between treatments and highest in the T4 (31.72 kg). Haemoglobin, packed cell volume and erythrocyte sedimentation rate differed significantly (P<0. 01) between treatments. There was a uniform loss in body weights of all the experimental cows as lactation progressed upto the peak yield stage, thereafter the cows had shown tendency to regain body weights irrespective of the type of treatment given. Sprinkling water in T1 and T3 encouraged the feeding and rumination of cows during hot hours of the day and consumed significantly more feed. Sprinkling of water in T1 and T3 increased the intensity and duration of oestrus 'and successful insemination rate. The results suggest that during the summer season of Kerala tree shade or simple shade areas with roof supported on pillors affording maximum ventilation and sprinkling or splashing of water during hot hours of the day may be practiced to alleviate heat stress and reduce drop in milk production and fertility rate during summer.