Commencement of postpartal luteal activity in Estonian dairy cows
2000
Waldmann, A. | Kureoja, A. | Kaart, T. | Tiidla, A. | Saveli, O. (Estonian Agricultural Univ., Tartu (Estonia). Inst. of Animal Husbandry)
Commencement of postpartal luteal activity was studied in 109 Estonian Red and 124 Estonian Holstein cows belonging to two peri-urban dairy herds in Estonia. Progesterone was measured in milk by enzymeimmunoassay, and profiles were set up based on twice weekly milk sampling, starting from about one week after calving. First progesterone rise indicative for presence of luteal activity, ocurred at an avarage of 33 days (stdev =18.6) after calving. Estonian Red breed cows had shorter interval (P0.05) to postpartum luteal activity compared to Estonian Holstein cows. The interval from calving to postpartum luteal activity was affected by farm (P0.05), but was not affected by lactation. Genetic models were fitted using REML. Estimate of heritability for log-transformed data was 0.14 (P0.05). Conception to first insemination could not be predicted on the basis of the interval from calving to initiation of luteal function. The results support the heritability of the postpartum interval to commencement of luteal activity in Estonian dairy cows, however, heritability estimate was not significant due to too small number of investigated animals
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