Changes in embryo production results and ovarian recrudescence during the acclimatisation to the semiarid tropics of embryo donor Holstein-Friesian cows raised in a temperate climate.

摘要: Pregnant Holstein-Friesian (HF) heifers were transported from central Europe (defined as temperate conditions) to north-eastern Brazil tropical, semiarid conditions). They kept in open-sided pens with a hard floor, roof for shade and sprinkled water 10 min every hour if ambient temperature exceeded 30 degrees C. Their diet was balanced meet nutritional requirements they fed twice daily. Control animals randomly chosen first second lactation located on farm 25 km away receiving similar management. Imported superovulated 1996 (n=63) 1997 (n=96), compared 38 45 cows the control herd. The variates recorded were: interval post-partum oestrus; changes ovarian size activity; responses superovulation; and, embryo quality. average daily milk yields of imported 20.0 23.3 l 1997, respectively 22.1 throughout experiment anoestrus 112.1+/-30.5 days 55.0+/-18.0, 48.2+/-12.0 42.6+/-10.7 cows. functionality ovaries lowest but did not differ between other group-year combinations. These also had lower superovulatory response than terms number ovulations (6.4+/-4.3 versus 13.6+/-5.9, P<0.05) good quality embryos (1.2+/-0.9 4.4+/-2.1, P<0.05). two groups respect these characters year study. reproductive efficiency superovulation their new environment. A period approximately 1.5 years is required full adaptation.