Energy consumption effects during early pregnancy on embryo survival and serum progesterone and oestradiol concentrations in ewes
1994
Bizelis, A.J. | Deligeorgis, G.S. | Rogdakis, E. (Agricultural Univ., Athens (Greece). Dept. of Animal Breeding and Husbandry)
The 235 mature karagouniko ewes used in this study were mated with entire rams at a synchronized oestrus and, on days 0-14 after mating, the ewes were placed in a feed lot and fed daily a low or a high ration (25% or 110% of maintenance, respectively). Blood samples were taken from all the animals on days 4, 8 and 12 after mating for progesterone determination. Ovulation rate was assessed by laparoscopy in 170 randomly selected ewes and additional blood samples for progesterone and oestradiol were also collected from 90 of the above ewes on -2, -1, 0, 1, 2, and 3rd day. Plan of nutrition had no influence on pregnancy rate. Ewes fed low rations after mating had increased progesterone concentrations. Pregnancy and ovulation rate affected also peripheral progesterone level. Embryo losses are associated with low progesterone and possibly with high oestradiol levels. Restriction of energy intake during the first two weeks of pregnancy had also resulted in higher values of progesterone concentrations four days after initiation of feed restriction but it had a very limited effect on embryo losses.
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