Early pregnancy diagnosis and embryo/fetus mortality in cattle

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Title: Early pregnancy diagnosis and embryo/fetus mortality in cattle
Author: Romano, Juan Eduardo
Abstract: Pregnancy diagnosis by transrectal ultrasonography (using a 5 MHZ linear probe ) presented the maximum sensitivity and negative predictive values at day 26 and day 29 after estrus in heifers and cows , respectively . Palpation per rectum using the fetal membrane slip for pregnancy diagnosis did not increase embryo /fetus mortality when compared with a positive control group of non -palpated females . The use of a controlled randomized block design was a useful approach to study this problem . Blocking for category and number of embryos allowed us to remove these confounding factors . Factors that affected pregnancy loss during the first four months of pregnancy were : period of pregnancy , age of the animal , number of previous lactations and number of embryos . Pregnancy loss was higher during the embryonic than fetal periods . Spontaneous embryo /fetal mortality increased with the age of the animal and lactation number . The risk of spontaneous embryo /fetus mortality was higher in twin than in single pregnancies . Two types of embryo /fetus mortality were noted : Type I and Type II . Type I was characterized by presence of positive fetal membrane slip by palpation per rectum , signs of degeneration by transrectal ultrasonography and persistence of a functional corpus luteum . The uterus took approximately 3 weeks to be noted clean by transrectal ultrasonography and the animals showed estrus one month after the conceptus was diagnosed dead . Type II was characterized by absence of positive signs of pregnancy by palpation per rectum , absence of signs of degeneration by transrectal ultrasonography and absence of a functional corpus luteum . Pregnancy loss in nuclear transfer derived embryos was higher compared to in vivo derived embryos produced by artificial insemination . Pregnancy loss occurred mainly during the transition from the embryonic to the fetal period . Embryo /fetus mortality detected was Type I . Progesterone produced by the corpus luteum was noted at pregnancy levels for approximately two weeks after embryo /fetus death . Protein B , a hormonal placental marker , was maintained at pregnancy levels for approximately 3 weeks after embryo /fetus death . No differences in the levels of the two hormones were noted when comparing females with dead or live conceptuses .
URI: http : / /hdl .handle .net /1969 .1 /3125
Date: 2006-04-12

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Early pregnancy diagnosis and embryo/fetus mortality in cattle. Available electronically from http : / /hdl .handle .net /1969 .1 /3125 .

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