The Repeatability of Ovulation Rate in Merino Ewes
نویسنده
چکیده
The ovaries of 3 groups of Merino ewes were examined for corpora lutea by laparoscopy every 17 days between 28.3.74 and 16.6.75. During the 1974 breeding season the mean body weight of the ewes was maintained at 37 kg. Between the 1974 and -1975 breeding seasons the nutrition of the ewes was varied to give groups of ewes with mean body weights of 37, 41 and 46 kg; groups of ewes of low, medium and high nutritional status, respectively. These groups were maintained throughout the 1975 breeding season.
منابع مشابه
Oestradiol Implant Reduces Litter Size in the Booroola Merino
The litter size of homozygous Booroola Merino ewes results in high perinatal mortality. One subcutaneous implant of crystaline oestradiol in silastic tubing in heterozygous Booroola Merino ewes decreased ovulation rate from 3.18 -r0.15 (n = 39) to 2.03 & 0.14 (n = 35), and decreased litter size (5 8 weeks pregnant) from 2.49 + 0.13 (n = 39) to 1.47 + 0.12 (n = 32), providing a useful management...
متن کاملAn Effect of Previous Nutritional Treatment on the Ovulation Rate of Merino Ewes
The expression of oestrus in ewes may be influenced by previous nutritional *history. Smith (1966) reported that restricted nutrition during the spring delayed or reduced the expression of oestrus in Merino ewes during the following autumn, even though nutrition had been improved and ewe live weights had recovered before the rams were introduced. Hunter (1962) and Smith (1962) have also suggest...
متن کاملThe Active Immunization of Sheep against Oestrone, Androstenedione or Testosterone to Increase Twinning
Procedures have been developed to produce consistent increases in ovulation rate in Merino ewes by immunization against the steroids, androstenedione, testosterone and oestrone. The procedures were based on experiments in the field over the period 1978-1981 using groups of 50 ewes for each treatment. The method uses selected steroid-human serum albumin conjugates, together with DEAEdextran adju...
متن کاملHeterotic Basis of Ovulatory and Reproductive Performance in Ewes of Three Breeds
Variation in ovulation rate of ewes was studied with particular reference to the heterosis effect in a 3-breed (Dorset Horn, South Australian Merino, Corriedale) experimental sheep population. For the population as a whole, heterosis effect on the young (1 1/2 year-old) ewes (+0.17 k 0.06** ova, or 14.5%) was similar to that on the mature (5 1/2 year-old) ewes (+0.19 f 0.06** ova, or 12.5%), in...
متن کاملSynchrony of ovulation and follicular dynamics in merino ewes treated with GnRH in the breeding and non-breeding seasons.
The effect of gonadotropin releasing hormone (GnRH) treatment on the time of ovulation and the occurrence of follicular dominance during the non-breeding and breeding seasons (experiment 1), and on fertility after artificial insemination (AI) in the non-breeding season (experiment 2), was examined in Merino ewes. Oestrus was synchronized in 40 nulliparous ewes (experiment 1; n = 20, in the non-...
متن کامل