Showing papers in "Animal Reproduction Science in 1985"

TL;DR: A single intramuscular injection of 5 μg of an agonist of gonadotrophin releasing hormone (Hoe 766) on plasma concentrations of LH and progesterone, and on oestrous cycle length in normally cycling dairy cows changed the distribution of cycle lengths, the average cycle length and the incidence of ovulation without detected oestrus.

TL;DR: From the present study it is obvious that i.v. administered endotoxin can influence the life-span of the corpus luteum, which is probably mediated by induction of synthesis and release of PGF 2α .

TL;DR: Differences in endocrine status prior to mating were not associated with differences in luteal function after mating, as measured by circulating progesterone levels, however, mean progestersone levels were higher in ewes on a low intake after mating compared with those on a high intake.

TL;DR: The fertilizability of extrafollicular bovine oocytes cultured in vitro and transferred in either the rabbit oviduct or glass test tubes were investigated and the maturation rates of these oocytes were significantly increased.

TL;DR: Twenty-seven adult rams were raised under natural photoperiod and were trained to serve into an artificial vagina and had no significant effect on semen volume, motility and percentage dead or abnormal cells.

TL;DR: Reduced ovum quality appears to be the major cause of the lower fertility in naturally ovulating ewe lambs compared with adult ewes following natural oestrus.

TL;DR: It is concluded that progestagen pretreatment is an efficient technique to control buck-induced short ovarian cycles and restored the normal lifespan of corpora lutea compared to untreated females.

TL;DR: In this article, the authors investigated the endocrinological variations induced in anestrous goats by means of different hormonal stimulations and found that fluorogestone acetate alone alone alone was insufficient to induce either behavioural estrus or variations in the endocrine pattern.

TL;DR: The results of these three trials suggest that the release of luteinising hormone associated with an injection of a low dose of Hoe 766 produced an effect on the CL which modified the induced luteolysis.

TL;DR: Progesterone secretion was not related to ovulation rate and number of embryos during this sampling period, and a negative correlation was observed between the increase in progesterone concentration observed 2 days after the beginning of treatment and the percentage of transferable embryos collected.

TL;DR: Differences in photoperiodic control of reproduction in short-day and long-day breeding mammals are compared and evidence is presented to raise the possibility thatphotoperiod-independent rhythms in reproduction exist.

TL;DR: The spontaneous motility of pig oviducts could be fully restored after total abolition of activity by addition of PGF2α, but not of noradrenaline, which only increased the tonus of the inhibited preparations.

TL;DR: The composition of the phospholipid-bound fatty acids in the spermatozoa of the turkey, Meleagris gallopavo, and fowl, Gallus domesticus, was studied and the significance of the findings in relation to the origin of the semen collected in these gallinaceous birds was discussed.

TL;DR: The individual influence of suckling, feed supplement, season of calving, age or parity and breed on postpartum resumption of ovarian activity and uterine involution was studied using 79 White Fulani and 15 Sokoto Gudali cows.

TL;DR: It is concluded that cranial presentation with forelegs stretched in all joints is the most optimal (however infrequent) presentation in lambs at birth.

TL;DR: Neither oestrous period nor breed affected ovulation rate, and live weight and body condition score at mating, post-mating live-weight change and Ovulation rate had no effect.

TL;DR: Several of the unrestricted stags showed biannual rhythms of testosterone, prolactin and food intake accompanied by additional cycles of coat development and antler growth, considered to be due to the stags being stimulated by a particular day-length irrespective of whether it is decreasing or increasing and that plane of nutrition may influence the control of phase blockers.

TL;DR: Cows with retained placenta subsequently had longer postpartum intervals to first ovulation and more uterine infections, foot problems and mastitis than cows without retained Placental retention.

TL;DR: The effect of wastage during pregnancy was consistent across flocks and suggests that at high ovulation rates the increased probability of prenatal deaths is associated with a reduction in birth weights of lambs born in the resulting litters.

TL;DR: Nutritional stress appears to be the main cause of low reproductive rates and of the seasonal pattern of births and mitigation of this stress would lead to higher calving percentages.

TL;DR: Bovine oocytes removed from 2–6-mm follicles were matured in vitro for 20 h at 33, 35, 37, 38 and 39°C and showed very bright and uniform fluorescence within cells, which decreased proportionally to increased culture temperatures.

TL;DR: Ram spermatozoa were incubated for 12 h at a concentration of 1-5 × 106 ml-1 in a modified BWW medium with TRIS and a variety of pre-treatments and no differences were seen in % ARS between the various protein supplementations, although serum promoted significantly better survival.

TL;DR: Determinations of plasma LH concentrations over an 8-h period on days 6 and 10 post-partum indicated that there was a tendency for GnRH-treated cows to have higher levels of LH on these days, and the injection of a small dose of GnRH twice a day advanced the time of first ovulation in dairy cows by 10 days.

TL;DR: Plasma testosterone levels were estimated in different male goat age groups in Black Bengal, Beetal, BeetAl × Black Bengal and Black Bengal × Beetal at 6 months and > 12 months and genetic group differences were not significant.

TL;DR: It was concluded that mating had a direct and adverse effect on the testicular size of rams which appears to be accelerated by the sudden decrease in liveweight often experienced by paddock-mated rams.

TL;DR: During reproductive quiescence, apart from a rapid decrease in total protein content, there was a 2–3 fold decrease in the activity of certain enzymes in the seminal plasma of red deer stags, probably due either to ageing of the spermatozoa, accumulated in the epididymis, or to changes in the permeability of cell membranes.

TL;DR: The postpartal ovarian activity was studied in healthy cows and in those affected by subclinical fatty liver disease and subclinical primary ketosis, with progesterone profiles indicating three regular ovarian cycles with normal hormone levels within 70 days postpartum.

TL;DR: It is concluded that the use of this progestagen to delay parturition upset the synchronisation of endocrine events at farrowing, resulting in an increased duration of Parturition in these animals.

TL;DR: The absence of divergence of reproduction indices between the two groups suggests that the difficulty in serving maiden ewes is due to their lack of reproductive experience which does not influence their reproductive capacity.

TL;DR: A highly significant difference was established between breeds with respect to progesterone levels before and after PGF2α injection, possibly due to a seasonal effect on progestersone production in the two types of cow.