OBJECTIVE Production of the appropriate pattern of gonadotrophin levels is crucial to proper functioning of the female reproductive system. We aimed to establish whether the pituitary has invariant secretory characteristics when isolated from in vivo controls. We aimed to obtain information during both the rising and declining phases of the gonadotrophin surge. DESIGN This study investigated ...

A dose determination study for the prostaglandin analogue cloprostenol was conducted in the Red Sokoto Does (RSD). 24 RSD were divided into four groups of 6 animals, the first group is the untreated control receiving 0μg of the cloprostenol. The second, third and fourth groups were given 50μg, 75 μg and 100 μg of the drug respectively. No oestrus response was observed in the control. All the an...

The seasonal incidence of gastro-intestinal helminths and of Oestrus ovis was determined by slaughter of successive groups of 4 tracer lambs, each exposed on pasture for 33 days. Haemonchus contortus was present from March 1979 to early July 1979, with a generally increasing percentage of 4th stage larvae in each successive month. A "spring rise" in the egg count was seen in flock sheep in Octo...

This paper addresses detection of oestrus in dairy cows using methods from statistical change detection. The activity of the cows was measured by a necklace attached sensor. Statistical properties of the activity measure were investigated. Using data sets from 17 cows, diurnal activity variations were identified for the ensemble and for the individual cows. A diurnal filter was adapted to remov...

Mature bovine oocytes were activated with 7% ethanol followed by cytochalasin B or D treatment. Most oocytes extruded a second polar body and formed one pronucleus when treated with 7% ethanol alone [35/43 (81%)]. With ethanol followed by cytochalasin B or D, overall activation frequency was 70% (309/441), with activated oocytes containing two pronuclei. The cleavage rate was not significantly ...

By using cytophotometry, Fautrez (1966) and his colleagues have shown in a variety of hormonal receptors (i.e. thyroid, adrenals, ovary and vagina) that specific stimulation leads to an increase of Feulgen-measured DNA within the nuclei of target cells. According to these authors, this phenomenon is not necessarily related to an enhanced mitotic rate but would witness to a hormonedependent meta...

The fertility (positive ultrasound scanning 60-75 days after insemination) of ram spermatozoa frozen in Tris- or zwitterion/glucose/egg yolk/glycerol-based diluents was examined during the natural breeding season (autumn). In Experiment 1 Tris-citrate, high glucose and Hepes-NaOH diluents were used and ewes (n = 266) were inseminated (induced oestrus) with 20 (uterus) or 180 (cervix) million mo...

The authors investigated whether melatonin concentrations vary between the two jugular veins and whether absolute (nocturnal) or relative (nocturnal/diurnal ratio) plasma melatonin concentrations are associated with seasonal reproductive activity measured by oestrus or ovulatory activity in Payoya goats. Thirty-two adult Payoya goats were penned under natural photoperiod. Oestrus activity was t...