Influence of season and housing on ovarian activity of indigenous goats in Zimbabwe.

Progesterone profiles were monitored in goats housed in single (n = 9) or group (n = 14) pens during winter (JJA) and spring (SON). Normal cycles (n = 97) were < or = 30 days. Extended cycles (n = 45) were > 30 days and, except for one cycle with a persistent corpus luteum, had periovulatory periods of 10 to 20 days (n = 29) or averaging 65.1 days in length (n = 15), mostly characterised by recurrent oestrus and/or occasional transient rises in progesterone. The proportion of normal cycles occurring in winter was 87.5% (28/32) and 77.7% (42/54) for goats in single and group pens respectively, falling to 62.5% (15/24) and 37.5% (12/32) respectively in spring. The distribution of normal vs extended cycles according to season was significant (P < 0.05, single; P < 0.001 group pens). Goats housed communally experienced a greater fall in the percentage of normal cycles in spring, possibly due to increased stress associated with group feeding. Within each season, however, housing per se did not influence the distribution of normal vs extended cycles. For normal cycles, Harvey's Analysis of Variance showed that season was significantly associated with length of the periovulatory period (3.99 days (JJA) vs 5.79 days (SON); P < 0.001), oestrus detection rate (87% (JJA) vs 55% (SON); P < 0.01) and oestrus duration (1.94 days (JJA) vs 1.13 days (SON); P < 0.05). In contrast, luteal phase length was not affected by season, but was significantly associated with housing (16.93 days (single pens) vs 18.32 days (group pens); P < 0.01). The reduction in ovarian activity observed in spring may reflect a seasonal reduction in fertility, possibly linked with increasing temperature and photoperiod.

Plasma progesterone concentrations during pregnancy and pseudopregnancy and onset of ovarian activity post partum in indigenous goats in Zimbabwe.

Eight pregnant does were housed individually and fed a hay and concentrate diet throughout pregnancy and lactation. The mean gestation period was 146.7 +/- 3.0 days, with a twinning rate of 75 per cent. Mean body condition scores improved from 2.4 +/- 0.2 to 2.8 +/- 0.2 over the first 80 days of gestation and were maintained at 2.8 until 45 days before kidding. From then until kidding, mean scores fell to 2.2 +/- 0.2. Plasma progesterone concentrations during pregnancy rose significantly from 3.91 +/- 0.51 ng/ml on day 40 to 5.96 +/- 0.51 ng/ml on day 60 (P < 0.05) and remained high until 5 days before kidding. Three pseudopregnant does had similar progesterone profiles to pregnant does over the first 80 days, but the rise around day 35 to 40 was not significant and progesterone concentrations returned gradually to basal levels after day 100. The same 8 does, together with an additional 4 does which had been brought inside 60 to 70 days before kidding, were used to study onset of ovarian activity post partum. The twinning percentage was 83 per cent. Mean body condition score at parturition was 2.2 +/- 0.1. By day 35 post partum, mean condition scores had fallen to 1.9 +/- 0.1, and mean weights from 36.9 +/- 1.9 kg at kidding to 32.1 +/- 2.0 kg. Ovarian cyclicity was resumed just before mean scores and weights started to improve. The mean interval from kidding to onset of oestrous cycles was 97.3 +/- 9.5 days. This coincided with mean time to weaning which was 99.5 +/- 5.5 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Idiopathic septic gonitis in five Holstein-Friesian heifers.

Five cases of gonitis in young cows are reported. In all cases lameness was severe with no weight bearing on the affected limbs. The joints were swollen. No organisms were isolated from the fluids aspirated from the joints but cytological examination showed large numbers of neutrophils, and biochemical analysis showed increases in the activities of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and lactate dehydrogenase.

Massive obstructive urolithiasis in a bull used for artificial insemination.

A seven-year-old Jersey bull used for artificial insemination showed clinical signs of obstructive urolithiasis. This was confirmed by catheterisation and subsequent urethrotomy over the site of obstruction distal to the sigmoid flexure. Although urine flow was elicited after removal of the calculi, this was only temporary and the animal had to be killed 24 hours later. On post mortem examination about 2 kg of round, smooth, pearl-like calculi were found in the urinary bladder and the urethra of the sigmoid flexure was studded with similar calculi. It was concluded that urethrotomy at the sigmoid flexure or penectomy post scrotally would not have alleviated this condition.

Effects of cobalt deficiency on the ovarian function in the East African short-horned goat.

24 normocyclic East African short-horned goats were made vitamin B12-deficient through feeding cobalt-deficient Rhodes grass (Chloris gayana) hay. The deficiency was confirmed by controls of the blood level, by the occurrence of anaemia, by increased cortisol levels, and by hypertrophy of the fasciculata and reticulata zones in the adrenal cortex. The oestrogen level increased initially, and then decreased markedly from the 3rd cycle on, and reached levels below those of the control. Ovulations finally ceased. It is suggested that ovarian dysfunctions during vitamin B12 deficiency are caused by changes in the endocrine profile.

The influence of cobalt/vitamin B12 deficiency as a "stressor" affecting adrenal cortex and ovarian activities in goats.

Twenty 1.5 to 2-year old goats were made vitamin B12 deficient by feeding them cobalt-deficient diets for 23 weeks in order to determine the effects of a progressive deficiency on ovarian and adrenal cortex activities. At 1-day intervals, blood samples were collected for haematological study and plasma for vitamin B12, progesterone and corticosteroid radioimmunoassays. At 23 weeks, the adrenal cortex was taken for histological measurement and the pituitary gland and corpus luteum for LH and progesterone determinations, respectively. The regularity of the oestrous cycles was studied using teaser bucks. The goats receiving a cobalt-deficient diet presented irregular oestrous cycles (22.6 +/- 0.8 days; maximum deviation: 12 to 38 days), while those of the controls were 18 +/- 0.3 days (maximum deviation: 16 to 21 days). Low vitamin B12 concentration led to macrocytic and normochromic anaemia. The concentration of plasma progesterone augmented, but it decreased during the third and subsequent cycles in cobalt-deficient goats as compared to the controls. Plasma corticosteroids were persistently high in cobalt-deficient goats as compared to the controls, and pituitary LH was low in the deficient goats. It is suggested that an erratic endocrinological control mechanism led to irregular cycles, the action site being located in the hypothalamo-pituitary axis.

Identification of Ehrlichia canis in East Africa.

Ehrlichia canis, the causative agent of canine ehrlichiosis or tropical canine pancytopaenia (TCP) has been identified in Kenya. Transmission studies to two dogs resulted in signs of ehrlichiosis including marked thrombocytopaenia, pyrexia, reduction in the packed cell volume and the presence of E canis in peripheral blood mononuclear cells.