The growth rate, feed consumption and carcase composition of nine untreated wether lambs (controls) were compared with those of lambs in which a chronic pneumonia had been experimentally induced. Six pneumonic lambs (group 1) were killed with the controls on day 109 and eight (group 2) lambs were killed when they had a similar mean liveweight to the controls (42 kg) on day 172. The mean liveweight gain of infected animals to day 108 was 59 per cent, the mean feed intake 69 per cent and the mean carcase weight of group 1 was 73.5 per cent that of the controls. Group 2 lambs required 25 per cent more feed and nine weeks longer than the controls to reach similar live and carcase weights. This depression of appetite and growth rate was most marked in the first 35 days after inoculation, but growth rates of infected lambs continued to be lower than those of the controls throughout the experiment. At slaughter, all infected lambs had consolidated lesions of pneumonia and a significant correlation was noted between the extent of lung lesions and total liveweight gain in individual lambs. Carcases of group 1 lambs had a proportionately low fat, high lean meat and bone content, indicative of immature development and consistent with a lowered feed intake. Carcases of group 2 lambs showed a similar trend but differences from the controls were not significant.

A number of sheep of the Orkney breed died of suspected copper poisoning while at pasture under circumstances which left sheep of other breeds apparently unaffected. Fresh seaweed offered to sheep with symptoms of copper toxicity appeared to be therapeutic and to lead to a reduction in plasma Cu level.

A trial was devised to assess whether the administration of selenium and cobalt together with the anthelmintic mebendazole (Ovitelmin S&C) was safe and could improve the supplies of selenium and cobalt for adult sheep fed a whole grain diet, low in both elements, which produced a steady decrease in blood glutathione peroxidase (GSHPx) and plasma vitamin B12 concentrations. Ovitelmin S&C, when given orally in a single dose as a suspension containing 0.34 mg selenium/ml, and 0.44 mg cobalt/ml (to provide 0.11 mg selenium and 0.15 mg cobalt/kg liveweight) significantly increased the GSHPx activity in blood. After a second dose given 28 days later the rate of change increased from 2.5 to 3.5 u/g haemoglobin/day. The responses in GSHPx were similar for a preparation which contained twice the concentration of selenium. Ovitelmin S&C increased the concentration of vitamin B12 in the plasma by about 1000 pg/ml for four to seven days after each dose and the increases were similar to those observed in sheep treated with an Ovitelmin preparation containing 45 times more cobalt (providing 6.7 mg cobalt/kg liveweight). After 63 days, liver vitamin B12 concentrations were 43 per cent higher in the cobalt treated than in the untreated groups (P less than 0.01) with no differences among the groups given cobalt. Neither adverse reactions nor signs of toxicity followed the administration of Ovitelmin S&C or Ovitelmin containing the higher concentrations of selenium and cobalt.

No abstract

Two monotocous and two ditocous ewes were infused at 124-130 days of gestation with a mixture of L-[U-14C]lactate and D-[6-3H]glucose via a maternal or umbilical catheter, separate days being used for each infusion. Plateaux-specific radioactivities of plasma lactate and glucose were used to derive a four-pool model describing the fluxes between the lactate and glucose pools of the infused conceptus and mother. The average turnover rate of lactate was 23.3 and 13.2 mg carbon min-1 in the conceptus and 32.0 and 44.0 mg carbon min-1 in the mother for monotocous and ditocous ewes, respectively. Glycolysis rates within both conceptus and mother in all sheep were high, accounting for about 80 and 60% of the respective rates of lactate turnover. The synthesis of glucose from lactate accounted for 13 and 31% of the glucose turnover in the mother in monotocous and ditocous ewes, respectively, but was insignificant in the conceptus. Glycolysis within the conceptus used only glucose which had entered and mixed with the conceptus glucose pool; there was no direct transfer of carbon from the maternal glucose pool to the conceptus lactate pool. This finding is an important validation for the use of tracer methods to determine glucose use within the whole conceptus rather than within fetal corporeal tissues alone.