Experience of MOET with Welsh Black cattle in a group breeding scheme.

The embryo production records of 27 Welsh Black cows in a multiple ovulation and embryo transfer (MOET) program were examined. Significant monthly variations in the number of viable embryos recovered (P=0.07) and in embryo viability (P=0.002) were detected, although ovarian responses did not vary. Embryo recovery was not affected by the type of catheter used or by the side of the uterus flushed.

The digestibility of amino acids in the small intestine of the sheep.

1. The digestibilities of microbial and food proteins in the small intestine were studied in three sheep fitted with re-entrant cannulas in the proximal duodenum and terminal ileum. 2. The quantities of microbial and food proteins at the small intestine were varied by infusion of a microbial isolate or by dietary manipulation and the balance of amino acids along the small intestine was determined. 3. A mean value of 0.69 for the apparent digestibility and 0.86 for the true digestibility of total amino acids was obtained. 4. From the composition of digesta at the duodenum the daily flows of microbial and food proteins were estimated. Their true digestibilities in the small intestine were calculated by regression and found to be: microbial protein 0.87 and food protein 0.82. The mean endogenous loss of amino acids secreted into the small intestine was estimated to be 13.3 g/d.

The absorption of magnesium from the forestomachs, stomach and small intestine of sheep.

The passage of magnesium from the mouth to the proximal duodenum and from the proximal duodenum to the terminal ileum was measured continuously in two rams for 24 and 19 days. The results indicate a net disappearance of 25 per cent and 34 per cent of ingested magnesium from the forestomachs and stomach, and no set absorption from the small intestine.

The effect of glucose infusion on the plasma free amino acids in sheep.

1. Glucose in solution in saline, or saline alone, was administered to a group of twenty ewes during late pregnancy and again after lambing. Sequential blood samples were taken before and after the infusion and the concentration of plasma free amino acids was determined. 2. The effect of glucose was to reduce the concentrations of all amino acids except alanine. The reduction was greatest for tryptophan in the pregnant sheep, but this amino acid showed no significant change in the lactating animals. 3. An attempt to rank the amino acids on the basis of their response to glucose infusion indicated that, with the exception of tryptophan for the preparturient ewes, groups of essential amino acids could not be distinguished from each other. These groups were, for the preparturient sheep, valine, leucine, phenylalanine and isoleucine, and for the postparturient animals, isoleucine, lysine, methionine, valine and phenylalanine.