Sixteen ewes were drawn from each of two ewe flocks, one of which had grazed on oestrogenic pastures for annual periods over the previous 5 years ("clover" treatment) while the other grazed on green oats ("oats" treatment). Fertility of ewes on the clover treatment had decreased progressively, whereas in those on the oats treatment it had remained high. Oestrous ewes were allocated alternately to receive either two or eight services then killed 24 hr post coitus and the numbers of sperm in the cervix, uterus, and fallopian tubes determined. There was no difference in ovarian activity between the two groups; however, highly significant differences were found in the numbers of sperm recovered from the cervix, uterus, and fallopian tubes. Average sperm numbers per fallopian tube were 17,160 and 350 for ewes on the oats and clover treatments respectively. In addition to the reduction in sperm numbers, both the percentage of motile sperm flushed from the cervix and the proportion of recovered ova with sperm attached to the zona pellucida were lower in ewes on the clover treatment. The results suggest that primary failure of sperm transport in ewes on the clover treatment occurred when sperm did not enter the cervix in adequate numbers following service. The significance of these observations in relation to possible causal mechanisms is discussed.

An experiment, using a total of 320 Merino ewes, over two successive breeding seasons was conducted to investigate the separate effects of energy-yielding and protein-yielding nutrients on ovulation rate in sheep. The available energy-yielding or protein-yielding nutrients in the blood of sheep fed a maintenance pelleted ration were increased by either intravenous infusions of metabolites (acetate, glucose or acetate + glucose), feeding lupin grain, modification of the pattern of rumen fermentation to increase propionate production using the ionophore, lasalocid, or by feeding of ruminally undegradable protein (formaldehyde-treated casein). All treatments were given for 9 days prior to and including expected time of ovulation. Ovulation rates were measured by laparoscopy. In the first season (the 1984 experiment) when the effects of lupin grain, glucose + acetate and formaldehyde-treated casein were compared, ovulation rates were increased significantly in the group fed lupin (29%, P less than 0.001) and the group infused with glucose + acetate (24%, P less than 0.01). There was an apparent (17%) but statistically non-significant increase in the group fed casein. In comparisons between lupin grain, glucose, acetate, glucose + acetate, formaldehyde-treated casein and lasalocid in the 1985 experiment there were similar significant increases in ovulation rates in the groups fed lupin, and those infused with glucose or glucose + acetate (approximately 25%, P less than 0.001). The increase in the group infused with acetate was lower at 14% (P less than 0.05) and the increases of 7% in the groups fed casein or lasalocid were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Summary. Two split-plot factorial experiments are described, the first with 72 entire cyclic ewes and the second with 80. The pattern of transport of spermatozoa through the reproductive tract was studied, following treatments with progestagen and oestrogen or with oestrogen alone during 2 weeks preceding insemination. A daily dose of 25 \ g=m\ g oestradiol-17\g=b\ administered to ewes for 14 days preceding oestrus had a deleterious effect on the passage of spermatozoa through the cervix into the uterus within the first 2 hr after insemination. The numbers of spermatozoa recoverable from the cranial region of the cervix 2 hr after insemination appeared to be related to the numbers in the oviducts at 24 hr. These numbers were related to fertility data from an earlier experiment using similar treatments. The data for log numbers of spermatozoa recoverable from the cervix formed a near-normal distribution and so were suitable for formal statistical analysis. There was an interaction between progestagen and oestrogen influence before mating on the pattern of sperm transport through the cervix.

Summary. Lupinosis was induced in Merino ewes by subcutaneous injections of phomopsins. Liver damage and impairment of liver function was measured by increases in plasma activities of glutamate dehydrogenase and gamma glutamyl transferase, plasma concentrations of bilirubin, and plasma clearance of bromosulfthalein. The wool growth of the ewes during and after exposure to phomopsins at different periods relative to mating was measured, and the impact of lupinosis on annual wool production assessed. Phomopsin administration decreased the length of staple grown during, and for at least 6 weeks after, exposure to phomopsins. Mean fibre diameter of wool grown during this time was also reduced. Annual wool production of the ewes was affected by exposure to phomopsins, with effects noted on fleece weight, yield, fibre diameter, strength and position of break. These effects were minor and varied between experiments. The adverse effects of reproduction on annual wool production were more significant than those of phomopsins.

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