Influence of adrenalectomy on embryonic mortality in thermally stressed ewes

Effects of an experimental Trypanosoma congolense infection on the reproductive performance of West African Dwarf goats

Thirty-six West African Dwarf (WAD) goats were used to assess the effects of an experimental Trypanosoma congolense infection on their reproductive system. Estrous cycles were synchronised and when confirmed pregnant (n = 31), the does were randomly allocated into control and trypanosome-infected groups. After infection, the animals were carefully observed till parturition. Trypanosome infection caused an increase of rectal temperature, a significant drop in PCV (infected: 23.3 +/- 0.3%; control: 28.5 +/- 0.4%; P < 0.0001) and abortions in 27.8% of the infected does. Kids born from infected does had a lower birth weight than kids born from control goats (0.9 +/- 0.1 kg versus 1.6 +/- 0.1 kg; P < 0.0001). Eight out of 13 kids (61.5%) that were born alive from infected does died during their first week of life. Plasma pregnancy-associated glycoprotein (PAG) and progesterone concentrations were lower in the infected animals than in the controls. In general, PAG concentration in does which aborted dropped before abortion. Our results revealed that artificial T. congolense infection affected reproductive performance of WAD goats with abortions, premature births and perinatal losses being observed. Neither transplacental transmission of T. congolense nor histopathological lesions of the placenta could be demonstrated.

Trypanosomosis and reproduction: II. Effect of Trypanosoma vivax infection on pregnancy and post-partum cyclicity in ewes

The effect of infection with Trypanosoma vivax on pregnancy and post-partum cyclicity in ewes was investigated. Of the 5 ewes infected in the first trimester, 3 died without aborting and 2 after aborting. Intrauterine infection occurred in 2 of the foetuses removed at post mortem. Of the 5 infected in the third trimester, one ewe died without aborting, one lambed prematurely and 3 at term. Intrauterine infection occurred in one of the lambs born at term. None of the lambs were viable. The termination of pregnancy may be as a result of stress. The ewes infected in the third trimester commenced irregular cyclicity 13 to 23 days post partum.

Effects of infection with Trypanosoma brucei brucei on different trimesters of pregnancy in ewes

The effects of Trypanosoma brucei brucei infection during the first, second or third trimesters of pregnancy in 13 ewes were studied. All infected ewes were anaemic with the anaemia being most severe, moderate and least in ewes infected in the second, third and first trimesters, respectively. Weight loss occurred in all infected ewes but was most severe in ewes infected in the third trimester. Three of the four ewes infected in the first trimester died without aborting while one aborted and later died. Of the four ewes infected in the second trimester, three died without aborting while one lambed and later died. In the third trimester ewes, one aborted, two lambed and all three later died while one died without aborting. None of the lambs was viable. The control ewe lambed normally. The infection resulted in 16.7% abortion, 100% death and 33.3% neonatal deaths. This study demonstrates that T. brucei brucei has a devastating effect on pregnancy irrespective of the trimester of infection.

Effects of adrenalectomy upon ruminant liver and mammary function during lactation

Adrenalectomized, lactating ewes treated with a mineral corticoid or a mineral corticoid plus cortisol and sham operated ewes nursing one or two lambs were in a study of physiological role(s) of glucocorticoids in lactating ruminants. Measurements of ewe and lamb weight changes; feed intake; milk yield and composition; blood potassium; metabolite oxidation rates by mammary, liver, and kidney tissue slices; glucose production in liver and kidney tissue slices; and enzyme activities in mammary and liver tissue. 1) Mammary metabolism and milk biosynthesis in ruminants are not strongly dependent on glucocorticoid. 2) Liver gluconeogenesis in ruminants appears to be regulated in part by glucocorticover and kidney of ruminants may respond differently to adrenalectomy; thus, in ruminants, kidney may not be as good an indicator of liver gluconeogenic responses as it is in rodents. 4) Liver and mammary enzymes are not affected significantly by adrenalectomy or glucocorticoid therapy. 5) Glucocorticoids play a less significant role in the regulation of liver and mammary enzyme and metabolism in sheep than in rats.