EFFECTS OF TRYPANOSOMA-CONGOLENSE AND NUTRITIONAL SUPPLEMENTS ON ESTABLISHMENT AND OUTCOME OF PREGNANCY IN TRYPANOTOLERANT DJALLONKE EWES

Interactions between Trypanosoma congolense and nutritional status wer e studied in 42 ewes, bred at the peak of parasitaemia after synchroni sation of oestrus. As experimental design a randomised block design wa s used with four treatment combinations (2 x 2 factors), of which two were on a restricted diet (L), the remainder on an unrestricted diet ( H) and half of each nutritional group infected with T. congolense (LI, HI), the remainder serving as controls (LC, HC). Severity of parasita emia was not influenced by supplementation and mortality rates were hi gher in the HI and LC groups, but these differences were found not sig nificant. Progesterone levels during the synchronised cycle were signi ficantly lower in the infected groups. Levels of pregnant specific pro tein B (PSPB) in pregnant sheep at days 21 and 26 were not significant ly affected by nutrition or infection, despite the tendency of a decre ase in infected groups. T. congolense clearly affected establishment o f pregnancy, as shown by lower rates of pregnancy and extended interva ls between breeding and confirmation of pregnancy, nor was there any b enefit of nutritional supplementation. Mean progesterone concentration during pregnancy, in those ewes which lambed, was not different betwe en groups. The effect of the T. congolense infection on the outcome of pregnancy was not clear with the LI and HC performing well and poor p regnancy outcomes in groups HI and LC, although differences in litter size might explain these anomalies. It is concluded that the most pron ounced effect of T. congolense was a negative influence on establishme nt of pregnancy, with nutritional supplementation unable to overcome t his effect but having a beneficial influence on maintenance and succes sful outcome of pregnancy. However, individual exceptions indicate tha t same ewes cope better with thr negative effects of infection and poo r nutrition. (C) 1998 Elsevier Science B.V.