Clinical Observations on Three Nigerian Zebu Cattle Breeds Following Experimental Trypanosoma Congolense Infection

Three yearling cattle of each of three major Nigerian zebu breeds, viz: White Fulani (WF), Red Bororo (RB) and Sokoto Gudali (SG) were intravenously infected with 1.5 x 106 Trypanosoma congolense and monitored until the PCV declined to ≤ 15%, when they were treated with diminazene aceturate. Two cattle of each breed served as uninfected controls. Parasitaemia, which ranged between 1.0 x 103 and 5.0 x 105 trypanosomes/ml, was significantly (P<0.05) higher in SG and RB than in their WF counterpart. Signs of trypanosomosis became apparent before detection of parasitaemia, 7 to 10 days post infection (pi) firstly in SG, then RB and lastly in WF. The infected animals were dull, lagged behind the herd, had depressed appetite and pale mucous membranes. The live weight gains of infected cattle were significantly (P <0.05) lower than those of non- infected cattle. Live weight loss was least in WF (5.2%), intermediate in RB (6.5%) and highest in SG (10.3%) at 35 days pi. Of the three infected SG, two died at a mean of 28.0+14.1 days pi, while the third was treated 38days pi. Infected RB and WF were treated at a mean of 39.3+2.3 and 54.7+2.3 days pi, respectively. No infected RB or WF died before chemotherapy. It was concluded that of the three cattle breeds studied, the WF was the least susceptible to trypanosomosis, while SG was the most susceptible. Trois bovins âges d’un an, selectionnes chacun dans les trois grandes races de zebus nigerians, a savoir Fulani blanc (FB), Bororo rouge (BR) et Sokoto Goudali (SG), ont ete infectes par voie intraveineuse avec Trypanosoma congolense a raison de1,5 x 106 et surveilles jusqu’a ce que la valeur d’hematocrite ait diminue a ≤ 15%, et ils ont ensuite ete traites avec l’aceturate de diminazene. Deux bovins de chaque race ont ete utilises comme temoins non infectes. La parasitemie, qui variait entre 1,0 x 103 et 5,0 x 105 trypanosomes / ml, etait significativement (P <0,05) plus elevee chez les races SG et BR par rapport a la race FB. Les signes de trypanosomose sont devenus evidents avant la detection de la parasitemie, 7 a 10 jours post-infection (pi) d’abord chez les SG, puis chez les BR et enfin chez les FB. Les animaux infectes etaient faibles, trainaient derriere le troupeau, avaient peu d’appetit, et leurs muqueuses etaient pâles. Les gains de poids vifs des bovins infectes etaient significativement (P <0,05) inferieurs a ceux des bovins non-infectes. La perte de poids vif etait moindre chez les FB (5,2%), intermediaire chez les BR (6,5%) et plus elevee chez les SG (10,3%) a 35 jours pi. Des trois SG infectes, deux sont morts a une moyenne de 28.0+14.1 jours pi, tandis que le troisieme a ete traite 38 jours pi. Les BR et FB infectes ont ete traites respectivement a une moyenne de 39,3+ 2,3 et de 54,7+2,3 jours pi. Aucun bovin BR ou FB n’est mort avant la chimiotherapie. Il a ete conclu que des trois races bovines etudiees, la race FB etait la moins sensible a la trypanosomose tandis que la race SG etait la plus vulnerable a la maladie. Mots-cles : Bovins zebus; Sensibilite; Trypanosoma congolense; Signes cliniques