Risk factors of lamb mortality in Pakistan

Abstract

This study was carried out to investigate lamb mortality in 528 Pak-Karakul and 423 Thalli in Pakistan during 1998-1999. Mortality was 9 and 12% in the lambs of the two breeds, respectively. In Pak-Karakul lambs, pneumonia rendered the highest morbidity and mortality and all mortalities recorded were in the first week, whereas in Thalli lambs diarrhoea was at the peak, with 82 and 18% mortalities in the first and second week of life respectively. Birth weight of neonates that died was lower (P < 0.05) than that of the lambs that had survived. The correlation revealed a positive and significant (P = 0.000) relationship between birth weights of Pak-Karakul lambs and serum Ig, total proteins and globulin concentration. In Thalli lambs such a relationship was found in serum Ig and globulin concentration. Parity of ewes and sex of lambs in both breeds did not affect mortality rates. Lambs with Ig levels less than 20 zinc sulphate turbidity (ZST) units died while those with more than 20 ZST-units survived. Dams that lost their lambs had significantly (P < 0.05) lower values of colostral Ig than those with live neonates. Serum Ig concentration in survived neonates of both breeds had significant (P = 0.000) and positive correlation with colostral Ig of their dams. lamb mortality / Pak-Karakul and Thalli sheep / risk factors / Pakistan Rsum -Facteurs de risque de la mortalit des agneaux au Pakistan. Cette tude a t ralise pour tudier la mortalit des agneaux de races Pak-Karakul (n = 528) et Thalli (n = 423) au Pakistan au cours des annes 1998 et 1999. La mortalit tait respectivement de 9 et 12 % pour les deux races. Pour les agneaux Pak-Karakul, la cause de morbidit la plus leve a t la pneumonie et tous les cas de mortalit ont t enregistrs durant la premire semaine de vie. Concernant les agneaux Thalli, la diarrhe a t l'origine du plus grand nombre de dcs, avec des mortalits de 82 et 18 % la premire et la deuxime semaine de vie, respectivement. Le poids de naissance des nouveau-ns morts tait infrieur (P < 0,05) celui des agneaux qui ont survcu. La corrlation de Pearson a permis d'tablir (P = 0,000) une relation positive et significative entre les poids la naissance des agneaux Pak-Karakul et les immunoglobulines (Ig) du srum, les protines totales et la concentration en globulines. Chez les agneaux Thalli, une telle relation a t trouve entre les Ig du srum et la concentration en globulines. La parit des brebis et le sexe des agneaux dans les deux races n'ont