La mortalité néonatale chez les ovins en Algérie

Abstract

In Algeria, sheep meat farming represents almost the entire sector (28 million sheep heads according to the Ministry of Agriculture and Rural Development, 2019). Whatever the production system, perinatal mortality among sheep is on average 15 to 20%. (It impacts the numerical productivity and therefore the income of sheep farmers. Lamb mortality is of infectious origin (viral, bacterial, fungal or parasitic, systemic or localized infections) or non-infectious (consequence of dystocic lambing, starvation-hypothermia syndrome, congenital anomalies, deficiency disorders, etc.) and depends of the age of the lambs. The risk factors are multiple and are either related to the mother (age/parity, litter size, maternal behaviour, nutrition and body condition of pregnant ewes, transfer of passive immunity, genetics), to the lamb (weight of birth, type of wool coat, behavior and temperature of the lamb at birth) or the environment (climatic or environmental conditions, place of lambing, health status of the herd). There are strong interactions between the different risk factors, which makes their diagnosis complex, especially in the absence of reliable recordings of lamb mortality. Complete outdoor lambing represents more than three quarters of ewes lambing in Algeria, given the semi-extensive breeding practiced in the highlands and the Sahara. The sheepfolds are made up of tents for the breeders and enclosures in the wake without a roof as stables for the sheep and goats, the ewes give birth in the open air in the middle of the other members of the herd, the intervention of the shepherd is only done when dystocic cases, in these cases he can intervene himself or lead the sheep to the veterinarian. Newborn lambs receive no special treatment, they are neither sheltered from the wind nor sheltered from the cold, temperatures can approach -6 C° in the steppe zone in November at the peak of lambing in 'fall. The lamb mortality rate at 48 hours is 24%. Under these conditions, 33.5% of this mortality is attributed to physical or biological causes relating to mothers and newborns, 38.5% to the behavior of mothers and 12% to harsh weather conditions, 16% to causes of mortality remain unknown. Two thousand six hundred eighty five ewes were used in the present study of neonatal lamb mortality. These ewes belong to eight different farms in: Sidi Ladjel, Djelfa. Ksar Chellala/ Ain D'heb, Tiaret and Fornaka, Mostaganem. These ewes were followed during their lambing periods extending from November 2021 until April 2022. The average rate of neonatal mortality recorded then for these lambs from birth to the 14th day varied between 11.42% and 41.61%. In this study, we will demonstrate the impact of this fall lambing mortality on the growth of the sheep herd in Algeria. The first hours of life of the lambs will be scrupulously dissected, highlighting the specificity of the factors influencing the percentage of this mortality and how we managed to reduce these losses which were around 40% to 7% or even 2% in certain regions using a suspension based on a local plant that we ourselves have made as a prophylactic treatment, drawing inspiration from an Irish veterinary product.