IMPACT DE LA NATURE DU REGIME, DES QUANTITES D'EAU CONSOMMEES ET DES CONDITIONS CLIMATIQUES (TEMPERATURE) SUR LES PERFORMANCES DES VACHES LAITIERES DANS LA REGION DE GHARDAÏA

Abstract

This work aims to characterize the intensity of the heat stress which are exposed dairy cows in the region of Ghardaia using the Temperature Humidity Index (THI) and study the effects of stress on production performance. In a first step, the THI index was calculated over a period of 07 months (October to April) from the mean monthly temperature and relative humidity. Thereafter, the average production performance was calculated for the same period based on data from 05 farms. The results showed the existence of a thermal stress in the region of Ghardaia from April until October with THI values ranging from 72,55 to 84,21 and beyond the critical threshold of 72 established for the Holstein cow. Daily milk production per cow decreased by 18,49% between March and April and the share (%) concentrate in the rations at the farm level vary between 45,35 and 75,60 % of energy intake an average of between 0,52 and 61,96 UFL 0,69 kg of milk from 0,60 UFL per kg milk. There is a strong correlation between THI and rectal temperature (0, 96). The amount of water drunk average is recorded in the order of 84,40 ± 6,14 l / h , and the analysis of the correlation between the parameters that influence the quantity of water consumed , shows a correlation ( 0,80 ) with the THI and (0,39 ) with the MSI .