The fattening of cull cows in mountain conditions

Abstract

118 cows (86 Salers breed and 32 Limousine breed) were studied at INRA experimental farms in Marcenat (Cantal) and Laqueuille (Puy-de-Dbme) to determine best conditions for fattening cull cows with hay diets. Hay of variable food value (organic matter digestibility between 58.5 and 64.0) was collected in fine weather conditions on the lower mountain slopes (1 000 m). The date of slaughter was fixed by reference to the average degree of fattening (a score of 3.5 - 4.0 out of 5). The Salers cows (initial average score : 2 to 2.5) produced carcasses weighing 350 kg approximately after 55 to 60 days of fattening through dietary intake of 2.0 to 2.2 kg DM/100 kg live weight. It was necessary to complement the diet with a minimum of 5 kg of concentrate in order to obtain large increases in weight approaching 1000 - 1100 g/day and to obtain 16 to 17 % of fat in total body weight at slaughter, i.e. between 19 and 20 % of the carcass. When the initial degree of fattening is lower, a prolongation of fattening did not modify the average growth in one group of cows and led to carcasses of comparable degree of fattening and weight. Twelve extra days of fattening were needed for an initial difference of 0.8 points. In a similar way, reducing the amount of added concentrate to 3 kg/day prolongs the fattening period approximately by 10 days and only leads to a relatively small difference in final weight and composition of the carcasses. Under the same fattening conditions, Limousine cows had a satisfactory weight (330 kg) but unsatisfactory composition (carcass fat : 15 %). The low level of hay intake (10 % less than Salers) limits the energy available for fattening. For this type of cow it is necessary to ensure an excellent quality of basic fodder and to ensure that more than 50 % of the dietary intake is in the form of concentrate.