Pulses as unique concentrate for dairy cows

Abstract

Two "complete" balanced diets, one based on maize silage, providing the energetic content of a classic control concentrate feed (1 UFL/kg dry matter and 115 PDIE/UFL) and an experimental concentrate based on pulses, were given in limited quantities and compared. Nutritive values (UFL-PDI) were predetermined in order to satisfy (without excess) the requirements of the animals. According to an experimental scheme consisting of two 7 week periods, a total of 21 lactating cows (80 % first lactation) divided into two groups received one or the other of these diets. For an average content of 5.4 kg dry matter of control concentrate or of 4.6 kg dry matter of pulses, the total dry matter intake were identical (3.08 kg dry matter per 100 kg live weight). The energetic contents were comparable (15.6 UFL/day) and those of PDI were rather less for the pulse diet. The energy balance was slightly in surplus, especially for the experimental treatment (+ 0.7 UFL). Conversely the PDI balances were deficient, in particular for the pulse diet (- 130 g as compared to - 55 g for the control). For both treatments, milk production, fat output and protein output were comparable and on average : 23.5 kg, 948 g and 692 g/day respectively. Milk composition was also identical but protein contents were low with respect to the fat content (30 as compared to 41 g/kg respectively). However, the most productive cows had a decrease in milk 4 % production (P < 0.07, fat output (P < 0.02) and fat content (P < 0.02) when they received the pulse diet. In conclusion, it is possible to valorize large quantities of pulses up to production levels of 25 to 30 kg of milk per day. To achieve an increase in production, it is necessary to supplement the diet with quality protein.