Performance of lactating buffaloes in pasture supplemented with palm-kernel cake

Context. Palm-kernel cake (PKC) is a by-product widely evaluated as a feed additive in several species of ruminant animals. However, no information of its use in buffaloes is observed. Thus, considering the characteristics of PKC and that buffaloes are able to digest greater amounts of fibre than are other animals, it is thought that PKC can be used as a supplement for lactating buffaloes in pasture. Aims. The aim of the present study was to evaluate the effects of concentrate supplementation and the inclusion of PKC instead of conventional concentrate ingredients on the production and composition of milk, intake and nutrient digestibility of lactating buffaloes in pasture during the dry season. Methods. Five crossbred buffaloes with average bodyweight of 641.45 +/- 45.87 kg were used and distributed in a 5 x 5 Latin square-design experiment. The treatments consisted in one treatment with mineral salt supplementation (cows fed just forage; MSS control group), and four other treatments in which the cows grazed and received 3 kg/day of concentrated supplementation. The four treatments with concentrated supplementation had different inclusion levels of PKC as a supplement, which were 0%, 30.24%, 66.38% and 90.62% of dry matter (DM) replacing corn and soybean meal. A contrast between the treatment with mineral salt supplementation (MSS control group)versusthe four treatments supplemented with concentrate was analysed. In addition, to analyse the effect of inclusion of PKC in the concentrate supplement, the linear and quadratic effects were analysed by decomposing the sum of squares of each level of inclusion of PKC. Key results. There was no difference (P> 0.05) in pasture DM intake among the supplemented animals and the control-group animals (MSS). The supplemented animals (regardless of the level of inclusion of PKC) had higher (P< 0.05) fat-corrected milk production and a higher percentage of fat and lactose in the milk than did the MSS control-group animals. The intake of the supplement, crude protein and total digestible nutrients showed a decreasing linear effect (P< 0.05) with the inclusion of PKC. The daily milk production showed a decreasing linear effect (P< 0.05) with the inclusion of PKC in the concentrate. Conclusions. Concentrate supplementation for lactating buffaloes in pasture increases the amount of fat in the milk and the production of energy-corrected milk. The inclusion of PKC in concentrate supplement, replacing corn and soybean meal, decreases supplement intake and milk production. Implications. The data suggested that PKC reduced milk solids when replacing conventional concentrate ingredients; however, PKC supplements stimulated milk yield when compared with mineral salt supplementation (MSS control group). Therefore, if the inclusion of PKC reduces feeding costs, it is an economic source of supplement to promote milk production.