Abstract
The aim of this paper was to use the Cornell Net Carbohydrate and Protein System (CNCPS), that reports diet energy and protein value and animal requirements, as net energy for lactation ($NE_1$) and metabolizable protein (MP) respectively, to evaluate some rations for lactating Italian Mediterranean buffaloes. The investigation was carried out on six farms in the province of Caserta (southern Italy), where the milk production was controlled four times monthly on 10 animals (changing every time) chosen at different lactation days (5 categories): <2 months (A), 2-4 months (B), 4-6 months (C), 6-8 months (D), >8 months (E). Milk fat and protein were determined. Diet $NE_1$ and MP were estimated with the CPM-Dairy program (1998) using diet component chemical characteristics; then energy and protein intakes were estimated. $NE_1$ and MP requirements were estimated with two methods: 1) using CPM-Dairy that considers produced milk, fat and protein content, lactation phase and body condition score as main factors; 2) by applying the theory that to produce 1 kg of energy corrected milk, the buffalo needs 3.56 MJ of $NE_1$ and the efficiency to convert the absorbed aminoacids into milk protein is lower than cow (CNCPS). As regards energy, with method 1 the requirements were satisfactory starting from category A (4 out of 6 farms) and category B (5/6 farms); however, a surplus resulted for category E (5/6 farms). With method 2 a deficit in category A (5/6 farms) and B (3/6 farms) was observed, while the energy requirements were satisfied for all categories except E, where on only one buffalo farm had a surplus of energy intake. As regards protein, with method 1 the requirements were substantially satisfied for all the categories except E (3/6 farms); with method 2 the MP trend was much less favourable than with method 1. Indeed, a protein deficit was observed for all animals in categories A and B (5/6 farms). Moreover, on one farm the protein intake never satisfied animal requirements. In our experimental conditions, the use of the CNCPS to characterise diets for lactating buffalo and to calculate their requirements led to satisfactory results. By contrast, we cannot say the same for method 2, which applies a lower use efficiency of NE and MP for lactation in buffalo compared to cow.