Avaliação da forma de fornecimento da dieta e do processamento da palma forrageira (Opuntia fícus-indica Mill) para vacas em lactação

Abstract

The aim of the present study was to assess the feeding strategy effect and the spineless cactus processing on intake and digestibility of different nutrients, milk production and composition, urea concentration in plasma and milk, and microbial protein production in lactating Holstein cows. Eight cows with a mean live weight of 453 ± 75.8 kg, production of 14 kg of milk/day and 20 weeks of lactation at the beginning of the experiment were distributed in two 4 x 4 Latin squares based on lactation order (primiparous and pluriparous). The treatments were distributed in a factor arrangement, with two forms of cactus processing knife-chopped (KC) and fodder machine (FM) and two different feeding strategies separate concentrate (SC) and total mixed ration (TMR). The intake of dry matter (DM), organic matter (OM), neutral detergent fiber (NDF) and total digestible nutrients (TDN) was lower when the spineless cactus was chopped by knife. Neither feeding strategy nor type of spineless cactus processing affected the digestibility of nutrients; milk, protein and fat production (P > 0,05), in kg/day. Milk production average values were 14,8 and 14,6 kg/day for KC and FM spineless cactus processing, and 14,8 and 14,5 kg/day for SC and MC feeding strategies, respectively. However, fat content was lower (36 g /kg, P = 0,01) when the spineless cactus was chopped by knife. Purine derivatives and N-urea concentration were not influenced (P > 0,05) by feeding strategy and the way the spineless cactus was processed. The averages observed for efficiency of microbial protein synthesis (98.9g/kg TDN), NUP concentrations (21,3mg/dL), and MUN (18,2mg/dL) were the same for spineless cactus processing and feeding strategy. The use of forage machine is recommended to spineless cactus processing in order to maximize DM intake, and the use of total mixed ration to avoid selectivity.