Substituição de palma miúda por palma orelha de elefante mexicana para vacas mestiças em lactação

Abstract

A forage resource that has long been used to "sustain" dairy cattle in the northeastern semiarid region during the dry season is the palm, since the morphological characteristics of the species of the Cactaceae, CAM plants can withstand the rigors of climate and the physico-chemical specificities of the semi-arid soils. The objective of this study was to evaluate the effects of the replacement of Miúda by Orelha de Elefante Mexicana spineless cactus on nutrient intake, digestibility, milk yield and composition, ingestive behavior, microbial protein synthesis, nitrogen balance, ruminal and blood parameters, profile, production of fatty acids, enzymatic activity indexes and nutritional indexes of milk fat from Girolando cows. Ten Girolando cows 500 ± 51.6 kg of body weight were distributed in 5 x 5 double Latin square. The five experimental treatments consisted of different proportions of replacement of MIU by OEM (0; 25; 50; 75 and 100%). Intake and digestibility of dry matter, matter, crude protein and total digestible nutrients decreased linearly with substitution. Despite the decrease in intake and digestibility of DM, OM and CP, the nutrient supply was sufficient to maintain milk production of 12.5 kg/day. MIU palm replacements by OEM provided linear reduction of C12: 1 cis-9 + C: 13: 0 AG and C14: 0 AG (P <0.05). AG C15: ISO increased linearly and the C15: 0 AGs before iso and C15: 0 reduced with the substitutions. AG C16: 0 showed a linear reduction with the PMD substitutions per OEM cactus pear. The activity indexes of the SCD14, SCD16 and SCDRA enzymes had no effect (P> 0.05). However, the enzyme SCD18 reduced activity with MIU substitutions by OEM. The Orelha de Elefante Mexicana cactus pear reduces some saturated fatty acids like C16: 0 and increases other polyunsaturated ones like C18: 2. The OEM can replace 100% of the MIU in diets with 48% of forage palm for crossbred dairy cows with 12.5 kg / day of milk production promoting the same performance and without impairing the nutritional characteristics of milk fatty acids.