Estratégias de fornecimento de dietas à base de palma forrageira para vacas leiteiras

Abstract

This study aimed to evaluate the effects of different feeding strategies of diets based on cactus cladodes on feed intake, milk yeild and composition, nitrogen balance, microbial protein synthesis and ingestive behavior of Girolando lactating cows. Eight cows at 96.5 ± 7.6 days of lactation with average milk yield of 12.2 ± 0.26 kg day-1 were arranged in two Latin squares (4x4), balanced for residual effects, and fed a diet composed of cactus cladodes, sugarcane and concentrate. The four feeding strategies tested were: total mixed ration (TMR) cactus cladodes associated with concentrate and separated sugarcane (CC+Con/SC) and sugarcane associated with concentrate and separated cactus cladodes. (SC+Con/CC). The diet was formulated to meet the nutritional requirements of cows producing 13 kg day-1 of 4% fat corrected milk. Dry matter (DM, 13.31 ± 0.28 kg day-1), organic matter (OM, 12.27 ± 26 kg day-1), crude protein (CP, 98 ± 0.05 kg day-1), neutral detergent fiber (NDF, 4.48 ± 0.10 kg day-1), non-fibrous carbohydrates (NFC, 6.03 ± 0.20 kg day-1) and total digestible nutrients (TDN, 9.29 ± 0.50 kg day-1). The digestibility of DM (676.76 ± 30.6 g kg-1), OM (704.4 ± 28.4 g kg-1), CP (699.45 ± 49.3 g kg-1), NDF (532.25 ± 58.3 g kg -1) and NFC (854.87 ± 31.6 g kg -1) were not altered by the strategies tested. The different strategies did not influence milk yeild (12.22 ± 0.26 kg d-1), 4% fat corrected milk (13.5 ± 0.34 kg d-1), milk protein (38.97 ± 0.05 g kg-1), milk fat (47.12 ± 0.11 g kg-1), lactosis (42.7 ± 0.03 g kg -1), casein (13.27 ± 0.15 g kg-1), total solids (138.27 ± 0.15 g kg-1) and urea (10.87 ± 1.33 mg dL-1). The nitrogen balance (207.45 ± 9.82 g day-1), microbial protein synthesis (1071 ± 116 g day-1) and microbial protein synthesis efficiency (119.20 ± 2.82 g kg TDN-1) did not change between strategies. The time spent in feeding activities (274.06 ± 8.5 minutes day-1), rumination (435.31 ± 27.64 minutes day-1) and idle time (730.60 ± 35.48 minutes day-1) were not influenced by the different strategies. Animals fed with SC+Con/CC spent more time in feeding at the afternoon (12:00 h to 18:00 h). The MC, as well as the other tested strategies, are options for feeding cactus cladodes based diets without dairy cows impairment performance. The different feeding strategies did not modify the ingestive behavior of the Girolando cows fed with cactus cladodes diet.