Freqüências do fornecimento do volumoso e concentrado no desempenho e comportamento ingestivo de vacas e novilhas em confinamento

Abstract

The present study was developed with the objective of evaluate if the frequency of roughage and supplement supply and/or animal category affect performance and behavior of feedlot cattle. Sixteen heifers and sixteen cows were used, with average initial age of 20 and 66 months and average initial weight of 338 and 462 kg, respectively. The frequencies of roughage and supplement supply were: 2 V/C roughage and supplement 2 times per day; 1 V/C roughage and supplement 1 time per day; 1 V/2 C roughage 1 time per day and supplement 2 times per day; 1 V/3 C roughage 1 time per day and supplement 3 times per day. Each food supply was offered to cows and heifers. The supplied diet was composed by 60% of maize silage and 40% of concentrate, on dry matter base (DM). The process of obtaining performance parameters was by animal weighting and attribution of body condition, weighting of the supplied food and it s respective orts, chemical analysis of diet ingredients and orts. Behavior parameters were obtained by register of animal activities at each 5 minutes, beyond counting chews per ruminated bolus and it s duration. The complete randomized experimental design was used, with a 4 x 2 factorial arrangement. No significant interaction was observed (P>.05) between supply frequencies and animal category for performance variables. For ingestive behavior, was observed interaction between supply and animal category for rumination (RT) and idle (IDT) times, efficiencies of dry matter rumination (EDMR) and neutral detergent fiber rumination (ENDFR), number of daily bolus and daily time of chews (DTC). Supply frequencies did not influence (P>.05) average daily weight gain (ADWG). Dry matter intake (DMI) per animal was superior for animal of 1 V/2 C or 1 V/3 C treatments. The DMI and digestible energy intake per animal and per metabolic size were higher for cows, however ADWG was similar (1.330 vs. 1.378, respectively), resulting on worst food conversion for cows in relation to heifers (9.4 vs. 7.4 kg, respectively). Heifers showed higher (P<.05) IDT and DTC when compared with cows that received food once in a day. Time of food intake (TFI) did not vary (P>.05) with supply frequencies. Ingestion rate (IR) was higher (P<.05) for animals that received 1 V/3 C, and did not differ from the ones that received 1 V/2 C in relation to 1 V/C and 2 V/C supply frequencies (2.89; 2.72; 2.43 and 2.48 kg of DM/hour of intake, respectively). Cows were higher for TFI and IR in relation to heifers (4.38 vs. 4.09 hours, 2.91 vs. 2.35 kg of DM/hour of intake, respectively). The frequencies supply of one, two or three times per day stimulates animals to intensify ingestion on the moment of the supply, but this don t alter time of food intake during the day and animals weight gain.