Digestibilidade e consumo de equinos em treinamento e criados a pasto

Abstract

The livestock of horses in an important branch of agribusiness, and despite that, few studies have been conducted to evaluate feed intake and digestibility of this specie. Adequate diets requires characterization of feeds that constitute then according to digestibility and intake, because these are the main factors that reflect feed quality, affecting directly animal response, especially in productive efficiency. For this study, were used 7 mares Mangalarga Marchador, between three and five years old, with average weight of 389 kg. The animals were in grazing Cynodon sp.. Dry matter intake was estimated at 2,5% body weight and roughage: concentrate proportion of 50:50. Concentrate was divided in two daily portions. The experiment took 49 days and was divided in two different periods, with the initial 42 days to adapt the animals to the diet, place and training, and the last seven days to provide the indicator and to collect feces. LIPE® was supplied to all animals, daily, directly in the mouth, for six days in a row in 0,5 grams of jelly pills, and feces collection was made for five days in a row, beginning in the third day after supply started. Preview assays showed that LIPE® is a trustful indicator for digestibility, therefore it was used in this assay as reference to compare tested indicators. To estimate apparent digestibility it was used the indicators: LIPE®, Klason lignin (LK), in acid-insoluble ash (AIA), ingestible neutral detergent fiber (iNDF) and ingestible acid detergent fiber (iADF). LIPE® was supplied to all animals as an external indicator to estimate intake, which was also estimated by Saliba & Rodriguezs formula (2009). LIPE®s estimated values for DCADM, DCAMM, DCAOM, DCACP, DCANDF, DCAADF, DCAHCEL, and DCAGE were 73,36; 67,22; 96,44; 79,77; 66,13; 66,04; 70,47; 72,03% and LKs estimated values were 91,63; 59,47; 95,67; 73,40; 55,60; 37,05; 66,00 and 67,20% respectively. Klason lignin was appropriated to estimate DCAMM, DCAOM, DCANDF, DCAADF, DCAHCEL DCAGE of grazing horses, and it is not suitable to estimate DCADM and DCACP. The indicators AIA, iNDF and iADF underestimated values of apparent digestibility in grazing equines nutrients, not being recommended for these experimental conditions. Dry matter intake estimated by LIPE® was inferior (P<0,05) than estimated intake by Saliba & Rodriguezs formula (2009). Intake values in percentage of body weight estimated by LIPE® was 0,55% higher than recommended by Nutrient (2007), which is 2,25% of body weight for animals in moderate exercise, and the estimated value by Saliba & Rodriguezs formula was 0,95% higher. LIPE®s utilization to determine grazing equines intake provides similar Nutrient(2007) recommendations, presenting potential to be used to determine intake in these specie in grazing conditions. The methodology used to determine intake, associating LK and LIPE® needs more studies.