Glicerina bruta na alimentação de machos de Origem Leiteira.

Abstract

Four experiments were conducted to evaluate the nutritional characteristics of crude glycerin as an alternative food in diets for ruminants and their effects on intake and nutrient digestibility, growth performance, development of the digestive tract, blood parameters and feeding behavior. Treatments consisted of the inclusion of 0, 80, 160 and 240 g of crude glycerin per kg of dry matter. All assays were conducted in completely randomized design with six replications. In experiment I 28 crossbred dairy calves with an average weight of 38.03 ± 7.2 kg and five days age housed in individual covered mobile hutches, and provided with drinker and trough were used. The inclusion of crude glycerin on concentrate influence the dry matter intake and average daily gain observing linear increase with advancing age of the calves being the inclusion of 240 g/kg led to the largest dry matter intake (DMI) and average daily gain (ADG). There was no effect on final weight and total weight gain of the animals whose averages were 73.60 and 35.16 kg, respectively. There was no effect on final weight and total weight gain of the animals whose averages were 73.60 and 35.16 kg, respectively. When the weight of the rumen/reticulum was expressed in kg/100kgBW, kg/100kgEBW and kg/100kg of the total tract, there was a linear increase with the inclusion of crude glycerin. The concentrations of total protein, globulin, urea, cholesterol, amaglutamiltransferase, aspartate aminotransferase and alkaline phosphatase did not differ between treatments. The weights of the hot and cold carcass as well as their yields, tissue composition and primary carcass cuts were not altered. In experiment II 24 calves with initial weight of 95.46 ± 11.80 kg three months of age individually penned for 104 days were used for the production of modified veal. The DMI was reduced linearly, however, there were not observed effects on nutrients apparent digestibility, ADG (1.09 kg/day), final weight (195.7 kg), total weight gain (100.2 kg) and main carcass characteristics with the inclusion of crude glycerin in the diet. The weight of the reticulo-rumen and abomasum were elevated with the inclusion of crude glycerin in the diet. The total cholesterol concentration responded quadratically at the increases in crude glycerin in the diet, while the other blood parameters were not affected. In experiment III we used 24 steers with an average initial weight of 337.3 ± 39.7 kg and 15 months of age fed during 84-day in individual stalls. The intake and digestibility of dry matter and nutrients were not change with inclusion of crude glycerin in the diet. The final weight (430.2 kg), the total weight gain and ADG were not altered with the inclusion of crude glycerin in the diet. There were no effects on hot (218.9 kg) and cold carcass weight (215.2 kg). The longissimus dorsi area (62.86 cm²), subcutaneous fat thickness (4.05 mm) and carcass qualitative traits were similar between treatments. Serum concentrations of glucose, triglycerides, total cholesterol, HDL cholesterol, albumin, urea, alanine aminotransferase, aspartate aminotransferase and creatinine were not modified, but the blood levels of total protein were reduced linearly. In experiment IV we evaluated the effects of the crude glycerin inclusion in the diet on the feeding behavior of dairy calves and steers. Behavioral observations were conducted for 24 hours recording the activities of feeding, rumination and other activities intermittently every five minutes and the characteristics of chewing, eating and ruminating efficiency beyond the frequency of drinking. For calves the time spent feeding was reduced linearly and leisure activity tended to linear increase with the inclusion of crude glycerin in the diet. The activities of rumination and other activities were not influenced by the diets, with averages of 7.00 and 4.77 hours per day, respectively. For steers, the crude glycerin in the diet promoted quadratic behavior on the time spent eating and ruminating. The shortest time feeding was 13 estimated at 83.3 g/kg of crude glycerin. The maximum rumination time was estimated with 91.4 g/kg inclusion. The inclusion of crude glycerin in the diet alters the main characteristics of animal feeding behavior.