Características da carcaça e da carne de novilhos de origem leiteira alimentados com dietas à base de palma forrageira

Abstract

The objective of this issue was to evaluate the quantitative and qualitative characteristics of the carcass of dairy steers receiving diets based on spineless cactus and sorghum silage; the silage is associated by cottonseed meal, and the use of ultrasound to evaluate carcass of Holstein-Zebu young cattle destined for slaughter. The study was conducted at the Experimental Station of Caruaru, belonging to the Agronomic Institute of Pernambuco - IPA, located in the city of Caruaru, Pernambuco. It was used 18 non castrated steers, 5/8 Holstein-Zebu breed, with an average initial weight of 320 kg and 24 months old, approximately. The animals were confined for 84 days, divided into three periods of 28 days, housed in individual pens equipped with feeders and drinkers. To obtain ultrasound images it was used an Esaote Europe Aquila Vet equipment, with the transducer of 18 cm in length, coupled with acoustic guide to better fit the anatomy of the animal and frequency of 3.5 MHz. Ultrasound measurements were taken from loin eye area (LEA-US), subcutaneous fat thickness (SFT-US) and rump fat thickness (RFT-US), which were correlated with the weights of the front and back, and the yield of the back. Were also performed correlations between measures of LEA and SFT measured by ultrasound in the carcass. After slaughter, it was recorded the hot carcass weight, the weight of the haunches, the length of carcass, leg and thigh. The meat quality was assessed by the ultimate pH, color, cooking loss, the water holding capacity and shear force. It was performed the estimation of carcass composition by separating the tissues that make up the section between the 9th and 11th ribs (HH section). The effects of experimental diets did not differ, showing that spineless cactus associated with silage and urea produced meat qualitative characteristic and quantitative carcass of Holstein-Zebu young cattle similar to the diets supplemented with cottonseed meal, except the back weight, showing carcass parameters that qualify them for slaughter. Meat from dairy steers has soft texture. The use of ultrasound for predicting the Longissimus dorsi muscle area and subcutaneous fat thickness measured between the 12th and 13th ribs provides a satisfactory accuracy.