Effect of slaughter weight on the carcass value of young crossbred ('Polish Holstein Friesian' x 'Limousin') steers and bulls

Apart from others factors, carcass quality is determined by the animal's age and body weight (BW) at the end of the fattening period. The aim of this study was to determine the optimum finishing weight of young crossbred 'Polish Holstein Friesian' (PHF) x 'Limousin' (LIM) steers and bulls, based on their slaughter value. The experimental materials comprised 60 animals, including 30 bulls and 30 steers, fed farm-made feeds. At 2 or 3 wk of age, one half of calves were castrated. Bloodless castration was carried out using a rubber elastrator. Calves were reared under a conventional system, and were fattened semi-intensively. Daily gains ranged from 800 to 950 g. Calves were fattened to 450, 500, 550, or 600 kg BW. Carcass value was estimated after slaughter. Fatty acid profile was determined by gas chromatography in fat extracted from samples of muscle longissimus dorsi (MLD). Bulls, compared with steers, were characterized by a higher slaughter value, including a higher carcass dressing percentage by 1.07-2.60%, higher carcass conformation, and lower carcass fatness. In steers, an increase in live BW was accompanied by a considerable increase in fat content (higher than bulls), as confirmed by a significant (p <= 0.01) interaction. The intramuscular fat of bulls was characterized by higher concentrations of fatty acids delivering health benefits, and a more desirable polyunsaturated fatty acids/saturated fatty acids (PUFA/SFA) ratio. Fat from bulls contained higher levels of PUFAs by 2.34 g 100 g(-1) on average. Semi-intensive fattening of PHF x LIM bulls to slaughter weight of 600 kg BW is recommended due to an increase in carcass value. Steers should be fattened to slaughter weight of 500-550 kg BW to prevent excessive fat deposition.