Efecto de niveles creciente de inclusión de grano de lupino (Lupinus Angustifolius) en dietas de terminación sobre la performance a corral y a la faena de novillos Hereford

The objective of this work is to evaluate the effect of the substitution level of sorghum grain for lupine grain in the diet on the performance at the corral and at the slaughter of steers in the finishing phase.The lupine inclusion levels evaluated were 0, 15, 30 and 45% of the diet. This work was carried out in the Intensive Meat Production Unit (UPIC) of the Experimental Station “Dr. Mario A. Cassinoni'' (EEMAC), University of Agronomy, located in the department of Paysandú at km 363 of Route 3. It lasted 106 days, beginning the period of confinement of the animals on 8/19/2021, ending on 12/3/2021 with their slaughter. Forty-eight Hereford steers were used, born in the spring of 2019, from the EEMAC experimental herd, which were blocked at the beginning of the experimental phase by live weight in three blocks (light, 361.6 ± 15.6 kg; medium, 392.1 ± 6.9 kg, and heavy, 416.5 ± 6.3). The corral performance variables that were worked on were; weight gain, dry matter intake, conversion efficiency, rump height, ingesting behavior, intake pattern, digestibility and physically effective fiber intake. On the other hand, in the slaughterhouse, variables related to carcass and meat quality were evaluated, such as slaughter weight, hot carcass weight, yield, pH, thickness of subcutaneous fat, muscle color, fat color, marbling and strength of meat. court. The dry matter intake ended linearly (P=0.0082) with the increase of lupine in the diet, there were differences in GMD, this being lower in the treatment with 30% inclusion of lupine. Regarding the conversion efficiency, no observed significant differences were observed at the experimental level (p=0.7911). The DMS and DMO decreased when lupin was included in the diet; these variables were adjusted to a quadratic model (P=0.0095) (P=0.0074), presenting a minimum value when the inclusion of lupin was 31.18% and 30,65% respectively. The ef% NDF was adjusted to a linear model (P<0.0001), increasing its value as the inclusion of lupine in the diet increased. During the behavior, it was observed that the intake activity presented significant differences (p=0.0018) between the control treatment and the treatments with lupine inclusion, presenting a lower intake activity by the animals fed with lupine. This explains why the animals in the 0% treatment are the ones that present less resting activity with respect to the other treatments (p<0.05). Rumination activities and water intake did not present significant differences between treatments (p=0.8077 and p>0.05, respectively). In the characteristics that make carcass quality there were no differences between treatments, in meat quality characteristics, the cutting force was adjusted to a linear model (P=0.0408), the inclusion of lupine favored tenderness. Although the EGS did not present significant differences between treatments, it tended to behave in a positive quadratic way (P=0.0681), with the 30% treatment presenting less dorsal fat thickness. From this experiment, it can be deduced that lupine grain is presented as a great alternative to replace energy sources, in this case sorghum grain, presenting similar productive performance without affecting carcass and meat characteristics.