Utilización de raigrás (Lolium multiflorum CV. Bill Max) en la alimentación de terneros: Efecto de la oferta de forraje sobre el crecimiento y la producción de carne por hectárea

The objective of the work was to evaluate the effect of grazing intensity, regulated through the forage supply (kg dry matter/100 kg live weight) of a ryegrass pasture (Lollium multiflorum cv. Bill Max) on animal growth, winter meat production per unit area, and forage utilization efficiency. The experiment was carried out in the Intensive Meat Production Unit located at the Experimental Station Dr. Mario A. Cassinoni (EEMAC) Faculty of Agronomy, Paysandú, Uruguay. It was carried out between May 20 and September 3, 2022. 48 Hereford calves, born in the spring of 2021, belonging to the EEMAC breeding herd, were used. They began the experiment with an average live weight of 121 ± 31 kg, these being drawn into 12 groups (after stratification by live weight) and then randomly assigned to the different treatments defined by the supply of forage, which were 2. 5;5.0;7.5;10.0; kg DM/100 kg live weight. Each treatment was composed of 3 repetitions made up of 4 calves grazing an independent plot. Rotational grazing was carried out in occupied plots for 7 days, and then returning to them based on the accumulated biomass. During the experimental period, no significant effect of treatment was detected (P>0.05) on availability and pre-grazing height, as well as on chemical composition. The remnant and its height presented a quadratic response (P<0.01), where the 10% forage allocation resulted in the greatest remnant and its height. The use of forage presented a negative quadratic response, with the lowest utilization value being given in the allocation of 10%. The average daily live weight gain increased linearly compared to forage supply (P<0.01) where for every 1% increase in forage allocation, the average daily gain increased 79 g. On the other hand, beef production per hectare presented a quadratic response, maximizing production with an allocation of 8.06%.