Effect of partially replacing silage with straw-barleysoybean meal mixtures on cow-calf performance

Abstract

Charmley, E. and Duynisveld, J. L. 2004. Effect of partially replacing silage with straw-barley-soybean meal mixtures on cow-calf performance. Can. J. Anim. Sci. 84: 237-244. Forty-eight multiparous, medium-framed cows, calving between Jan. 02 and Mar. 05 were used in a 3 × 2 factorial experiment with three totally mixed ration (TMR) formulations and two levels of protein supplementation. The TMRs were formulated to contain 75, 50 or 25% silage (DM basis). The balance of the diet comprised barley, barley straw, soybean meal and urea, such that all TMRs were formulated to be isoenergetic and isonitrogenous. Supplemental protein was supplied as soybean meal at either 0 or 0.44 kg DM d -1 . Diets were fed from Jan. 11 to turnout on May 26. Intake and performance were monitored during this period, and performance at pasture was recorded until weaning on Sep. 03. The only interactions between TMR and protein supplementation were a positive response to protein for DM intake (P < 0.05) at the 50% silage level and for blood urea N (P < 0.05) at the 25% silage level. Reducing the amount of silage in the TMR had no effects on calf performance or milk production, except that milk protein concentration was higher when the TMR contained 50% silage (quadratic effect; P < 0.04) . However as the percentage of silage in the TMR declined, cows lost less body weight (linear effect; P < 0.001) and appeared to improve in condition. The interval between calving and conception increased linearly as the percentage of silage in the TMR declined (P < 0.05). Supplemental protein had no major effects on performance, but limited the loss of body condition during the feeding period (P < 0.03), although this was offset by increased loss of condition on pasture (P < 0.01). There were no effects of protein supplementation on calf performance or reproductive efficiency. It is concluded that silage can be successfully replaced with other ingredients in winter beef rations, provided the nutrient concentration is balanced. Supplemental protein had little effect on any parameters of performance. manière à produire une ration iso-énergétique et iso-azotée. Le supplément de protéines (tourteau de soja) ajouté à la ration correspondait à 0 ou 0,44 kg de matière sèche par jour. Les rations ont été servies du 11 janvier au 26 mai. Durant cette période, les auteurs ont suivi la prise d'aliments et le rendement des animaux; ils ont aussi mesuré leur performance au pâturage, du sevrage au 3 septembre. Les interactions entre la ration et le supplément protéique se résument à une réaction positive de l'ingestion de matière sèche (P < 0,05) aux protéines avec 50 % d'ensilage et pour la concentration de N uréique dans le sang (P < 0,05) avec 25 % d'ensilage. Réduire la quantité d'ensilage dans la ration n'a aucune incidence sur le rendement du veau ni la production laitière, si ce n'est que le lait renferme plus de protéines quand la ration est constituée à 50 % d'ensilage (effet quadratique; P < 0.04). Néanmoins, quand la proportion d'ensilage dans la ration d...

The partial replacement of silage with straw, with or without barley or soybean meal, in rations for winter calving beef cows

“…However, in contrast to energy, beef cows often exhibit a response in milk production and calf performance when diets are supplemented with protein. This is most apparent in low protein diets (de Garcia and Ward 1991;Wiley et al 1991;Dhuyvetter et al 1993), but has also been observed in diets of higher protein concentration, where the protein is highly degradable in the rumen (Rusche et al 1993;Charmley et al 1999;Charmley and Duynisveld 2004).…”