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Responses to various protein and energy supplements by steers fed low-quality tropical hay. 2. Effect of stage of maturity of steers

McLennan, S. R. and Campbell, J. M. and Pham, C. H. and Chandra, K. A. and Quigley, S. P. and Poppi, D. P. (2016) Responses to various protein and energy supplements by steers fed low-quality tropical hay. 2. Effect of stage of maturity of steers. Animal Production Science . ISSN 1836-0939

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Article Link(s): http://dx.doi.org/10.1071/AN15660

Abstract

Dose response curves to various supplements were established in two pen-feeding experiments (Exp1 and Exp2) with Bos indicus crossbred steers of two age groups (Young, 10–12 months; Old, 33–36 months) fed low-quality tropical grass hays ad libitum. Diets included supplements based on (Exp1) cottonseed meal (CSM; intake (as fed) 0–10 g/kg liveweight (W).day) and a barley mix (Bar; 0–20 g/kg W.day) and (Exp2) a molasses mix (MUP) and a Bar mix, both fed at 0–20 g/kg W.day. Urea was provided with the Bar mixes and urea/copra meal with the MUP mix. Growth rates of Young steers increased linearly with Bar and MUP supplements but asymptotically with CSM whereas those of Old steers increased asymptotically with all supplement types. With supplement intake expressed on a liveweight basis (g/kg W.day), responses were greater for both steer age groups with CSM compared with Bar (Young, P < 0.001; Old, P < 0.01) and Bar compared with MUP treatments (Young, P < 0.01; Old, P < 0.05). Furthermore, Old steers outperformed their Young counterparts with both CSM (P < 0.05) and Bar (P < 0.001) supplements fed in Exp1 and with Bar and MUP supplements (P < 0.01) fed in Exp2. When supplement intake was expressed in absolute terms (kg/day), growth responses were not different between age groups for different supplements except that Old steers had a higher daily W gain on Bar than their Young counterparts (P < 0.05). Intake of hay (W-corrected) was higher for Young compared with Old steers without supplement but was variably reduced for both steer groups with increasing supplement intake. The results of these experiments have implications for supplement formulation for steers at different stages of maturity grazing low-quality forages.

Item Type:Article
Business groups:Animal Science
Subjects:Animal culture > Cattle
Animal culture > Feeds and feeding. Animal nutrition
Deposited On:01 Jun 2016 07:04
Last Modified:01 Jun 2016 07:04

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