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Energy and protein requirements for growth and maintenance of F1 Nellore x Red Angus bulls, steers, and heifers.
J Anim Sci 2007; 85(8):1971-81JA

Abstract

A comparative slaughter trial was conducted with 36 F1 Nellore x Red Angus calves (12 steers, 12 bulls, and 12 heifers), averaging 274 kg of BW, to assess the net requirements of protein and energy for growth and maintenance. Three cattle from each group (i.e., steers, bulls, and heifers) were slaughtered at the beginning of the trial to determine the initial body composition. The remaining calves were randomly assigned to 1 of 3 treatments: maintenance (diet containing 70% of DM as corn silage fed at 1.2% of BW daily) or concentrate at 0.75 or 1.5% of BW daily with corn silage available for ad libitum consumption. The diets were isonitrogenous (2% N, DM basis). The experimental design provided ranges in ME intake, BW, and ADG for the development of regression equations to predict the maintenance requirements for NE and net protein (MRNE and MRNP, respectively) and the growth requirement for NE and net protein (GRNE and GRNP, respectively). After 84 d of growth, the cattle were slaughtered. The cleaned gastrointestinal tracts, organs, carcasses, heads, hides, tails, feet, blood, and tissues were weighed to measure empty BW (EBW). These parts were ground separately and subsampled for chemical analyses. For each animal within a period, DMI was measured daily and samples of feces were collected to determine diet digestibility. There were no differences in MRNE (P = 0.06) among groups. The combined data indicated a MRNE of 71.2 kcal x kg(-0.75) of EBW x d(-1), with a partial efficiency of use of ME to NE(m) of 0.71. The partial efficiency of use of ME to NE for growth was 0.54 for bulls, 0.47 for steers, and 0.54 for heifers. The GRNE for steers and heifers were similar (P = 0.15) but were 18.7% greater (P = 0.03) for steers and heifers than for bulls. The MRNP did not differ among groups and averaged 2.53 g of CP x kg(-0.75) of EBW x d(-1). Likewise, GRNP was not different among groups. The percentage of retained energy deposited as protein (RE(p)) increased as the content of retained energy in the gain (RE(c), Mcal/kg of empty body gain) decreased. The RE(p) equation of the pooled data was 46.5 x e(-0.2463 x RE(c)). We conclude that the energy requirement of crossbred Bos indicus x Bos taurus for maintenance might be less than that of purebred Bos taurus and that RE(p) is nonlinearly, negatively correlated with RE(c). The GRNE was less for bulls than for steers and heifers. However, we found no differences in MRNE, MRNP, and GRNP for bulls, steers, and heifers of Nellore x Red Angus crossbreds.

Authors+Show Affiliations

Department of Animal Science, Universidade Federal de Viçosa, Viçosa, MG 36571, Brazil.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17504963

Citation

Chizzotti, M L., et al. "Energy and Protein Requirements for Growth and Maintenance of F1 Nellore X Red Angus Bulls, Steers, and Heifers." Journal of Animal Science, vol. 85, no. 8, 2007, pp. 1971-81.
Chizzotti ML, Valadares Filho SC, Tedeschi LO, et al. Energy and protein requirements for growth and maintenance of F1 Nellore x Red Angus bulls, steers, and heifers. J Anim Sci. 2007;85(8):1971-81.
Chizzotti, M. L., Valadares Filho, S. C., Tedeschi, L. O., Chizzotti, F. H., & Carstens, G. E. (2007). Energy and protein requirements for growth and maintenance of F1 Nellore x Red Angus bulls, steers, and heifers. Journal of Animal Science, 85(8), pp. 1971-81.
Chizzotti ML, et al. Energy and Protein Requirements for Growth and Maintenance of F1 Nellore X Red Angus Bulls, Steers, and Heifers. J Anim Sci. 2007;85(8):1971-81. PubMed PMID: 17504963.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Energy and protein requirements for growth and maintenance of F1 Nellore x Red Angus bulls, steers, and heifers. AU - Chizzotti,M L, AU - Valadares Filho,S C, AU - Tedeschi,L O, AU - Chizzotti,F H M, AU - Carstens,G E, Y1 - 2007/05/15/ PY - 2007/5/17/pubmed PY - 2007/10/17/medline PY - 2007/5/17/entrez SP - 1971 EP - 81 JF - Journal of animal science JO - J. Anim. Sci. VL - 85 IS - 8 N2 - A comparative slaughter trial was conducted with 36 F1 Nellore x Red Angus calves (12 steers, 12 bulls, and 12 heifers), averaging 274 kg of BW, to assess the net requirements of protein and energy for growth and maintenance. Three cattle from each group (i.e., steers, bulls, and heifers) were slaughtered at the beginning of the trial to determine the initial body composition. The remaining calves were randomly assigned to 1 of 3 treatments: maintenance (diet containing 70% of DM as corn silage fed at 1.2% of BW daily) or concentrate at 0.75 or 1.5% of BW daily with corn silage available for ad libitum consumption. The diets were isonitrogenous (2% N, DM basis). The experimental design provided ranges in ME intake, BW, and ADG for the development of regression equations to predict the maintenance requirements for NE and net protein (MRNE and MRNP, respectively) and the growth requirement for NE and net protein (GRNE and GRNP, respectively). After 84 d of growth, the cattle were slaughtered. The cleaned gastrointestinal tracts, organs, carcasses, heads, hides, tails, feet, blood, and tissues were weighed to measure empty BW (EBW). These parts were ground separately and subsampled for chemical analyses. For each animal within a period, DMI was measured daily and samples of feces were collected to determine diet digestibility. There were no differences in MRNE (P = 0.06) among groups. The combined data indicated a MRNE of 71.2 kcal x kg(-0.75) of EBW x d(-1), with a partial efficiency of use of ME to NE(m) of 0.71. The partial efficiency of use of ME to NE for growth was 0.54 for bulls, 0.47 for steers, and 0.54 for heifers. The GRNE for steers and heifers were similar (P = 0.15) but were 18.7% greater (P = 0.03) for steers and heifers than for bulls. The MRNP did not differ among groups and averaged 2.53 g of CP x kg(-0.75) of EBW x d(-1). Likewise, GRNP was not different among groups. The percentage of retained energy deposited as protein (RE(p)) increased as the content of retained energy in the gain (RE(c), Mcal/kg of empty body gain) decreased. The RE(p) equation of the pooled data was 46.5 x e(-0.2463 x RE(c)). We conclude that the energy requirement of crossbred Bos indicus x Bos taurus for maintenance might be less than that of purebred Bos taurus and that RE(p) is nonlinearly, negatively correlated with RE(c). The GRNE was less for bulls than for steers and heifers. However, we found no differences in MRNE, MRNP, and GRNP for bulls, steers, and heifers of Nellore x Red Angus crossbreds. SN - 1525-3163 UR - https://www.unboundmedicine.com/medline/citation/17504963/Energy_and_protein_requirements_for_growth_and_maintenance_of_F1_Nellore_x_Red_Angus_bulls_steers_and_heifers_ L2 - https://academic.oup.com/jas/article-lookup/doi/10.2527/jas.2006-632 DB - PRIME DP - Unbound Medicine ER -