Dietary Phosphorus Requirement of Holstein Steers During Early Growing Period

Abstract

López, J.R., Montaño Gómez, M.F., Jorquera, A.P., Chavira, J.S. and Zinn, R.A. 2007. Dietary phosphorus requirement of Holstein steers during early growing period. J. Appl. Anim. Res., 31: 113–115.

Ninety-six Holstein steer calves (120.7±5.3 kg) were used to evaluate the influence of dietary phosphorus level (0.27, 0.31, 0.35 and 0.39%, DMB) on growth-performance during the initial 105 d on feed. Dicalcium phosphate was the source of supplemental phosphorus. All diets were formulated to contain 0.85% calcium (DMB). Dietary phosphorus level did not affect (P>.10) DMI or body size measurements. However, increasing dietary phosphorus level increased ADG (linear component, P<.05), gain efficiency (quadratic component, P<.05) and dietary NE (quadratic component, P<.05). It is concluded that during the initial growing period ADG, gain efficiency and dietary NE are optimal at a dietary phosphorus level of 0.35%, 15% lower than current NRC recommendations.

Keywords:

• Requirement
• phosphorus
• Holstein
• growth
• feedlot