Abstract
Ninety-six calf-fed Holstein steer (127 kg) were used to evaluate the influence of supplemental dietary calcium (Ca) on growth-performance, and dietary net energy (NE) utilization during the initial 112-d of receiving period. Treatments consisted of steam flake corn-based growing-finishing diets supplemented with limestone to achieve 0.60%, 0.70%, 0.80%, or 0.90% dietary Ca (DM basis). Morbidity was low (6.3%) and it was not affected (P > 0.87) by dietary treatments. During the initial 84-d period (181 kg average BW), increasing dietary Ca did not influence (P > 0.10) DMI, ADG, gain efficiency or observed/expected DMI. Observed DMI was 19% greater than expected based on diet formulation and growth. Estimated metabolizable protein and methionine supply during the initial 84-d period averaged 92% and 79% of the required, respectively. The apparent decrease in efficiency of energy utilization in the present study is in close agreement with previous studies involving calf-fed Holstein steers in the early growing phase fed conventional growing-finishing diet that is otherwise deficient in metabolizable amino acids. Thus, it is considered that the anticipated growth-performance responses to dietary Ca treatments may have been masked by expected inefficiencies due to metabolizable amino acid deficiency. During the final 28-d period (256 kg of average BW), increasing supplemental Ca reduced feed intake (linear effect, P = 0.04) and enhanced gain efficiency (linear effect, P = 0.03). During this period, predicted ([1] Level 1) metabolizable protein and methionine supply were 110% and 94% of the required, respectively. Nevertheless, improvements in gain efficiency during the final 28-d period with increasing levels of supplemental Ca were not sufficient to influence (P > 0.10) overall 112-d growth-performance. It is concluded dietary Ca requirements of calf-fed Holstein steers during the initial 112-d feeding period appear to be secondary to deficiencies of conventional steam-flaked corn-based diets in meeting metabolizable amino acid requirements. However, when those requirements are met during the early growing phase, gain efficiency responses are optimized at approximately 0.90% dietary Ca.
Highlights
The effect of supplemental Ca on feedlot growth-performance of yearling cattle has been inconsistent
The apparent decrease in efficiency of energy utilization in the present study is in close agreement with previous studies involving calf-fed Holstein steers in the early growing phase fed conventional growing-finishing diet that is otherwise deficient in metabolizable amino acids
It is considered that the anticipated growth-performance responses to dietary Ca treatments may have been masked by expected inefficiencies due to metabolizable amino acid deficiency
Summary
The effect of supplemental Ca on feedlot growth-performance of yearling cattle has been inconsistent. Based on factorially estimated Ca requirements for maintenance and gain [1], the average Ca requirement for the 310 to 340-d feedlot period in Holstein steers fed a steam flaked corn-based diet is 0.57% of diet DM Due to their comparatively high potential for growth, the factorially derived average Ca requirement during the initial growing phase (initial 112 d on feed) is much greater (≈0.90% of diet DM). Gain efficiency (ADG/DMI) of calf-fed Holstein steers during this initial 112-d period is typically less than 87.5% [7] [8] of expected based on diet energy density and DMI. The objective of the present study is to evaluate the influence of dietary calcium level on growth-performance of calf-fed Holstein steers fed a conventional steam flaked corn-based diet during the initial 112 d on feed
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
