The effect of a progesterone/estradiol ear implant on the performance of young beef steers
Boyazoglu, P.A.; Palmer, C.; Campbell, M.C.; Mankgeli, M.R.
Journal of the South African Veterinary Association 63(1): 23-26
1992
ISSN/ISBN: 1019-9128 PMID: 1569536 Document Number: 401064
A progesterone/estradiol ear implant was tested over a 84 d feedlot period on 96 young Bonsmara steers which were randomly allocated to implant and control groups. Animals were adapted over 5 d to a complete feed formulated to South African feedlot standards. Health aberrations were observed and feed intake, mass gain and slaughter data were recorded. The implant group elicited a 23.2 kg gain per animal (P less than 0.01). Mean treatment feed intakes varied marginally but the implant group showed a 14.91% feed to gain improvement over controls. Warm carcass dressing percentage showed an overall improvement of 4.96% for both groups. Bloat incidence was calculated at 0.98% over 8,064 cattle feedlot days. Mortality was 2.08% and 12 animals were considered to be chronic bloaters. This may have been due to the high proportion of fine particles in the diet. A composite feed sample revealed that 62.48% consisted of particle lengths of 0.5-4mm. The effect of this on ruminal health is briefly discussed. It is concluded that the progesterone/estradiol implant provided greater mass gain and improved feed to gain ratios for treated steers over a control group.