Adoption of selection strategies influencing body composition (e.g. RBY and NFI) constrained by industry concerns about impact on breeding herd efficiency, especially in variable nutritional environments
Does selection for improved NFI or RBY% influence breeding herd efficiency* ?
Hypothesis: Selection for reduced NFI and reduced carcass fatness increase breeding herd efficiency in good, but not in poor nutritional environments * Kg of cow and calf liveweight / MJ energy consumed by the breeding herd
Heifer management Nutritional treat’s applied 9 week joining Calving 9 week joining Nutritional treat’s applied Calving Weaning Weaning Vasse Struan 9 week joining 9 week joining Sep Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec Jan Feb June July Aug Sep Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep Oct Nov
Energy Supply & Demand: Early Calvers & Late Calvers
Rainfall (mm) 2006: 577 mm 2007: 810 mm 2008: 671 mm 2009: 679 mm 2010: 464.1mm