Productivity index incorporates calf bodyweight at 6, 9 or 12 months and the body weight equivalent of milk produced. As used by Trail and Gregory (1981), measures of reproductive performance, cow and calf viability, milk yield, growth and cow weight are combined to derive the cow productivity index (kg) per cow per year or per 100 kg liveweight of cow of breeding age maintained annually. It is computed as: (cow viability (%) x calving percentage x calf viability (%) x calf weight at 6, 9 or 12 months or at weaning (kg)) + (cow viability (%) x calving percentage x lactation milked-out yield (kg))/9 (Mukasa-Mugerwa, 1989).
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Per Year Per Animal; Per Year Per Metabolic Weight; Per Year Per 100 kg Cow …
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