Modelling: Effect of feeding plantain pasture to three different breeds of calf/heifer on weight gain and nitrogen leaching in Canterbury

Abstract

Four levels of plantain (0%, 25%, 50% and 75% on DM basis) inclusion rate to ryegrass-clover pasture and three target heifer mature live weights, 444 kg (representing Jersey), 529 kg (Friesian), and 492 kg (cross bred Jersey × Friesian) were tested in this modelling exercise for a 30 ha farm and 24-month analysis. The annual average growth rates were 30 kg DM/ha/day and 23 kg DM/ha/day for plantain and perennial ryegrass-white clover, respectively. Feeding plantain increased animal live weight gain, but on a whole farm level, total live weight gain was similar between the three target weight treatments. Stocking rate was identified as a major driver of nitrogen leaching in this study, which resulted in a decreased nitrogen leaching with increased target live weight groups. Increased annual nitrogen leaching value was found from feeding plantain to animals, which contrasts to previous speculation from animal studies.