Towards a data set to investigate feed efficiency in New Zealand maternal sheep

Residual Feed Intake (RFI) as a measure of feed efficiency has not been reported for New Zealand maternal sheep breeds. This trial reports on a pilot trial that generated RFI data on 37 16-month old maternal composite ewes Records on ten were obtained utilising a prototype automated feeder with the remainder fed in individual pens. The animals were introduced to lucerne pellets over two weeks before daily feed measurements were made over 42 days with animals weighed twice weekly. The RFI model fitted to determine the relationship between the weight and ADG and the intake of the animals had an R2 of 0.76. The observed phenotypic standard deviation of RFI was 187 g of DM/d for RFI which is 7% of the average daily intake. The animals were ranked for RFI, with the 15% most efficient animals (low RFI) consuming on average 0.6kg/day less feed, or 24% than the 15% least efficient animals (high RFI). Additional data, collected for the 10 animals using the prototype automated feeder, included the number and size of feeding events per day which showed consistent variation. The longer term data collection will take place over the next several years will aim to collect data on 800-1000 animals. The animals will be sourced from the Central Progeny Test and will represent NZ maternal sheep breeds which will be measured for a range of other production traits allowing the heritability of the trait and its genetic correlation with other traits to be estimated.