The Results are IN and ClipFitter pay-back seems very likely.
Sandy Storrar, Rossie Farm, Auchtermuchty, Fife painstakingly recorded each of his trial group of 200+ individual Lambs (all twins, and split 50:50 rings v clips), their sex, and weight at weaning, along with their respective birth-dates and weaning dates. Daily Live Weight Gains could therefore be calculated and compared – and these are the graphical results. Please be aware that the Data has recently been statistically deconstructed and variation (standard deviation) within groups is so naturally broad, no doubt thanks to parental genes and weather as much as anything, and the sample size (I thought 100 lambs per group was a decent number !) that my simple comparison of averaged data displayed below, is not officially statistically significant. However, despite those theoretical doubts which are affected by sample size v natural weight variations, we feel the principle still applies that if a batch of 100 lambs’ average weight is higher than another batch of 100 lambs, then the £value of the heavier batch is greater to the farmer than the lighter batch. On this trial the difference of total weight at the same weaning age (104days) of 100 lambs was 100+ kilos. Clearly the total weight of the batch would have been more at 150 days but possibly not in a straight line !
We went on to extrapolate DLWG, rightly or wrongly as a straight line, in order to show the time it would have taken to reach a typical market weight of 45 kgs. The results showed that Males would reach target weight 6.3 Days and Females 4.7 Days Faster if left until 5 or 6 weeks of age and castrated and tailed with ClipFitter, instead of ringing at birth. The surprise was that Females benefited from later-legal clip-fitting too. Males might be expected to benefit, hanging onto their testosterone for several weeks, but tail docking a birth must produce more of a ‘check’ that you might have imagined ? As mentioned already, in reality DLWG is probably not linear, and often slows down with age. Whether clips slow it down less than ringing later as is so often the case on hill farms, is not known and is unlikely to ever be known given the problem with admitting to doing that comparison publicly !
Another way of describing (below) the ClipFitter pay-back is by calculating the weight the lamb would reach after a certain number of days on farm. In 150 Days Male Lambs castrated legally later with ClipFitter, would be 2 kgs heavier than their counterparts who had been rung at birth. Even the Females were 1.3 kgs heavier than their sisters who had been tailed at birth and assuming possibly naively that lambs continue to gain weight at the same rate throughout the 150 days !
Hopefully, now you can believe that, the ££ live weight value advantage or the number of days saved in reaching market weight with later legally clipped lambs is worth the 40p clip cost?
