Ten experiments were carried out to examine some of the effects of lice infestation on heifers grazing on six commercial properties in the high rainfall areas of Victoria. In all experiments, famphur, a pour-on lousicide, effectively controlled lice populations (main species Linognathus vituli). Lice infestation was associated with lower growth rates in only two experiments. Significant correlations between lice infestation and liveweight gain of untreated heifers were found in three of ten experiments, but infestation accounted for only 23-30% of the variation in liveweight gain. The results support other studies conducted in Western Victoria, and the need for routine whole herd treatment against lice is questioned.
A factorial grazing experiment conducted during 1970,1971 and 1972 at the Pastoral Research Station, Hamilton, Victoria, studied two major management factors in beef production. Post weaning liveweight changes of calves and their dams were measured to compare the effects of either an eight or ten month weaning age and differing nutritional regimes applied from 8 to 12 months post calving. The cows stocked at the higher rate (1.7 cow ha -1) post weaning lost less weight or gained more weight during the test period in three out of four occasions than the cows stocked at the lower rate (1.5 cow ha-1). The results from this experiment confirm the finding of Bailey and Bishop 1972 and show that on perennial pastures in southern Australia, calves weaned at ten months old from autumn calving Hereford cows are likely to be heavier at 12 months old than are calves weaned at eight months onto dry pasture. However, weaning calves at eight months onto hay aftermath would be an effective alternative to ten month weaning. This would also reduce the risk of weight loss by the cow due to later weaning.
In two separate experiments, steers that had been fed hay in a feedlot lost weight during their first week at pasture whereas similar animals that grazed pasture throughout at least maintained liveweight. There was no difference in the grazing time per head of animals previously lot fed and those accustomed to grazing but steers previously from feedlots grazed longer per unit of metabolic liveweight. Length of pasture available for grazing following the feedlot phase was important. Differences in liveweight change between steers previously from a feedlot and those from pasture were less when animals grazed a tall rather than a short pasture. The reduction in loss was not significant.
When yearling beef steers were returned to pasture after being fed in a feedlot, they lost more liveweight than similar steers that had remained on pasture. As the continuous period in the feedlot immediately before common grazing increased, the loss of weight increased. Three, six or nine weeks grazing before the final feedlot period, did not affect weight loss when the steers were finally returned to pasture. The use of hay in decreasing amounts at pasture served only to delay the eventual weight loss of the steers from the feedlots. It is postulated that during hand feeding the steers progressively lost the ability to graze efficiently.
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