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Dairy bulls gain no benefit from protein supplement
12 June 2009
MTT Agrifood Research Finland
In his dissertation MTT Research Scientist Arto Huuskonen studied the growth results of dairy-breed bulls using various feed combinations. The results indicate that protein supplement does not improve the performance of dairy bulls.
The study also discovered that bulls receive a sufficient supply of phosphorus from grass silage and cereals. Supplementary phosphorus in the form of mineral feed as well as supplementary protein result in increased phosphorus load.
In his dissertation Huuskonen claims that there may be a need to update the current feeding recommendations for growing bulls, and that the current Finnish protein evaluation system may not be optimal for growing bulls older than six months.
Economy among aspects studied
The topic was charted using four experiments. The first experiment involved feeding the bulls three different concentrate proportions; half of the animals were also fed rapeseed meal in addition to a barley-based concentrate. According to Huuskonen the concentrate proportions used in total mixed ration feeding may be quite high, up to 70 percent of dry matter. The optimal economy of feeding is determined by the price of concentrate feed in relation to roughage.
In the second experiment part of the cereal-based feed was replaced with barley fibre, which is an industry by-product. The results show that it is possible to replace a maximum of 50% of a growing bull’s concentrate feed dosage with barley fibre; the economical level is determined by the prices of concentrate feeds.
In an experiment on bull performance involving the impact of three different protein supplements (rapeseed meal, wet distillers’ solubles and a mixture of barley protein and wet distillers’ solubles) supplementary protein did not result in significant responses.
Oats suitable as feed
Huuskonen also compared the impact of various cereals on bull growth, intake and feed utilisation as well as carcass quality. The replacement of barley with oats slightly weakened growth and feed utilisation, but did not have an impact on carcass quality. According to the research scientist there are no obstacles for using oats, providing the price is favourable with respect to other available concentrate feeds. The significance of protein supplement was insubstantial in this experiment as well.
The dissertation of Arto Huuskonen, M.Sc. (Agr. & For.) “Concentrate feeding strategies for growing and finishing dairy bulls offered grass silage-based diets” will be reviewed at the University of Helsinki on 25 June 2009. The opponent is Professor Jørgen Madsen from the University of Copenhagen, Denmark, and the custodian Professor Matti Näsi from the University of Helsinki Deparment of Animal Science.