Dairy News AUSTRALIA july 2013
22 // management
Trials show efficient cows consume 20% less feed Agricultural Research Station in New Zealand. The trials subsequently continued A seven-year trans-Tasman study through later lactations. DEPI senior scientist Dr Jennie Pryce has found that some calves and cows are genetically more efficient feed convert- said the research would lead to improved ers than others – but farmers might have breeding values available to Australian to wait a few more years before reaping dairy farmers. “Feed efficiency is of great interest the full benefits of the new information. A feed conversion study under- to dairy farmers and one of the main taken in Australia and New Zealand has motivators behind this research is to shown certain calves and cows have spe- understand more about the actual measures of feed intake cific genetic markers which rather than approximates,” identify them as being more Calves that Dr Pryce said. efficient converters of feed. eat 20% less “Dairy farmers will The trials aimed to idenfeed could be able to improve their tify gene markers for what is known as ‘residual feed save farmers selection of the best cows or bulls to convert feed into intake’ (RFI), which is the $200 from profit.” difference between what weaning to Dr Pryce said about 1000 an animal eats and what first calf. calves were part of the trial it is expected to eat for its live weight and level of growth or pro- in each country. The results of the calf trials in New duction. This meant finding animals that eat less but produce the same amount of Zealand showed the most efficient calves ate up to 20% less feed than the milk as other cows. The project ultimately aims to deliver inefficient calves, which could represent new ways to choose dairy bulls, and cows a saving to farmers of up to $200 in that produce more milk for the same taking them though from weaning to amount of feed without compromising when they first calve. The calves were six months old and health and fertility. The trials started seven years ago their feed intake was measured each day with more than 2000 calves at the for 60 days. They were weighed three Department of Energy and Primary times a week. They were fed lucerne cubes for the Industries Rutherglen site and continued by taking selected calves to participate in trial to provide a consistent feed quality. a lactating experiment at the Ellinbank Electronic feed stations were used to in Victoria under the Dairy Futures ensure individual meals were measured CRC program, and also at the Taranaki and ensure data accuracy. Rick Bayne
Cows in the trial were fed these lucerne cubes to provide a consistent feed quality.
The next stage of the trial was to see if the feed conversion efficiencies in calves could be translated into lactating cows and again the results were positive. The difference in lactation was not as pronounced as in calves at about 4%, but the most efficient calves remained the most efficient at lactation. Dr Pryce said 110 of the least and the most efficient heifers were purchased by the DEPI for follow-up trials at Ellinbank
Food security depends on producing more from less The International Food
and Agricultural Organisation sees research like that of the trans-Tasman project into feed efficiency as critical for the future, according to DairyNZ’s chief scientist, Dr Eric Hillerton. “They are looking at the macro picture for food production to feed the supposed 9.1 billion people that the world will have in 2050,” Dr Hillerton said. “We are significantly short of high value foods like meat and milk. They point to the importance of improving the conversion of relatively low value fibre feeds - the stuff we feed our ruminant animals is where a lot of progress can actually be made. So being even more efficient converters of fibres like grass into human foodstuff is a major challenge going forward.” As a by-product of identifying feed efficient cows, the trial is also helping to reduce methane gas emissions. The research has found that if more efficient cows eat less, and pro-
DairyNZ senior scientist Kevin Macdonald.
duce the same amount of milk, they will have a lower methane production per kg of milk solids produced. Senior scientist with DairyNZ, Kevin Macdonald said that given the variation in the feed conversion efficiency of the calves in the discovery phase of the project, reduction in emissions of up to 5% should be
possible by selection for improved efficiency. Part of the objective of the trial is to establish the relationship between feed conversion efficiency and methane emissions in lactating dairy cows, and to quantify the extent of emissions in low and high feed conversion efficiency animals.
where they were fed Australian-made feed intake data which, at the detail we lucerne and pasture cubes. The results require, is too expensive for commercial were very similar to those from the dairy farms to record.” The results from the trials using earlier lactating cow trial with the cows identified by the RFI markers as being Holstein Friesian cows were similar in most efficient generally remaining most both Australia and New Zealand. Dr Pryce said the research had the efficient. The validation phase of the trials has potential for huge savings for the dairy industry and farmers. recently finished and Dr “We expect it could Pryce said it was hoped to “We need improve the value of the have provisional breeding to ensure dairy industry by about values available within health and $300 million by selecting the next 18 months for for feed conversion farmers to start using the fertility is not RFI as a tool to predict compromised efficiency and other traits using genetics and feed efficiency, including and using biomarkers.” in bulls. genetic “At this stage it is not as DairyNZ’s chief reliable as other breeding markers for scientist, Dr Eric Hillerton values. Currently, the high feed said organisations such as genomic prediction has efficiency is the Food and Agricultural a reliability of 10-12%, cost effective Organisation which are which is a lot lower than looking at ways to feed the milk production traits for farmers.” world’s rapidly increasing (about 60%). While it – Dr Jennie Pryce population see this sort of is still a useful tool, we science as critical for the would like to increase that reliability future. and recommend that it not be used as “They are looking at the macro picture the sole selection criterion.” for food production to feed the supposed Dr Pryce said more recent trials 9.1 billion people that the world will have were determining if the cows maintain in 2050,” Dr Hillerton said. efficiency in lactation and found that “We are significantly short of high they did. value foods like meat and milk. They point “We have to look at the consequences to the importance of improving the conof selecting for feed efficiency. For version of relatively low value fibre feeds example, there were differences in 6 - the stuff we feed our ruminant animals week in calf rate between the extremes is where a lot of progress can actually be and not the way we wanted – the more made. So being even more efficient confeed efficient cows had a poorer six-week verters of fibres like grass into human in-calf rate. We need to ensure health and foodstuff is a major challenge going forfertility is not compromised and using ward,” he said. genetic markers for high feed efficiency The research was supported by the is cost effective for farmers. Gardiner Foundation, the Dairy Futures “We are also collaborating with CRC, DEPI (Agribio and Ellinbank), researchers in seven other countries to DairyNZ and the Livestock Improvement include other information, especially Corporation in New Zealand.