21 November 1997

ANALYSIS SUPPORTED

BY FEEDING ADVICE

IRISH producers can get more from their silage analysis, because the results are accompanied by concentrate feeding advice based on that silages intake potential.

Rosemary Agnew of the Agricultural Research Institute of Northern Ireland, says that the Hillsborough Feeding Information Service, which incorporates feeding advice with a silage analysis, allows the latest research results to be put into practice.

For suckler cows the advice given is based on the need to restrict intake to avoid unwanted liveweight gain at three stages of pregnancy.

For dairy cows and beef cattle, silage analysis reports show the potential milk yield or liveweight gain for a given silage fed ad lab and at a range of concentrate feed rates based on Hillsborough research. At present this relates to energy supply – advice on protein supplementation is not given.

The feeding advice is based on the intake potential of the individual silage when offered ad-lib. This can be predicted accurately following studies at Hillsborough.

The research measured the degradability of 136 grass silages fed to beef cattle. It found that intake potential is not related to silage fermentation characteristics, but those that influence the rate of passage of material through the animals digestive system.

Rate of passage could be predicted accurately and cheaply using NIRS (near infared reflectance spectroscopy) – a rapid silage analysis technique.

Hillsborough begun its commercial analysis service in Aug 1996 and currently charges £11 a sample.

Predicted intake factor is quoted in the range 45-110 with an average silage at 70. Dry matter, pH, ammonia N, crude protein, and ME are also given, alongside D-value, protein digestibility, FME, ADF and NDF.

"When producers send in the sample, they give details to identify the feeding information required. All reports are in the same format, but the feeding information box is generated from the individuals silage details.

"Producers receiving this information, and who find cattle are not achieving the performance predicted can check silage is not being restricted, for example. It makes producers more aware of what can be obtained when high quality silage is made."

But there are other factors that influence silage intake, such as feed management, breed and age of animals, body condition, environment and type and level of concentrate fed, acknowledges Dr Agnew.

"However, one commercial company monitored how animals performed on farms compared with the Hillsborough Silage Analysis Service advice and found a close relationship."n

Silage analysis results provided with feeding advice makes producers more aware of what can be achieved, says Rosemary Agnew.

ADVICE OFFERED

&#8226 Potential intake prediction.

&#8226 Yield or gain at a range of concentrate levels.

&#8226 Silage restrictions for suckler cows.