First cuts need careful balancing: Trouw Nutrition

Reflecting the growing season, first cut grass silages are lower energy than in 2015 and will need precise balancing when diets are formulated for the coming winter.

Speaking at the Livestock Event (Wednesday 6th July) when he announced the results of the first 850 grass samples analysed by the company, Trouw Nutrition GB Ruminant Specialist Tom Goatman predicts a challenging winter for many dairy farmers but some good first cut forages have been made which will feed well. “With milk prices still under pressure and feed prices likely to be affected by the impact of the referendum result, getting the most from forage will be important for supporting margins. Our results suggest it may prove difficult to increase production from forage, mainly as a consequence of the growing season.”

Mr Goatman explains the analysis results reflect the growing season and in many ways are similar to forages produced in 2014. The mild winter allowed grass to continuing growing in many areas, while the deterioration in weather in the spring slowed growth and delayed turnout, meaning winter growth was carried forward into first cut. Rapid growth in May led to excessive grass covers.”These factors combined to increase the maturity of grass conserved as first cut and this is reflected in the analysis. On average quality is similar to 2015 but there are fewer high quality samples. The average ME level is 10.8MJ/kgDM which is lower than last year, and this year only 12.3% of samples are 11.5ME or higher compared to 14.8% in 2015.”

Crops are generally drier at 31.2%DM compared to 30.0% in 2015. Crude protein is similar to last year at 14.5% while NDF is slightly higher at 50%. Intake potential is similar at 98.5 and higher than 2014 when it was 93.2, suggesting that cows should be keen to eat reasonable quantities. Lactic acid is markedly lower at 46.9g/kg DM compared to 62.6g/kg DM in 2015. “A cow eating 10kgDM of the average silage will be able to produce M+6.6 litres, 0.3 litres/cow/day down on last year, suggesting more supplementary feeds or concentrates may be required to support target production levels. The combination of higher NDF levels and reduced lignification suggest a greater proportion of the total fibre will be available as an energy source which is good news. The higher NDF levels will also help promote good rumen health and generally this year’s first cuts should reduce the acidosis risk due to a higher fibre index and reduced acid load.”

Mr Goatman also emphasises that the combination of drier crops with higher pH and lower lactic acid content may be more prone to reduced clamp stability and increased aerobic spoilage at feedout. “Overall first cuts will need careful balancing if there are to deliver to their potential. As in previous years there are some excellent crops and the crucial thing will be to get feeds analysed to understand exactly what you have in your clamp and then formulate cost-effective rations accordingly. Resampling monthly and fine -tuning the diets to reflect the silage actually being fed will be essential to exploit the potential in the clamp,” Mr Goatman concludes.

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