Making the most of forage in beef diets, and therefore reducing the requirement for home-produced or bought-in concentrates, not only gives protection from market volatility, it also reduces food miles and carbon footprint, through reducing fertiliser per kg of beef produced.
A recent study by Ireland’s Teagasc Agriculture & Food Development Authority monitored feed efficiency of forages of different digestibility (see Table 1).
To investigate the effects of different silage digestibilities in a real-life ration, Kelvin Cave have taken a typical beef finishing diet, using grass silage and other home-grown feeds, as shown in Table 2.
By running this ration through the Feedmaster beef rationing program, it is possible to see the effects of changing the D-value of silage on both DLWG and the cost of that gain. This is shown in Table 3, which indicates growth rates achieved from the best silage (D-value 75) are some seven percent higher than those achieved from the worst silage (D-value 60). However, in practice, the diets shown in the two right hand columns would not be fed as they oversupply energy. This suggests that the cost per kg gain could be further reduced through better balanced diets.
A more realistic scenario may therefore be to reformulate the diets using the same ingredients, in proportions which maintain the same liveweight gain, while using different D-value forages. We have illustrated this in Table 4. This shows around 10% in feed costs being saved by using high over low D-value forage. This is achieved with a ration comprising almost 58% forage and from a total saving of 3.8kg of home-grown concentrates per head per day. The value of this saving is 12.45p per kg DLWG.
In reality, benefits are likely to be greater than this as a higher D-value silage is likely to also have more protein and sugar and so would perform even better in the diet. However, even taking this conservative, theoretical figure, a farmer with 200 head of cattle in a finishing unit would save over £5,080 using 70 D-value silage and over £13,087 per year using a 75 D-value silage, when compared with a 64.5 D-value silage.
Furthermore, there should be no significant additional costs involved in making high D-value silage as its production could be achieved simply by cutting earlier.
Investing in Safesil and, if necessary, making some changes to clamp management to reduce DM loss in fermentation and at feedout, and improve nutritional quality of the silage will likely bring further improvements.
Similar improvements in profitability can also be seen when feeding better quality silage using bought-in energy and protein blends as explained by independent beef nutritionist Lizz Clarke of LC Beef Nutrition on page 26.