The cost of the summer drought on winter feeding will soon start to be felt, and estimates put it at about £8,000-16,000 for a 100-cow herd if yields are to be maintained with concentrates.
Trouw Nutrition’s latest analysis of this year’s grass silage is showing a better than expected quality but a predictable and worrying deficit on quantity (See table below).
Estimates put the shortfall at about 10 per cent which means producers can feed as usual and hope for an early spring, or measure the clamp and feed less to make sure it stretches the full 200-day winter.
According to Trouw Nutrition, 10kg dry matter (DM) silage per day should produce of the order of M+9 litres, but restricted silage availability will reduce the figure dramatically.
Cutting back to 8kg DM silage will mean only M+5 litres from forage, which would then require 1.85kg/cow concentrates at a cost of 41.5p/cow/day to make up the shortfall.
And for those having to eke out their silage at 6kg DM it means the extra concentrate needed to maintain yield is 3.73kg, costing 84p/cow/day.
In response to the limit on silage stocks, many compounders have introduced forage extenders in an attempt to complement the silage analysis without incurring the full cost of concentrates.
These typically consist of soya hulls, straw and elements such as wheat feed and oat feed and can also include urea and molasses.
Dr Liz Homer, Trouw Nutrition’s ruminant technical development manager, said: “Forage extenders have a place in providing rumen fill and fibre to maintain rumen function but are a low energy feed.
“Comparing a diet with 10kg DM from silage and one with 6kgDM silage and 4kg DM of a typical extender, you will have lost a litre which nutritionists will have to recover elsewhere in the diet.”
But using extenders also means you reduce the amount of rapidly fermented carbohydrate in the diet, which does give the opportunity to incorporate more cereals without overdoing the acid loading.
“However, the glucogenic energy will be lower on high proportions of extender and this means cows may take longer to get back into a positive energy balance which could impact on fertility,” she added.
“The proportion of extender to silage will affect what other feeds are used to supplement the diet. While grass silage diets will need more bypass energy and protein, those on a high proportion of extender may need cereals for RFC and maize to boost their glucogenic energy.”