MANAGING THE TRANSITION FROM SILAGE TO GRAZING Dry matter – is grass providing enough dry matter intake to support energy requirement for milk production and getting cows back in calf? Protein – grass is high in rapidly degradable protein; this needs to be utilised by the rumen microbes in order for them to produce microbial protein. Poorly utilised protein can have a negative impact on fertility and limit milk yield. Rapidly fermentable carbohydrates – early season grass is high in sugar (and digestible fibre), this can be an issue for rumen health. A consequence of this can be milk fat depression and reduction in milk value. It is important to understand the nutrient content of grass. Fresh grass analysis throughout the grazing period will provide useful information about the points above. Q. How do we best handle the challenge on fertility associated with turnout? The two biggest issues linked to fertility that are commonly associated with grazing are dry matter and protein. Grass dry matter can be variable across the season and be very dependent on the level of rainfall. Lower dry matter grass can result in low dry matter intakes which reduce energy availability to the cow. Grass protein level will generally peak at the beginning and end of the season, this protein is very rumen degradable. The cow utilises energy to process excess protein and detoxify, this is energy that could be used to get back in calf. Understanding grass dry matter and nutrient content, via fresh grass analysis or grazing bulletins, will allow you to supplement at risk cows (those not pregnant or in first 100 days of lactation) with specific grazing concentrate, Postbiotic feed additive or buffer feed when required. Q. Turnout can be a challenging time to maintain butterfat, how can we minimise the effect? 50% of butterfat production comes from dietary sources and 50% comes from the fermentation of feed (mainly forage) in the rumen. Anything that effects rumen health will potentially reduce butterfat production. Ensure that cows have access to fibre sources with early season grazing and also reduce any high levels of starch and sugar in supplementary feed. Later in the season (summer) try to minimise the risk of heat stress as this may also effect rumen health. April to July will be the key months to monitor milk quality.
MANAGING THE TRANSITION FROM SILAGE TO GRAZING
As well basic nutritional strategies at turnout, such as reducing the protein level of supplementary feed, increasing digestible fibre and minimising rapidly fermentable energy sources. Farmers can also look toward postbiotic feed additive technology. Diamond V XP is a unique postbiotic product which improves rumen and intestinal fibre digestibility. It increases microbial protein synthesis which helps utilise excess protein from the diet. It also helps to stabilise rumen pH reducing the risk of acidosis. All of the actions improve the overall health and production of the cow at grass and a summary of these benefits can be seen in the diagram opposite:
wynnstay.co.uk
12
