As we approach mid-September it is great to be able to report that we are in a very good grass growing situation in relation to the amount of grass available on most farms across the country. The target should be to extend the rotation length to approximately 35 days and build sufficient grass covers to maximise the inclusion of grazed grass in the diets of dairy herds. Therefore it is of paramount importance to estimate and monitor grass covers on a weekly basis to make informed decisions.
Unfortunately, in the last few days rainfall has been widespread across the country of which is making grazing conditions very difficult and grazing intensity is not at optimum. Ideally I would be advising to graze paddocks down to 4-4.5cm to allow high quality regrowth in the last grazing prior to closing off which would be in mid-October. However a grazing residual of 4-4.5cm is not permissible at the moment, but we must try to endeavour and graze as tight as possible without damaging paddocks.
Hopefully the weather will improve and grazing conditions will allow a better utilisation of grazed grass to promote better milk solids across the country. Where there is a shortfall in total dry matter intake, supplementation will be required to avoid body condition loss and to maintain milk yield. Energy and protein will need to be balanced correctly to offset the degree of mobilisation. It is important to have cows at an optimum body condition score at 2.75 prior to drying-off, so dairy cows will not have to gain much condition over the dry period – optimum dry period length would be 60 days.
It is important to mention at this stage of the year the overall grass quality will be in decline, principally the dry matter and protein content. Thereby it is important to negotiate these changes in forage quality with a buffer feed or through in parlour feeding. My advise is to target an overall protein content of 14-15% in the diet and can be corrected through in parlour feeding of a high energy 18% dairy cube or coarse ration available from Connolly’s RED MILLS. Key to buffer feeding will be to balance the diet correctly to avoid any substitution effect in terms of elevated grazing residuals.
Depending on forage quality and days in milk a supplementation of approximately 2-4 kg per day will achieve a desired outcome to maximise milk solids within the dairy herd. It is also worthwhile mentioning at this time of the year grass tetany cases are more prominent with the luxury uptake of nitrogen from the sward, thereby locking up the availability of Magnesium. The dairy cow has a low capability of storing magnesium and requires approximately 56 grams of pure Magnesium to help prevent grass tetany on daily basis.
For further advice on getting the most from autumn grazing conditions, please do not hesitate to contact any member of the Connolly’s RED MILLS ruminant team.