PROVIDING adequate feed and nuitrition for cattle is a primary concern for dairy farmers at this time of year. However, after a difficult winter weather-wise, grazing conditions are far from ideal and careful management is required.
The main concerns for dairy farmers are;
• To ensure energy and protein intakes are sufficient to allow the full milk potential to be realised.
• To avoid excessive weight loss in animals between calving and the breeding season.
• To manage the first rotation so that it does not end before the early April for drier soils and mid April on heavier soils.
• To try to maximise the amount of grazed grass in the animals' diet. This will reduce costs, improve milk protein and prevent large weight losses.
GRASS IS VITAL
The amount of grazed grass in the diet of cows at the moment is largely determined by soil type. Heavier soils are more difficult to graze, with some poaching of paddocks last autumn and reduced growth rates due to low temperatures. The amount of concentrates fed will be determined by how much grass farmers can get into cows. Where cows are out full time on good free-draining soils, with adequate grass supply, they will consume at this stage up to 13kg of forage dry matter. Research has shown that an economic response can be achieved in this situation by feeding up to 3.5 to 4kg of ration per day. This benefit transfers into the remainder of the lactation and is reflected in higher yields.
OUT BY DAY ONLY
On heavier soils or where grass is scarce, cows are generally out by day and indoors on silage by night. In this situation 3 - 4kg of concentrate is recommended. The meal input may have to be increased where silage quality is very poor and grazing conditions are still very difficult. Some farmers report that cows are eating very little silage at night, which would indicate very good intakes of grasses.
Where grass is very limited or soil conditions very poor, with cows grazing for only short periods daily, grass intakes may be as low as 4kg of dry matter per day. In these situations meal inputs would need to be 5 - 5.5kg. per day with silage.
HIGH PROTEIN IN THE RATION
The protein requirements of the ration will vary depending on the amount of grass in the diet. Cows still on a full silage diet, will need 18% -20% protein in the ration. Where cows are on grass by day and silage by night 16% - 18% crude protein is sufficient. Cows full time on grass will have adequate protein on a 12% - 14% crude protein ration. Ration should also contain magnesium to prevent grass tetany.
On difficult soils, restricted access to pasture can help to achieve higher intakes of grass dry matter without damaging soils. There is ample research evidence and anecdotal evidence from farmers which suggests that cows allowed access to pastures twice per day for three or four hours after milking can achieve dry matter intakes similar to cows on full time grazing.
While feeding of silage with this system did increase dry matter intake, it did not result in improved milk yield and led to lower milk protein by reducing grass dry matter intake.