The Winter Diet in the Last Month of Gestation

Over the last 10 years, management of the dry cow to attain optimal condition has been much improved. This has been mainly facilitated by setting realistic figures on crop utilisation (90% for FB and 80% for Kale in good conditions) and ME requirements for condition gain (70MJME/kg liveweight gain), maintenance (60MJME) and pregnancy (30-50MJME – 6 to 2 weeks from calving). Also factor in the increased requirements due to wet, wind chill and mud which can add an additional 10-30MJME/day.

Ensure that cows are not getting over-fat or are at risk of not achieving target. A BCS (from your vet) at the start of July can tell you whether intakes need to be increased or decreased.

The winter diet for a pregnant cow, through until about the last 3 weeks of pregnancy, requires about 11% crude protein in the diet (or 1.2-1.4kg of crude protein). As well as cow’s normal base protein requirements, she has the demands of a rapidly growing calf, the development of new udder tissue and production of colostrum antibodies. Cows under protein stress for significant periods of time will break down their own tissues to meet foetal demands, but the end result may be muscle loss (calving difficulty), poor udder development, poor colostrum quality and poor cow immunity (placing her at greater risk of mastitis or metritis).

Optimal crude protein requirements increase to >16% in the last 3 weeks before calving. Typically Fodder beet bulbs have crude protein levels less than 10%, whereas the leaf is in the 15-20% range. If the crop you are feeding is losing leaf yield in July, ensure that cows are receiving an additional supplement that has higher protein content.