Lorraine Illston – at her happiest out on the farm.
To calculate the feed intake, it’s simply a case of multiplying the number of each class of stock by their average liveweight by the percent of liveweight that they consume depending on their status.
This percentage has been calculated for ruminants at 2% of their liveweight for maintenance level to 4% of their liveweight for maximum intake – usually ewes at peak lactation or fast-growing lambs or beef cattle. It can be fine-tuned with experience, and by factoring in variables such as shearing, weaning, flushing etc, but an average of 3% bodyweight gives a pretty good estimate.
By putting in the known factors – pasture growth in kg/DM/ha/day, daily feed demand in kg/DM/ha and pasture cover, Mark is able to foresee when he’s likely to move into deficit. This formula can be worked out daily, weekly or monthly depending on the time of year.
Mark works out his target covers from lambing time backwards, and it’s a case of juggling numbers to arrive at a “fair play” scenario. His main budget plans are done in October for weaning time, February for tupping and March/April for wintering. He adds that an understanding of soil moisture evaporation levels is beneficial when hot or cold windy days have stunted growth well below what is “average”.
Another word of caution is that hoggets will tend to eat all 4% of their bodyweight if they are offered quality feed ahead of the ewes. This can create an unexpected shortage of feed available at lambing.
