There are many different varieties of turnip available including Barkant, Greenglobe and Whitestar. Every variety has slightly different yield and maturity characteristics with most turnips fed from 60-110 days post planting. Later maturing varieties like Greenglobe are often fed from 80/100-150+ days post planting. Planting a number of varieties with differing maturity dates allows you to plant in late October when the weather is best, yet also to feed over a much longer period in summer. Attention to weed control is needed initially and regular checks for insects are required.
Turnip bulbs contain the bulk of the energy, while the leaf is richer in protein. The leaves also have a high concentration of calcium, so avoid sudden removal of turnips from the cows feed if milk-fever is an issue. The ideal ration is to get a mix of both leaves and bulb.
Overestimation of the dry matter yield from your turnip crop is a common trap to fall into. Weight loss in dairy herds is, unfortunately, all too familiar where turnips are fed and is much more common when turnips are a large portion of the ration and the total ration is inadequate. Be realistic about dry matter yields, a good crop will yield 10-12T DM per hectare and yields of 6-8T DM per hectare (or less) are not uncommon if critical steps in cultivation/pest control/fertilisation have been missed..
Animal Health Issues
Although uncommon, we do see these conditions from time to time:
Photosensitisation: The turnip is subject to heat stress in drought conditions and may predispose cattle to photosensitivity. The signs of turnip toxicity may be likened to the skin sensitivity seen with facial eczema. We can do blood tests which can help indicate if the photosensitivity is more likely to be from turnips or facial eczema.
Choking: turnips can lodge in the oesophagus. The cow will bloat on the left hand side and usually have ingesta discharge form the nostrils.
Acidosis: If large quantities are introduced too quickly, acidosis can be a problem. Ruminal bacteria require 5-7 days to adjust.
Milk tainting: Turnips can taint the milk if fed in large quantities. Milk companies prefer turnips not to be fed prior to afternoon milking.
Prevention of animal health issues
If introduced slowly (no more than 2kg per day for the first week (2-3m2 per cow), then these conditions are usually avoided. It is prudent to feed turnips on a long thin face to stop the animals from trampling or soiling the feed. Hot, moist conditions can also lead to turnip rot and increased wastage. The longer “face” allows equal access to a large group of animals, and holding cows back to allow the whole herd access to the crop simultaneously, will make sure all cows have equal opportunity. Combining turnip feeding with silages/maize silage can combat the weight loss commonly seen when fed solely with grass. Turnips should not make up more than 1/3 of the diet.
If you would like to know more, please contact your local Anexa Vet.
