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Bull nutrition in winter months
Cattle farmers, and especially stud farmers, will want to ensure that their bull herd maintains condition and health throughout the winter months to ensure optimal body condition and fertility once the mating season starts again in spring and summer.
Feed requirements for bulls will vary depending on their physiological stages, as a weanling will require a different level of nutrition from a mature bull, and their winter feed requirements will be very much dependant on this stage.
Younger bulls will need a sufficient level of protein and energy, as they are still growing. You will need to take into account the amount of feed they require to maintain a good growth rate, as well as to maintain body condition and body heat throughout the colder months.
Older, more mature bulls will need to be monitored to ensure that they do not lose body condition leading up to the mating season in spring and summer. They should have enough of a fat covering to ensure that they are insulated against the lower temperatures, but not so fat that they develop fertility issues as a result of being obese.
Elements to take into account:
- Energy from fat or carbohydrate sources. This would be in the form of oilcakes (fat) or forages and cereals (carbohydrates). It is important to ensure that the level of energy in the diet is increased.
- Protein sources and supplements such as soybean or canola meal. Protein levels in winter should be at a sufficient enough level that rumen microbes are not affected and are able to produce heat from the feed.
- Minerals such as copper, manganese and zinc which are essential trace minerals that greatly influence fertility.
- Vitamins such as Vitamin A may be deficient winter grazing, and may lead to health and reproductive problems if they are not sufficiently supplemented for. Should a bull not receive enough Vitamin A in its diet, its ability for spermatogenesis is impaired, which leads to a reduced fertility.
- Water should be available to the bulls at all times, it should be clean, not contaminated, and at a temperature that is suitable for drinking. If a bull does not drink sufficient amounts of water, it will suppress the amount of feed that it ingests.
During winter, a farmer should aim to maintain or improve the body condition of his bull herd, and utilising the body condition score (BCS) method may be one of the most useful ways to determine this. On a scale of 1 to 5, with 1 being under thin 5 being overfat, you would aim for you bulls to attain a BCS of 3 – 3.5. Allowing bulls to become overfat leads to a reduced semen quality and semen production, as well as fewer cows mated due to a lack of libido and therefore reduced conception rates.
The farmer may need to separate younger and older bulls during winter, as their nutritional requirements will differ, and they may need to be kept on separate feeding regimes or diets. He may also want to separate bulls with different body conditions, such as separating thin bulls from fat ones so that you can identify an improvement or lack thereof in their condition.
Molatek’s Winter Lick Promotion is currently running until 31 March. Benefit from lower pricing, beat inflation, and maintain your herd’s peak physical condition during the winter months by filling out our contact form here. One of our technical advisors will contact you.