Don’t treat dry cows like mushrooms
It’s that time of year again when spring calving herds are gearing up for calving. The dry period really must be looked at as more than just a rest period from milking; proper management and nutrition of the dry cow are critical for maximising dry matter intake, herd health, reproductive efficiency, and milk production in the subsequent lactation.
This period of preparation for the next lactation is a key period in a dairy cow’s cycle. It is remarkable that when I discuss the diet of a dry cow with customers, it is when I refer to it as lactation preparation that many begin to take the strategy much more seriously. Dry cows should not be treated like mushrooms, is one great saying I heard in the past, they shouldn’t be locked in the dark and fed you know what!
The aims of good dry cow management (lactation preparation period) strategy should include:
Adjust and maintain body condition score (BCS). Ideally, dry cows off at the right condition and maintain it right through to calving. Repair the rumen wall: any digestive upsets in the previous lactation can impair rumen function, a correct diet during the dry period can help to repair that.
IIComplete involution of the udder after drying off (regenerate the mammary gland for the next lactation). Correct protein supplementation, particularly as cows approach calving, will improve colostrum yield and quality. Prime the immune system to minimize disease (a targeted mineral strategy with sufficient Vitamin E and selenium will drive the immune system around the calving event.
Ensure good fertility rates by promoting production of quality follicles that will be released during the breeding season. Stimulate appetite after calving: high fibre diets in the dry period will promote intakes post calving. This will aid milk production and reduce body condition loss in early lactation.
Allow for easy calving and a healthy calf: a well implemented dry cow diet will keep cows fit rather than fat resulting in easier calvings, in general.
Minimise pre-calving and post-calving metabolic disorders: grass silage alone may have nutrient and mineral imbalances, causing metabolic disorders around calving and early in the lactation. Maximise milk solids production in the next lactation by maintaining a healthy rumen. A healthy and hardworking rumen in the dry period will ensure a much smoother transition to the lactating diet, indoors or grazing.
Cows should be dried off at BCS of 3.0-3.5 and maintained at this BCS through to calving. Although it has been common practice to feed cows to gain weight during the dry period, this can have negatives. Dry cows only put on fat when fed for condition, and this fat melts off their back after calving leading to metabolic problems, particularly ketosis, and cows losing condition rapidly after calving have lower milk protein and are harder to get back in calf. If cows are thin in late lactation, it is best to try and regain some of that condition while the cow is still milking. Condition score management should be an all yearround job, not just at drying off, when it is often too late. Prior to drying off, cows could be eating 3% of their body weight, which falls rapidly to 2% once in the dry period.
The developing calf requires additional nutrients as the cow moves to complete the final third of pregnancy. This increased demand is modest, but the increased proportion of the cow’s abdominal cavity being occupied by the calf has a major effect on space available for the rumen and thus on intake potential.
Dry cow feeding
Feeding straw, if it is available, with restricted silage, provides good physical fill and helps to control potassium levels in the diet (2018 first cuts in particular almost all seem to be very high in potassium). Straw intakes should be encouraged to reduce the ration energy density of the diet. Remember that silage (68 plus DMD) is too good for dry cows, resulting in excess body condition gains. Precision chop silage also provides very little structure to promote cud chewing, as it is often too short. Provision of a small amount of concentrates during the dry period will help to promote rumen bug populations in preparation for nutrient rich diets in early lactation.
Straw’s important role
Straw promotes good rumen function which helps to promote extra dry matter intakes after calving. Straw encourages active cud chewing, which produces calcium for the cow’s bones to metabolise, which improves her muscle tone.
This calcium metabolised by the cow has a role in preventing milk fever. Calcium should however not be fed in minerals or in the diet of dry cows. Provision of straw in the dry period often helps to dilute possible negative effects
It isn’t good practice not to feed dry cows minerals, when all the science points to virtually all forages having imbalances which can affect cow performance around ”