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Nutrition Focus
Dry Cow Groups – As Easy as 1...2...
 Glenn Smith, Senior Nutritionist, Trouw Nutrition
Two group dry cow management programs (far-off and close-up 21 days pre-partum) have been used for many years with apparent success, but the practice of increasing starch for energy density in close-up group rations has not always solved transition cow problems. In recent years, several producers have been successfully feeding a one-group TMR during the entire dry period. Much of this improvement may be due to better facilities and more attention to detail in the management of dry cows. Providing comfortable environments, avoiding overcrowding and detailed care at calving have all contributed to transition period success.
What we feed to far-off dry cows does impact what happens at calving and early lactation. High forage, low energy far-off diets are beneficial in providing rumen fill. There is evidence that suggests a lower energy diet for the complete dry period may better adapt the liver and other tissues to
handle increased fat mobilization in early lactation. Also, the bulkiness of these diets should reduce the risk for displaced abomasums.
Utilization of Straw
Adding chopped straw to a dry cow diet will decrease ration energy while allowing cows to eat all they want. With corn or grass silage in the diet, it may take up to 30% straw to get the energy content to the desired lower level. Straw is preferred to other lower energy forages (e.g. higher fibre grass hay or silage) as the hollow stems, slow rate of digestion and passage rate can allow some straw to remain in the rumen for weeks after feeding it. Consequently, the rumen of the fresh cow is automatically transitioned when the cows begin eating the lactating TMR and the remaining straw in the rumen is slowly diluted. (A recently published study by UBC found no benefits to adding chopped straw to an early lactation TMR.)
While the consistency of straw is preferred, grass hay may be a substitute. However,
grasses are normally higher in potassium and may be more inconsistent in terms of nutrients and palatability than straw. If grass silage is substituted, ensure that it is well fermented, free of mold and below 1.8 – 2.0% potassium. Feed bunks need to be cleaned regularly if using grass silage as it tends to heat and grow mold over time.
Chopping the straw prior to mixing is critical to prevent sorting. The straw should be chopped to a uniform length of 5 to 7 cm to enable the straw particle size to fit cross-wise inside a cow’s mouth. It takes 7 – 10 days to adapt to higher forage diets. Introduce a high straw ration to the far-off group prior to changing the close-up diet. Consider adding water in diets above 60% dry matter.
Concentrate Formulation
If moving to one dry cow group, lower energy total mixed ration (TMR) concentrate formulation is critical. On higher forage, lower starch diets, the microbial protein yield is lower when compared to higher starch diets because of less fermentable
carbohydrate. Therefore, high quality rumen undegradable sources of protein may be required. When feeding first lactation animals, metabolizable protein should be increased to compensate for growth requirements and account for lower intake compared to larger, mature cows. The concentrate must be formulated to supplement vitamins and minerals at dry cow requirements throughout the whole dry period and would typically be a high protein, low inclusion
Cow Comfort and
Although ration formulation and diet regimes are crucial, cow comfort and environment are also key factors affecting transition performance. Moving cows into maternity pens between 3 and 9 days before calving has been associated with more health problems and more cows culled prior to 60 days in milk than cows that are moved to pens immediately prior to calving or more than 10 days pre-partum. Also, excess cow density resulting in overcrowding will lead to transition problems. Close-up pen density should not exceed 80 percent.
So which strategy is best?
Both two group and one group dry cow systems work well; is one best? That depends on a number of factors including facilities, body condition, simplicity i.e. ease of mixing two rations vs one ration, length of dry period and whether a separate fresh cow transition ration is fed after calving. If facilities allow for two groups, a one-group dry cow ration for heifers and one for mature cows may be considered to alleviate social stress between heifers and mature animals. When using the Far-off/ Close-upapproach,feedadditivestargeting the transition cow may be provided for a shorter period of time.
Management changes in housing, group size and movement, water availability and post-fresh monitoring may be as important in transition success as the diet itself. Consider your operation carefully to determine the best dry cow strategy for your dairy.
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