Feed energy standard - Cows eat more after calving
Cows receiving a low energy feed ration during the dry period generally perform better than cows receiving excessively high energy feed. Dry cows should always be fed according to appetite and preferably with a Total Mix Ration (TMR).
However, it is also standard to feed cows restrictively during the dry period with the same advantageous effect, but this requires feeding twice a day and preventing one cow from taking another cow's ration from the feeder. This principle can be applied if good quality straw cannot be obtained or if the ration cannot be comminuted.
Cows receiving a low energy level feed during the dry period have a higher feed intake (+ 10-15%) after calving. There is less mobilization of body fat so less risk of developing subclinical and clinical ketosis.
High energy feed (over 10-15% above the energy standard) in the dry period means a lower feed intake after calving, higher mobilization of body fat in early lactation and thus a higher load on the metabolism and increased risk of ketosis and fatty liver.
12-13 % crude protein is sufficient throughout the dry period
AAT maintenance requirements are very low, and although AAT (amino acids absorbed in the intestine) for foetal growth doubles during the dry period, the overall need is still low. This means that if PBV (protein balance in the rumen) is above 0, the AAT supply will most often be sufficient to meet requirements.
Protein supply during the dry period and the significance for subsequent milk and milk protein performance during lactation is uncertain. Different experiments have shown different results.
This may be due to the difficulty in distinguishing between effects, which may be either direct in the form of extra amino acids for the metabolism or indirect involving higher digestibility of poor feed thus increasing the protein level.
Requirements are low and can be met by a level of approximately 10% crude protein in the first half of the dry period. Dropping below 12% crude protein is not recommended for dry cows because they need to utilize the energy in the feed ration.
During the last part of the dry period, the level should be between 12-13% crude protein, so that the cow becomes accustomed to the lactation feed and the increased needs of the foetus. So, if the same ration is used throughout the dry period, the protein level should be between 12-13%.
