October 15, 2019

AVOIDING THE POST-WEANING SLUMP

So, you’ve made it through the first 60 days or so of raising these calves and it’s time to move them out of their hutch or individual pen and into a group pen. The hard part should be done, right? What could possibly go wrong? Transitioning calves is an extremely stressful time and may cause some challenges with calf growth and performance. Producers spend a lot of their resources ensuring they have a solid calf rearing program, so it’s important to maintain that progress in the transition pens. The key to limiting this post-weaning slump is to minimize stress.

First off, producers need to wean calves off their milk diet according to the farm’s feeding program. A good rule of thumb is to wean healthy, aggressive calves off milk when they are eating a minimum of 2 to 3 pounds of starter for at least three consecutive days. Calves should remain on the same starter grain mix for at least 7 days post-weaning before introducing a lower crude protein grower mix. For optimal performance, calves should remain on a 20-22% crude protein starter grain until 10 to 12 weeks of age and then transition to an 18% crude protein grower mix. Hay should not be introduced until the calf is around three months of age and calves have adjusted to their grower mix. Research has shown that the rate of rumen development is related to production of VFA from readily fermentable carbohydrates, which are present in calf starters, but are low in hay and forages. Continue to offer free choice water to drive grain intakes, support rumen development, and keep calves hydrated. The overall goal is to keep calves growing and developing a functional rumen. During this phase, it is important to maximize papillae development in the expanding rumen to help a calf effectively absorb nutrients from their diet. To meet a herd’s specific goals, this is a conversation to have with a calf and heifer specialist who can tailor a feeding program accordingly.

Regardless of the type of housing prior to weaning, it is still important to give these calves plenty of time to adjust to their new diet before changing up their surroundings. Find an appropriate time to make the move at least one week after weaning. Try to keep groups small and evenly grouped especially in the first transition pen. This will ease the stress of group housing if calves are not already accustomed to it and decrease competition at the feed bunk, waters and resting space. Groups can continue to grow as heifers become acclimated to their new environment.

Whenever periods of stress occur, a calf’s immune system becomes compromised. If calves are not group housed prior to weaning, they now become exposed to higher loads of pathogens—similar to taking children to daycare or school. Avoiding vaccination, dehorning and castration during this time is also critical. It is important to have an appropriate amount of coccidiostat present in the starter and grower to prevent the chance of coccidiosis. Finally, weather extremes may also be detrimental to the animal’s health by changing energy requirements and intakes resulting in more of a suppressed immune system. In cold weather stress, extra grain should be offered to increase energy levels to keep calves growing and gaining.

The transition phase continues to be one of the most challenging times for calves and producers alike. By minimizing the amount of changes and stressors, producers can evade a post-weaning slump. Still finding challenges in your transition pens? Contact your local Ag Partners Calf & Heifer Specialist to review on-farm protocols.

by Hailey Schultz

Hailey.Schultz@agpartners.net

 

Supporting Sources:
https://www.aphis.usda.gov/animal_health/nahms/dairy/downloads/bamn/BAMN17_GuideFeeding.pdf
https://extension.psu.edu/early-weaning-strategies