Successfully managing the transition period is vital for dairy cow productivity. Ensuring a smooth transition can mean the difference between a highly productive cow and one who struggles to perform for the remainder of her lactation.
One of the challenges associated with transition is the dichotomy between the sudden demand for nutrients to support milk production and a dramatic decrease in dry matter intake. These combined factors mean that cows enter lactation in negative energy balance, expending two to three times more energy producing milk than they are consuming in feed. This results in a lot of attention focused on managing intake and energy content of the diet during the transition period. However, cows also experience negative protein balance during transition, which is often overlooked.
So what is one step dairy producers can take for smoother transitions? Recent work from Cornell University highlights the need for additional focus on protein requirements during transition and sheds light on the “optimal” metabolizable protein (MP) for transition cows.
The research
The trial was designed to evaluate the performance implications of increasing MP supply around transition. To do this, the researchers used combinations of low and high MP pre-fresh and post-fresh diets. On average, the low and high pre-fresh diets delivered ~1,200 and 1,600 g of MP respectively, and the low and high post-fresh diets delivered ~2,000 and 2,700 g of MP respectively. These low MP treatments are in line with more traditional MP targets in transition cows. These diets were fed to four different groups of cows that received:
- High MP both pre- and post-fresh
- Low MP both pre- and post-fresh
- High MP pre-fresh and Low MP post-fresh
- Low MP pre-fresh and High MP post-fresh
The MP increase in the high diets was accomplished through inclusion of both heat-treated soybean meal and animal-rendered protein blends.
The pre-fresh diets were fed for 28 days pre-calving, and the post-fresh diets were fed for 21 days after calving. All cows were then fed an intermediate MP diet and data was collected for an additional 20 days to evaluate the persistency of responses.
The results
The trial highlighted clear benefits for increasing MP. Trial results showed:
- Higher postpartum MP led to increased milk, fat and protein yields
- Energy-corrected milk (ECM) production averaged 13.6 lbs/day more during the trial period
- ECM production benefits persisted after supplementation, averaging 11.2 lbs/day more
- Cows fed high MP pre- and post-calving were numerically the highest performing group
The takeaways
From these results, we can conclude that increasing postpartum MP shows clear production benefits, and additionally, these benefits persist beyond the period of supplementation. Benefits of increased pre-partum MP are a little less clear, with limited benefits seen if cows are not also supplemented post-fresh, however, the group supplemented both pre/post were the highest performing of the group. So, practically, how do we go about implementing these strategies on farm? Because the response to increased MP was persistent, implementing this strategy in dedicated post-fresh pens has clear benefits for maximizing peak milk production. The reduced intakes and negative energy balance previously discussed surrounding transition mean that space in the ration is at a premium for trying to implement these MP increases. Most heat-treated soybean meal products contribute around 160 g of MP per lb., compared to greater than 300 g of MP per lb. for high-quality animal-rendered protein blends. This means you can more efficiently supply the 400 to 700 g of MP they targeted in this study using animal-rendered protein blends – like Excelene™ custom amino acid blends from Papillon Agricultural Company – without further compromising energy density of the diet. Speak with your nutritionist and see if a protein blend might be the missing ingredient for your transitioning cows.Click here to view the original article on Farm Journal.
