Dairy producers must constantly evaluate their operations to limit economic losses and secure a profit. This includes considering current feeding management strategies with the goal of providing all cows with the nutrients they need without excess.
Especially with our currently high feed prices, there should be a benefit to feeding multiple lactating rations rather than feeding one ration to all lactating cows. On dairies employing this strategy, I most often see four milking groups:
- High mature
- First lactation
Early lactation cows will usually respond profitably to a higher-quality diet balanced for amino acids, with higher levels of fat, and containing proven feed additives. On the flip side, late-lactation cows can easily maintain their milk production on a more basic diet. They need fewer nutrients to support milk production, and a higher percentage of their protein and energy needs can be met from the rumen fermentation. Having multiple feeding groups helps reduce body condition loss in early lactation and body condition gain in late lactation, improving feed efficiency, transition cow health, and reproduction.
The pen move dip
It is not uncommon to hear dairy producers complain about cows dropping in milk output when moved between pens. However, with careful diet balancing and cautious pen moves, production losses can usually be controlled when switching cows from a high- to a low-production pen. Little can be done about negative social impacts aside from limiting overcrowding, moving several cows at a time, and avoiding moves at times of peak eating.
Generally, for lower-production diets, I try to support more milk from protein than average pen milk. For example, if the pen is averaging 70 pounds per cow per day, I still make sure that I have enough protein to support 75 to 80 pounds per cow per day. I also try not to raise forage neutral detergent fiber (NDF) percent dry matter (%DM) too much from the previous diet because I don’t want this change to reduce dry matter intake.
Real pen numbers
Alex Bach, a well-known researcher from Spain, recently published a scientific article in which he reported changes in milk production and income over feed cost (IOFC) associated with 2,142 cow moves between pens. The study took place on three different commercial dairies. Each dairy manager made the individual cow decisions regarding moves between pens. All cows changed from a more expensive, nutrient-dense diet to a cheaper diet.
Individual daily cow milk weights and body weights were recorded for 21 days before and after every pen move. The table shows changes in diet nutrients before and after cow moves as well as predicted versus actual milk yield and IOFC after cow moves.
On average, milk production after cows were moved was less than what the researchers predicted it would be based on milk production before the move and days in milk (DIM). In other words, production typically dropped because cows were moved. However, on average, IOFC was improved since cows were consuming a less expensive diet after the move.
I was most interested in how diet factors impacted milk responses. The pen moves associated with reduced IOFC and greatest milk loss (over 4 pounds per cow per day) also had the greatest movement in diet NDF (over 3 percentage points higher). Less diet crude protein (CP) (%DM) in the new diet was not associated with a greater drop in milk or IOFC. However, this observation makes sense knowing that it is the provision of amino acids that drives milk production more than simply CP.
Minimizing the impact
On Farm A, when first-lactation cows were moved into a low pen at 197 DIM, milk production did not suffer. This is interesting since extra social stress might have been expected when these first-lactation cows were comingled with older cows. The researchers suggested that these cows also may have had more nutrients than they required for their level of milk production before being moved, reducing any negative impacts of the pen change.
Although this research does not answer all of our questions regarding moving cows between pens, it does show that milk yield can be maintained and that IOFC is often improved by using multiple pens fed different diets. If you are considering moving your cows and changing diets more than you currently are, work with your nutritionist to develop the best strategy. Consider not only ration NDF and CP but also forage NDF, uNDF (undigestible NDF), starch, and amino acids. And, most importantly, evaluate how much you will actually save on the diet when changing pens!