Driving dry matter intakes on dairy farms
FT. ATKINSON - Change is happening with dairy cows and dry matter intake.
Dry matter delivers the amount of nutrients an animal needs, providing her with organic matter that contains the digestible nutrients necessary for microbial yield to supply her with energy and nutrients.
"It's a really nice cascade that says dry matter, really, has huge impacts," Dr. Mike Hutjens, University of Illinois, said during the "Hoard's Dairyman" August webinar, sponsored by Diamond V.
Higher dry matter intake (DMI) can reduce or raise feed costs, improve or reduce economics, and change feed efficiency for the better or worse. "Certainly, a lot of important things circle around dry matter intake," Hutjens observed.
DMI continues to be a leading contributor to calf growth, cow health, lactating cow productivity and, thereby, dairy profitability.
But research is exploring nutrigenomics, the notion that nutrients fed to dairy cattle may impact gene response by genes being turned on or off.
Examples include higher nutrient intake for pre-weaned calves to produce more milk in the future and adding rumen-protected methionine to up-regulate fertility and immunity. "Certainly, this whole area of nutrigenomics is really exciting," Hutjens said.
With lactating cows, the goal is to optimize feed efficiency, which fuels milk production. Remember that it's the pounds of nutrients consumed that's key, not the pounds fed or the ration composition, Hutjens reminded farmers.
The math is simple: one pound of DMI produces 2 to 2.5 pounds of milk. In turn, DMI is driven by milk yield and, secondarily, body weight. Hutjens cited studies that shows, as milk production goes up, DMI really climbs, which is not the case as body weight increases.
Fresh cow research reveals first lactation cows start out eating less than mature cows and gear up at a slower speed. "This screams at us that these animals are different," Hutjens said. "Therefore, if you can split fresh cow pens into young cows and older cows, wow, I think you have some real opportunities in terms of meeting their requirements."
Even the last few bites count. That "last" pound of dry matter consumed can support two pounds more milk, Hutjens noted.
Cows stop eating for a variety of reasons, ranging from empty feed bunks to fats in the ration, issues with lameness or heat stress, and getting physically full because of the size of her body or stage of her pregnancy.
In addition, cows dealing with metabolic challenges, like subacute rumen acidosis or ketosis, will not eat up to their potential.
With dry cows, focus on managing body condition scores (BCS) and the risk of metabolic diseases. it's important that dry cows maintain a healthy BCS, Hutjens stressed. They should be fed a consistent ration, generally at 2 percent of their body weight, up to calving.
Dry period nutrition is all about energy. "You want not too much, not too little, but just right," he explained, offering a goal of 90-110 percent of a cow's requirements consistently and with all other nutrients adequate.
Non-moldy straw can be added to control energy intake, with wheat straw the most popular because it's low energy, floats and has residual time in the rumen. To avoid sorting, process to one inch in length.
For growing Holstein heifers, focus on growth patterns, the cost of raising them, and maintaining a healthy BCS.
Aim for a daily gain of 1.7 to 1.9 pounds until calving. At that point, the heifer should be between 22 and 24 months of age, stand over 56 inches tall at her withers, and chart between 3 and 3.25 BCS. After calving (decalfinated), she should weigh 1,250 pounds.
Don't let heifers get too fat, Hutjens stressed. Besides efficiency losses, too much weight translates into economic waste and the potential for metabolic and reproductive issues in the future.
The challenge with pregnant heifers is that they physically aren't capable of eating as much as mature cows, Hutjens observed, but their nutrient requirements are higher because they're growing and pregnant.
The goals for the pre-weaned heifer are to double her birth weight before weaning, to develop her rumen structure to maximize dry feed consumption, and to enhance immunity and health, all in an economical manner..
Hutjens advised focusing on nutrigenomics, the understanding that the plane of nutrition impacts an animal's genetic ability to perform at its potential. "Poor feed management early on can hinder good genetics throughout life," he explained.
In summary, since dry matter impacts growth, fertility, metabolic disorders and longevity, Hutjens advises dairy producers to determine the optimal DMI for each group of dairy cattle on the farm.