Dry matter intake impacts the growth, fertility, metabolic disorders and longevity of dairy cows.
“Dry matter intake really drives the nutrients that animals get,” said Mike Hutjens, University of Illinois dairy specialist emeritus.
“There are a lot of important things around dry matter intake,” Hutjens said during a Hoard’s Dairyman webinar. “You can raise or lower feed costs, and you can change feed efficiencies.”
For the lactating cow, the dry matter curve peaks out slightly behind the milk production curve.
“As a result, animals lose body weight, and that becomes important in terms of animal health, immunity and fertility,” Hutjens noted.
Each one pound of dry matter equals 2 to 2.5 pounds of milk.
“Milk yield really drives dry matter intake, and body weight is a secondary factor,” Hutjens said. “As milk production goes up from 60 to 88 pounds, the dry matter really climbs.”
Heifers and cows are different for dry matter intake right after calving.
“Heifers start out lower than cows, and they go up at a slower weight than cows,” Hutjens said. “So if you have a large enough herd, you can split the fresh cow pen into young and older cows, and you will have some real opportunities to meet their requirements.”
Feed Efficiency
The marginal dry matter intake is the last pound of dry matter the cow consumes.
“That should support at least two more pounds of milk because you have already met her maintenance and growth requirements,” Hutjens said.
“If one pound of dry matter costs 10 cents, you get two pounds of milk that is worth 32 cents with $16 milk. That means I put 10 cents in and got 22 cents back,” he said.
Minimizing sorting can impact the dry matter intake of cows.
“You need to reduce the long forage particle size to less than 2 inches in length and add water at seven to 15 pounds per cow,” Hutjens advised.
Feeding cows more frequently may decrease feed sorting.
“If you feed your cows once a day and go to twice a day and the cows increase their intake by more than two pounds of dry matter, you should stay with the twice-a-day feeding,” Hutjens said.
Digestible NDF drives digestibility and nutrient availability.
“Undigestible NDF may determine nutrient fill from forage sources,” Hutjens said. “That’s why some farmers feed straw to try to get slow down to meet the minimal fiber requirements.”
Dietary Strategy
Dairy efficiency equals the pounds of 3.5 fat corrected milk divided by the pounds of dry matter consumed.
“I think this is a tremendous tool, and 1.5 is a nice target to shoot for,” Hutjens said.
For dry cows, he said, the goal is a “Goldilocks” diet.
“You want to provide just the right amount of energy,” he said. “You want the cows to eat 90 to 110 percent of their requirements on a consistent basis.”
The 18 megacalories rule means close-up cows need 18 megs of net energy per day.
“When a cow eats 30 pounds of dry matter, she meets her energy needs, she is physically full and her rumen is functioning,” Hutjens said.
“If you’re going to use straw or low-quality hay in the diet, you need 1,100 to 1,200 grams of metabolized protein or the cows will be short on amino acids,” he noted.
To avoid sorting, most dairymen pre-process the straw.
“For straw, nothing should be longer than one inch,” Hutjens stressed. “And watch for mold. The last thing I need in my close-up cows is moldy feed that affects the immune system.”
Proper Nutrition
The ration for growing heifers should provide enough nutrients to make sure the animals are growing to hit the target weights for heifers at breeding.
“If the mature body weight of your cow is 1,400 pounds,” Hutjens said, “she should weight 800 pounds at breeding and 1,250 pounds at calving.”
Heifers still are growing during the last two months before calving.
“On many farms, because we aren’t getting the right nutrients to the growing heifer, she stops growing, and they come in under weight, as well,” Hutjens said. “Plus the heifers are developing their mammary gland and producing colostrum as they get closer to calving, so the nutrient requirements increase quite a bit.”
The goals for pre-weaned calves are to double their birth weight prior to weaning, as well as develop their rumen, build immunity and do all those things as economically as possible.
“The accelerated calf liquid program can be whole milk or milk replacer,” Hutjens said.
“You should cap the milk solids at 2 percent of the calf birth weight,” he advised. “If you have a 90-pound Holstein calf, feed her 1.8 pounds of powder in seven quarts of liquid.”
The amount of liquid is capped to encourage starter intake by the calves.
“If you’re going to use milk replacer, it must be similar to whole milk at 26 percent crude protein and 15 percent fat,” Hutjens said.
Source: Agrinews
