Those who think that the weight gains made in their dairy heifers are not important should think again.
Average daily gain is something that beef producers have used for years to measure their calves' progress, but most dairy farmers haven't paid too much attention to it. Richard Wallace, DVM, senior veterinarian for dairy with Zoetis notes that one extra pound of average daily gain in heifers can mean as much as 1,550 pounds of extra milk in the first lactation.
He cited studies showing that improving heifer calf growth rate can mean almost 2,300 pounds of milk in the first two lactations combined.
He urged dairy producers to take another look at that part of their operations and understand the economics.
Researchers at Cornell University took data that had previously been collected and studied it again — called a retrospective study. They looked at the weights of dairy heifers at birth and weaning, at energy intake over maintenance requirements, age at first calving, average daily gain and milk output in their first and second lactation.
Data from 1,244 heifers was part of the study. They concluded that every pound of average daily gain as pre-weaned heifers meant an additional 1,550 pounds of milk in that first lactation.
The conclusion, at today's prices, means that farmers could spend $1.25 more per calf per day and still come out ahead, Wallace told a group of dairy clients for Lodi Veterinary Care at a meeting last week.
That was without factoring in improved health of those calves that are growing faster as well as reduced treatment costs.
Wallace said this study was one of several showing how important it is to maximize the gain of dairy replacement calves on the farm and the use of accelerated calf feeding programs.
A beef calf which is raised by its mother will eat four to eight times a day, getting three pounds of solids per day from the cow's milk. That's 28 percent protein and 26 percent fat on a dry matter basis.
Most dairy calves, by contrast, will get a gallon of milk — one pound of dry matter per day.
Beef calves will be born at about 70 pounds and will weigh 600 pounds at six months of age. Large-breed dairy heifers will weigh 85-100 pounds at birth and at six months will weigh 350-400 pounds, he said.
Wallace suggested some of the things dairy farmers might want to do to up their heifer calves' gain levels would be to use a milk replacer with higher levels of fat and protein or even consider using cow's milk. Adding a meal or meals to the calves' day could be even more important.
Beef calves are hungry every four-six hours, he noted, and it's no different for dairy heifers being raised in individual pens or hutches. When they are hungry they will suck on things in their environment so it's important that their areas be clean.
If they suck on dirty pens or buckets it's more likely that they will get diarrhea, which will set their gains back some more.
If starter grain is present for the calves — and it should be — it's important that they also have water available. Wallace said this past winter made it tough to keep water there for calves but having it there is part of the equation for making sure the calves gain weight well in their first 18 weeks.
"Maybe you need to come back 20 minutes after calf feeding to feed the calves warm water to go along with the calf starter that should always be in front of the calves."
During the cold weather calves' maintenance requirements rise significantly and it's important to meet those requirements as well as provide additional calories for the calves to grow.
Wallace said a study comparing calves fed cow's milk to those fed a 20 per cent protein, 20 percent fat, milk replacer found that the death rate was lowered significantly on the cow-milk diet.
"Remember cow's milk is 28 percent protein and 27 percent fat on a dry matter basis."
In cold weather it's good practice to add another meal for the calves during the day. That's a better alternative, he said, than concentrating the milk powder and feeding the calves "milk shakes."
"Added ingredients like that are not as good as feeding them a third meal during the day."
Housing is another important factor in getting good gains from dairy calves. Their housing needs to be clean, dry and draft-free with good air quality, he said.
There is now what veterinarians are calling a "nesting score" for calves' ability to nestle down into the bedding of their pens — preferably straw in the colder weather.
Wallace said the use of blankets or jackets on calves helps them reduce their maintenance needs because it's preserving their heat — they don't need added energy to make up for the losses to the cold.
"Calves have no natural body fat when they're born and they will need energy to make up for any losses they have," he said.
The best vaccination any calf can get, says Wallace, is colostrum. The quality, quantity, timing and lack of contamination are all important when it comes to getting this first milk into the calves.
Getting calves up and going at birth is an important part of racking up the good daily gains that are going to be needed to produce a top-quality dairy cow.
There are also lots of ways to lose that advantage, he said.
Calves with pneumonia in their first three months were found to be 2.5 times more likely to die after 90 days of age.
Heifers with scours were 2.9 times more likely to calve later.
Wallace said there are several theories as to why these calves with higher gains will produce more milk as adults. One of the theories is that well-grown calves see a reduction in subclinical disease.
"These calves will handle disease exposure much better."
Wallace said there may also be what is called an epigenetic effect — the calves' have genes that are "turned on" by the full diet they are given as calves.
"This up-regulates the good genes, allowing the animal to more fully express their genetic potential. There's probably an effect from both of these factors."