One Chance to Grow ‘em Right

There’s a mantra among heifer growers that’s being proven time and again: You only get one chance to grow heifers right.

If heifers are well grown and are bred and conceive on time, they can go on to do amazing things. If they don’t, it’s a lost, lifetime opportunity of what might have been.

“Will under-grown heifers not do anything? No,” says Jill Davidson, director of dairy research at the Purina Animal Nutition Center near Gray Summit, Mo. “Under-grown high genetic animals will perform, but the question is, will they do everything they could have done? It’s really a question of lost opportunity.”

Her goal is to have 75% of heifers reach a hip height of 45” at puberty between eight and 10 months of age, and reach 52” to 54” of hip height by breeding age at 13 months. They should weigh from 550 to 650 lb. at puberty, and 800 lb by the time they’re bred.

The key is not what the group averages, but how many total animals are achieving the height and weight targets. To achieve optimal lifetime performance, it’s critical as many heifers as possible reach these goals.

If they’re achieving that growth, they can be bred at 13 months and calve at 22 months. The target is to have 85% of heifers pregnant after three estrus cycles. “If you have 1.7 services per conception, you’ll see 80% pregnant after three services,” she says. 

High Performing Cows

Well-grown heifers develop into high performing cows. At the Purina Animal Nutrition Center, Davidson compared cows that were peaking above 140 lb versus those that had peak milk below 140 lb. About a third of the Purina herd was in that high-peak group.

There was a 20 lb/day difference between the average peaks of  two groups. The rule of thumb is that for every 1 lb of additional peak milk, a cow will produce an additional 250 lb of milk in her lactation. And that’s exactly what happened: The high peaking group produced 5,000 lb more milk over their lactations than the low peaking group.

Since the Purina Animal Nutrition Center focuses on research, one could argue these cows have an advantage. But all the cows at the Purina Center are placed in research trials on a randomized basis, so they have an equal chance of being in a treatment group or a control group.

But even the control groups are fed at a high level. The high group’s “control” ration is balanced for 110 lb. of milk and 55 to 57 lb. of dry matter intake. The top producing cows in this group will have 63 to 64 lb of intake, says Davidson.

Most of the cows peaking above 140 lb of milk had feed intakes surpassing 60 lb, and many maintained that rate of feed intake deep into lactation. Those cows peaking below 140 lb. rarely saw their intakes top 60 lb, and many dipped below 50 lb after 200 days in milk.

Davidson took the analysis one step further, and looked at cows peaking above 150 lb/day. The Purina herd had 18 of these animals: two in their second lactation, six in their third, six in their fourth and four in their fifth lactation.

“This shows we can have longevity without burnout,” says Davidson. These 18 cows represented about 5% of the herd with two or more lactations, which is about double the national average.

Eleven of these animals had been on a partially accelerated calf feeding program, and seven of them had been on a fully accelerated program. They also had all participated in transition cows studies, both pre- and post-fresh.

There are two points to this analysis:

• Well-grown and well-managed dairy cows can do amazing things as evidenced by the top performers in any herd.
• “We cannot just consider the average performance, but need to recognize the magnitude of variation in response to our management decisions, environmental impacts, as well as nutritional changes,” says Davidson. “Controlling our processes to create consistency should drive success!”   

Note: This story appears in the May 2017 issue of Dairy Herd Management.