Dairy Reproduction Troubleshooting
(Continued from Page 14)
O’Connor. Calcium, he said, is very important to muscle
contraction.
In addition to calcium, phosphorus has been traditionally
linked to reproductive performance by a 1950’s study. How
ever phosphorus intake is not a problem today, as studies
now show that phosphorus levels are not as much of a factor
in reproductive performance when cows are fed a good diet.
In a more recent, 785-cow worldwide study, researchers
found that there is little or no difference in reproduction
when the herd ingests normal or excessive levels of phos
phorus.
In addition, lowered phosphorus levels did not affect the
milk yield or bone strength of the cows.
“It’s costly to feed that much phosphorus,” he said,
adding that in addition to cost, high levels of phosphorus is
an environmental concern with nutrient management.
“I’m not up here to say you have to use hormones to get
your cows pregnant. There are plenty of systems out there.
As in all of life, the better ones seem to be the more compli
cated ones. I’m going to present results to whet your appe
tite, but let you make the decision,” said O’Connor.
A producer’s objective should be to develop a plan to get a
high percentage of the cows pregnant in early lactation. A
New York study found that if a cow comes into heat early,
she will have a better first service conception rate.
“The more cycles a cow has prior to the time you want to
breed the cow, the higher your success rate at the first ser-
Breeding Systems
vice,” he said.
Only 50 percent of heats are detected in the U.S., and 5-15
percent of cows are not in heat when they are bred. Accord
ing to Cenex figures, the conception rate in Pennsylvania is
33 percent and the pregnancy rate is 15 percent.
“Producers are breeding cows not in heat or not catching
them in heat because it’s a labor-intensive chore,” said
O’Connor. The benefits of estrous synchronization may help
alleviate some of these problems.
The “Monday Morning Program” is a 14-day, two
injection plan. The cows are injected with prostaglandin
(PC), come into heat, and then bred. A “set up shot” will
help the cow be more likely to respond to the breeding shot,
said O’Connor. The PC shot is administered 14 days prior
to the end of the voluntary waiting period before the cow is
back in the breeding program.
For instance, if a producer waits 50 days before rebreed
ing a cow, administer the shot 36 days before the end of the
waiting period. “A higher percentage of the cows should be
in heat after the breeding shot,” he said.
The popular ovsynch program, combining prostaglandin
and the GnRH hormone, now costs less than in the past. In
fact, a half-dose of GnRH will suffice “if you can consist
ently deliver the smaller dose,” he said.
(Turn to Page 16)
Monday Morning
Program
Ovsynch Program