Cow Disposition Rates During the Year

Becky Mills
Contributing Editor

CUTHBERT, Ga. (DTN) -- It never fails. When baby mama puts you on top of the Polaris when you try to tag her calf, you decide she's going on the cull list. Count on it, though, she brings the nicest calf to the weaning pen, and she's bred again.

It appears that it might not be a fluke. Thanks to research done at the Mississippi Agricultural and Forestry Experiment Station Prairie Research Unit by animal scientist Kelsey Harvey, co-worker Jane Parish and grad student Cobie Rutherford, it turns out those hot mamas often do a better all-around job of mothering.

You've probably heard of the chute scores researchers and breed associations use to gauge disposition. A cow with a 1.0 yawns when she leaves the squeeze chute and was likely your daughter's show heifer. The critters that earn a 5.0 will run you over in a heartbeat. The Mississippi team went a step farther and developed a maternal aggression score to see if there is a correlation between attitude and reproduction.

All calves at the Prairie station are tagged within 24 hours after birth. A cow or heifer can earn a 1.0 either by not caring what you do with her baby, or she's so scared of you she runs to the other end of the pasture. A 5.0 will do her best to kill you if you touch her calf.

After five years and 2,000 scores on the Angus-Charolais and Angus-Hereford cross females, Harvey said, "The girls that scored 1.0 only weaned 69% of their calves compared to the females that had maternal aggression scores of 2.0, 3.0, 4.0 and 5.0. That group weaned about 90% of their calves. The cow that eats your lunch weans more calves than the cow who makes your job easier when you're tagging her calf."

"When we looked at calving interval, those cows that were more intense had a shorter calving interval. That makes sense. She's more willing to put herself in the line of fire and fight off predators. That calf probably nursed better. The cow was more attentive and a better mom."

She added, "We don't want cows that are ones and twos because they might let you tag their calf but they're also going to let the wild dog run away with it."

Harvey's personal favorites are the ones that score around a 3.0. "They make me a little bit nervous. I don't necessarily feel like I have to tag the calf in the back of the truck, but I'm also probably not going to turn my back on her for an extended period of time. The cows that couldn't care less might be really great when you're trying to tag their calves because you feel super safe and it's easy, but it's not good for the calf because if she doesn't care about you, she doesn't care about a predator, a wild dog or a big cat. Conversely the females who are really, really mean might be great for predator control, but not great for you. So yes, there's a happy medium there."

BE AWARE OF COWS AROUND YOU

Cobie Rutherford also favors the cows that score a 2.0 to 3.0. "I like the ones that are attentive but not aggressive." He added, though, "Do not let your guard down around any cow. A lack of a fear response means she could turn on you."

For Rutherford, the data is more than just numbers. He runs cows with his in-laws, Mike and Karen Hill, who are in their sixties, his wife, Meghan, and their eight-year-old son, Reason.

There is another piece of the puzzle, however. Although it doesn't seem to be correlated to maternal aggression, a female who sports a bad attitude year-round is probably not a reproductively efficient cow. Harvey said to think about a cow's priorities. There is maintenance, development, growth, lactation, reproduction and fattening, probably in that order. While getting her bred is a necessity for you, it's a luxury for her. When she's stressed, whether it is because she is scared or just plain cranky, her cortisol level increases.

Harvey said, "When this happens prior to an LH surge, her energy goes elsewhere. It's like somebody trying to multitask, there's too much going on, so what we get is a negative effect on follicle maturation and a delay in ovulation. When you're talking about a pre-pubertal animal, we need that initial ovulation to a normal estrous cycle to signal that she's ready to breed. When you're talking about a cycling cow, we need ovulation so she can get pregnant."

DISPOSITION CAN AFFECT PREGNANCY RATE

Yeah, but that's probably just if you run her through a chute to synchronize and artificially inseminate (AI), right? Not necessarily. Although Harvey said the little bit of data they have so far shows when she's out on pasture, the pregnancy rate is about the same for the calm cows and the crazy ones. However, that pregnancy loss is greater and calving rate is less for the wild ones.

"Even though she's getting pregnant, she's not retaining that pregnancy. She's not calving out, she's not taking care of her calf, she weans less calves, and her calves have a lower weaning weight. So even though you're not exposing her to artificial insemination, overall pregnancy rate may not be affected but her overall productivity is affected because she's just weaning a less productive calf or less pounds of calf per cow exposed."

That makes it awfully inconvenient since most of the estrus synchronization and AI process takes place in an alley and/or squeeze chute, where most bovines don't want to be. Harvey said a stressed cow can even take that stress to the pasture, where it has a negative effect on natural breeding, too.

In Rutherford's operation, that not only counts for the safety of his family, but also because he's working toward using his cows as custom recipient cows for embryo transfer. "We try to weed those aggressive heifers out at weaning," he noted.

So, what to do? First, Harvey agreed culling is part of the solution. "Disposition is moderately heritable. You can select sires that are moderately docile and cull your aggressive cows. Cows that come after you are just not worth it." However, she added, "Unfortunately, in spite of what I said about stress impacting reproduction, at least in my own experience, the cows that are psycho always end up pregnant."

And remember, even your pets can take exception to you handling their calf. Rutherford again stressed, "Don't let your guard down around any cow."

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