My education continues! We used an Angus bull and a South Poll bull to breed our Red Angus heifers last year. Both bulls had actual birth weights reported in the 50s, so I was confident we wouldn’t have calving difficulties. South Poll doesn’t have EPDs, but the Black Angus had calving ease and birth weight EPDs in the top 1% of the breed, giving us even more confidence.
Since the Black Angus is homozygous black, I knew I would be able to tell parentage as the black calves would out of Blackie, the Black Angus, and the red calves would be out of Teddy, the South Poll. I planned to weigh all the calves at birth and keep records, figuring this would be a fun real world experiment.
I predicted each bull would sire roughly half the calves and the birth weights would range from 50 to 70 lbs for the Angus and 50 to 80 lbs for the South Poll. I optimistically predicted no calving difficulties. 19 out of 20 heifers calved in April and May.
The first surprise was the number of calves sired by each bull. The South Poll sired 18 out of the 19 calves. The one calf out of the Black Angus was a nice little heifer, 54 lbs, no surprise there. But the South Poll surprised us with larger than expected calves, especially the bull calves.
The top photo shows our first calf out of Teddy, an 80 lb bull calf, born April 7th. I let the heifer work for a while and she had it on her own, but it was a hard delivery. The calf’s face was slightly deformed from dystocia.
The next photo shows Isabel holding an 82 lb bull calf. Beautiful calf, but too big for my liking. And they just kept getting bigger as spring pasture improved. We had four hard pulls with two dead. The calves we pulled were 88 to 95 lbs. Nine bull calves averaged 88 lbs with a range of 80 to 95 lbs.
The last bull calf was born unassisted, but I didn’t get him caught to weigh. He’s in the bottom photo and probably weighed around 80 lbs.
The heifers out of Teddy weren’t too bad, averaging 69 lbs with a range of 62 to 76 lbs. We also had twins out of a heifer, the first time we can ever remember that happening for our farm, with the bull calf weighing 65 lbs and the heifer weighing 50 lbs. I didn’t include them in the averages.
I wrote an article for Stockman Grass Farmer about crossbreeding and potential calving wrecks, but it appears I had to learn the lesson for myself, a lesson I won’t soon forget. I shouldn’t blame crossbreeding, as animal scientists report only around a lb and a half increase in birth weight due to hybrid vigor. But I do think South Poll, being a composite breed, probably passes more variability to its offspring? Otherwise I’m not sure how to explain the large birth weight calves.
We almost never buy females, choosing instead to raise from within our herd, so I know the heritage of our heifers includes some large birth weight calves and trouble calving. But I was counting on some prepotency from Blackie and Teddy to give us small calves with no calving difficulty. I believe both bulls come from honest herds, so I’m not questioning their actual birth weights in the 50s. I’m just surprised I guess, but that’s farming and life. Keeps life interesting.
Curiousfarmer 