Everyone has their “reasons” or are they “excuses” for calving when they do. So do we!
I have been in the business over 2 decades. I have a known reputation for change. And also a reputation for not letting “excuses” get in the way of logic and common sense. One change I made was very calculated, and backed by my own studies, observations, and in the end, the pounds of meat in my freezer that simply didn’t lie.

Background:
When we started over 20 years ago, we did what everyone else did, but we were accepting the horror stories of peoples struggles as ‘normal’. With a little more experience now than I had then, I have a much better base than what I did back then. The cows calved beginning in March. Living in Minnesota, that also meant the season of change from winter to spring, mud, snowstorms, and newly emerged pathogens in damp soil.
We did some things like the neighbors, but we also did something they may not have. I wrote everything down. Since we bought bred cows to start, we were stuck with the situation they used. It wasn’t bad, but it was not without flaws either. Management was the key.
Awakening:
After years of observing and trialing things, earlier, later, we wavered around for years. As I watched my notes, a general trend showed loud and clear. It was in the performance of the cattle.
This is a few of the things I noted for each animal.
The calf:
*Weather at birth *time of day born *any illness or treatment given * performance data *weaning weights *yearling weights *meat quality *if they were kept as replacements
The Cow:
*her breeding cycle (calving to calving) *quality of calf produced *meat quality of calves harvested *how well she matched the sire used
The Sire:
*Consistency of his offspring *Traits directly from the bull noted in the herd (not always seen till year 3-4)

Calf A Born March 20
Dam Missy, a mature cow, 6 year old. bull calf. Calf weight at 205 days 390. Calf had been noted as hard navel- treated, born 2 days after rain. in the barn.
Calf B Born May 14
Dam Lucy, mature cow, 4 year old. bull calf, calf weight at 205 days 440. calf noted as bull prospect. no treatment. born on pasture.
Weights were taken monthly thru the winter post weaning. Calf B was much lighter at weaning time (due to his age) than calf A, but the rate of gain ratio was significantly higher especially as the calf got close to his 205 day. Both calves were castrated, the Calf B passed up Calf A about 30 days post weaning, and his curve was significantly better than calf A.
Having compared the meat quality at processing, we found that calf B had significantly more marbling, despite the close relation of the bloodlines of the cows and calves having the same sire. This scenario played out with calf after calf.
I had consulted with a few other cattlemen who calved in May-June. Their years of experience echoed what I was observing in my own herd.
Skeptic:
I was VERY reluctant to push my cows back to May calving. I had all the common thoughts: It will be hot when the bulls need to breed. The flies will be bad. Late calves will be really late. We will need to adjust our land management to calve on pasture. I would be checking cows in the pasture instead of in the barn. Would predation be an issue. How will I get cows in if they have a problem.
I also was facing these thoughts: 3rd trimester for the cows will start AFTER the worst of winter is over. We can tighten our calving season by selling the fall/late cows. We can leave calves on the cows longer and creep feed hay. Bulls will be producing the sperm they will use when the weather is more favorable. Our steers will be ready for processing when prices are higher at the summer markets.

The Results are IN: Comparing before we switched to 5 years later numbers
Having 5 years under our belt, and counting the larger herd we now maintain to what we had previously, everything has changed. I have only used my chute for calving 1-2 times per year since we switched. We are calving more heifers than ever before, and they are calving with the herd on pasture. (we are only breeding a very few yearlings, mostly because I like them more mature at first calving) The young cows are well out performing the prime aged cows originally born in March/ April.
The steers are finishing larger, younger, and with even better meat quality than ever before with great consistency.
We tightened our calving season to 60 days. we have very few open cows, and about 70% or more calve in the first month of the season. (It seems a large bolus of cows come in heat within a few days before we put the bulls out every year) The bulls can handle way more cows than I give them credit for! (70-90/ mature 3+ yo bull)
We manage our pastures a little different, and the cows teach their calves to rotate with them very willingly. Illness is almost non-existent. Calving problems dropped from herd average of 6% to herd average of 1-1.5%. I don’t need to check cows as often, they seem to be just fine.
We use about 6-8% less feed. Thru the winter months. I have noted we treat less than 1% of calves for illness thru their first winter. It’s less than .5% for a herd average after that. Fertility levels seem to be up in females. I need more documentation to confirm.
Our bulls produced have proven themselves well worth the wait to grow up an extra year. Growing out naturally. They are holding up well for us and those who buy from us.

In Closing:
Do what works best for you, but if you wish to do what might be best for your livestock, keep some records and see what happens. It’s the only way to find out for yourself.