A while back I was studying a book that was thoroughly written and heavily touted as a history of settling of the Cumberlands. The North American Indians of the East and South played a gigantic role.
Indians had several disadvantages when it came to struggles over land. Population and the endless migration of Americans and Europeans usually outnumbered Indians in short order. Lactation anestrus was an important deal after European diseases had decimated the population of North American natives by maybe 80%. I’ll attempt to explain.
The Scotch-Irish settled most of the Cumberland Plateau, which stretches north from Birmingham, Alabama, to Canada. Their women regularly had a child every 20-24 months. Most Indian women had a child every four to six years. Lactation anestrus and persistence of lactation limited the native peoples to four or five children per 20 years while a lot of whites raised eight to 12.
Related to this is “persistence of lactation,” which can be defined as the period of time that a mammal produces a “significant” volume of milk. In cattle, remember that milk is an anti-maternal trait when compared to reproduction and longevity. Milk and lactation are critical: But more and longer tend to go hand in hand and more is usually not better. Actually, more is generally worse.
One graph that even I can understand and remember is the old one of a Jersey cow that calves and comes into lactation. It tracks the production of her and three or four other cows over the next 300 days. On this graph, the cows varied as to the day they reached their maximum milk yield from 30-90 days. There some critical learning points for us to remember:
First, cows that peak early (30 days) also persist shorter (less persistence of lactation). Typically, they tend to self-wean their calves or have calves that are easy to wean. Their calves tend to graze more aggressively and select for a wider variation of plant species. They learn the ropes.
Second, cows that peak later (60-90 days) give much more milk both at peak and during the 300 days. They have longer lactations.
Persistence of lactation also increases milk production per lactation.
However, that old graph fails to show the facts that high persistence in lactation is anti-reproductive and anti-longevity, which are quite likely the most important maternal traits, and quite arguably the most profit-driving traits.
Further, milk production is heavily genetic. Mankind has viewed cow’s milk (plus goat and sheep milk) as a near perfect food for thousands of years. Cows and goat and sheep milk took lots of pressure off the two-legged mamas to nurse for years. North American natives did not make a habit of milking animals.
It resulted in the two-legged females being more fertile while the four-legged girls often gave up time and grade. There ain’t no free lunches. Somebody’s got to pay. Cheap feed and work were the common answers and payment.
Pride has always been destructive to mankind unless it was well bridled and controlled. Any show-cattle ring at every county or state fair proves my point. Judges (usually hand selected from out of state universities) place the freaks at the top and then give their reasons. The bulls are usually carrying too much long hair and body and finish. The heifers are big and fat and long and hairy. Ditto the same for the cow with a very sizable udder to boot. Usually everything is post-legged and straight-backed. They spend more time setting them up than they do walking around. Notice there are not any 14- to 18-year old cow classes.
If you are new to this business and want to learn fast how to not go broke I recommend that you go to a sizable cattle show. Then listen to the judge and take pictures. Go home and select for the opposite and review the pictures regularly to see how you’re doing. Also, read Walt Davis’s book “How to Not Go Broke Ranching” and his new book “Cerebral Ranching” twice each.
My take home message for ya’ll is that high milk production results in extended persistence of lactation which yields weaning and health issues in the calves. In the middle there are breed-back issues and often fetal deaths. Forages in few locations yield enough energy and minerals for long enough periods to support more than six to seven quarts of milk per day with a 40-day peak in lactation. This peak lactation needs to arrive 8-10 weeks post green-up, with strong grass in the pastures.
High butterfat is more important than high milk, and lower-producing cows tend to give higher percentages of butterfat. If your cows look like they need to go through a dairy barn when their calves are 30 to 60 days old spend a little time thinking about persistence of lactation. Calves work and wean because of less milk, not more. Cows that milk hard keep hard.