Curiousfarmer

Some years we can’t remember helping a single calf nurse.  This calving season has been difficult, with one problem after another.  Sometimes we have had more than one problem pair in our corral, which is where we keep the pairs separated if they are having problems until they can be on their own.

Admittedly, a big source of our problems this year has been our decision to keep and calve very old cows.  Cows that are productive into old age is a nice problem to have, and one that I largely attribute to a better nutrition and feeding strategy.  Better rotational grazing has improved the green season nutrition, and unrolling round bales of hay has improved the winter nutrition.  Unrolling the hay instead of feeding in feeders reduces the competition with younger, stronger, cows, and it is also easier to chew as the hay is loose after unrolling instead of packed densely.  Older cows teeth wear down, resulting in more difficulty chewing which can become a nutrition issue.

Unfortunately, older cows udders break down over age and the teats become larger, sometimes resulting in teats so large a newborn calf fails to get started nursing.  We get the pair into the corral and the cow in the catch chute and help the newborn calf nurse.  Usually one or two nursings will be enough for the calf to get the idea and start nursing on its own.  When we see the calf nursing on its own, we turn the pair back out to pasture with the herd.  Annoying, but doable.

But the problem which has baffled us this spring and a couple of times in the past few years, is when a heifer calved without problem, but failed to produce any or enough milk for her newborn calf.  Until a few years ago, we had never seen this problem.  But it has happened again, and this time with this beautiful heifer, 527, pictured above.  We called our local vet and she took the heifer’s temperature and palpated her udder, assuring us there was no discernible health issue.  The udder is soft, not hard as if it had mastitis.  And there is no pussy discharge, just nothing.  The vet didn’t have a theory, which is frustrating, but also a relief that the heifer wasn’t sick and we weren’t having a disease problem.

So we started brainstorming.   What is different about our herd?

Genetically, the base breed going back to my Grandfather’s cattle was Shorthorn.  We used some Lincoln Red genetics in the 80s and 90s, an ill-advised foray into Maine Anjou genetics in the 90s, and finally, when we could no longer find good Shorthorn bulls, we started using Red Angus genetics around the year 2000 and have been very pleased with the results.  Our cattle are moderate- framed, thick-made, and able to finish on grass, which worked great when I began to direct-market grass-finished cattle around 2008.

Red Angus genetics didn’t seem to change the udders of our cattle very much.  I would say the conformation of the udders would be a little better and they give a little less milk.  Shorthorns are known for producing a lot of milk for a beef breed, so it makes sense that Red Angus would decrease the amount of milk, but not by much. I don’t think the problem is genetics.

We have improved our pastures and especially the rotation and resting of the pastures as we’ve implemented our own version of mob-grazing.  And we’ve started grazing some hay pastures during the summer slump when some of the cool season grasses are growing very slowly.  The end result is our cattle are gaining better than they ever have, with some of the fastest-gaining calves gaining close to 3 lbs per day from birth to weaning.  We recently viewed an old vhs tape of our cattle in the 80s, and the difference was remarkable.  Without video evidence, we never would have believed how much better the pastures and how much thicker our cattle are now.

Why am I writing about how fast the cattle are gaining?  Sometimes I have an insight or notion which I’m not sure where it comes from.  Maybe I read something sometime.  I don’t know.  But I woke up one morning with a theory that the reason these heifers have no milk is that during a critical stage in their mammary development, they were gaining weight so rapidly, instead of normal mammary development, their udder became fatty.

I asked the vet and she didn’t think it made much sense.  We even stopped in one day and visited our old retired vet from Mineral Point, and he didn’t think this theory made much sense.  Undaunted, I was going to put this theory onto the internet and see if any of you concurred.  But a little research, and a few key articles later, of which I will link to, I’m 99% sure this is what is happening to these heifers.

The reason we need to decide on a theory is because it will affect our decision making.  If for some reason these heifers are genetically deficient in milk, we would want to purchase bulls with higher milk epds, (expected progeny difference).  But if my theory is correct, and these heifers are actually receiving too much nutrition, then we would want to select bulls with lower milk epds.

The first article I found that pertained was written by University of Illinois extension in 1999.  They talked about the five different stages of mammary development and how sometimes mammary development is isometric, (growing at similar rates as the rest of the body), and other times mammary development is allometric, (growing at two to four times the rest of the body). A key allometric stage is prepuberty, 3 to 9 months of age.  This paragraph was particularly illuminating:

“Prepubertal nutrition can have a significant effect on future milk yield. Raising heifers on high planes of nutrition during prebubertal mammary growth has been shown to have a negative effect on milk yield. Feed restricted heifers can have up to 30 percent larger mammary glands at puberty. Furthermore, mammary tissue on heifers fed ad libitum was over 80 percent fat, while heifers fed a restricted diet have around 65 percent fat, and 13 percent more parenchymal tissue (tissue that will eventually become milk producing tissue) compared with heifers fed ad libitum. It should be noted that mammary parenchymal tissue grows into a layer of fat referred to as the fat pad.”

Ok, are you convinced yet?  I also found this article published in Asian-Australasian Journal of Animal Science.  Both articles are written pertaining to the dairy industry, as most dairy heifers are raised in confinement on a diet that can be regulated.  They suggest a feeding strategy which restricts the diet at critical times during mammary development, and then more feed at other times so as to not waste time and money as the sooner a heifer is producing milk, the more profitable the industry feels the dairy producer will be.

However, I’m wondering if the dairy industry is thinking about this wrongheaded?  A big problem in the confinement dairy industry is how quickly cows are “burnt up”, (culled for one reason or another).  I used to think the reason that cows fell out of production so fast was because of the way they are managed as cows.  But actually, dairy cattle are on a fasttrack from birth.

Maybe the dairy industry should go to a policy of raising their replacement heifers slowly on a high forage diet.  Maybe they shouldn’t worry so much about rushing a heifer into production by age two, and instead should be satisfied with a heifer calving at two and a half or three years of age?  Most of the big dairy farmers in my area are outsourcing the raising of their dairy heifers.  There may be an opportunity for farmers to do a better job with this?  I don’t know.

As far as our problem, so far we have had a very few that exhibited this problem.  I would hate to change the way we are managing our cattle and pastures as the whole herd is doing so well with our rotational grazing.  I’m thinking our problem is rare and only affecting a very few heifers that may be very early maturing, thereby coinciding the allometric mammary growth phase at just the wrong time when they are gaining 3 lbs per day.  Not sure, but I will continue to monitor.