Over the years, I have come to believe that the efficiency of converting feed to milk is perhaps the key indicator of dairy profitability. It is certainly the most important on an individual cow basis. When looking at this important ratio and other metrics on a whole-herd budget for the dairy, several other points of measurement will determine the overall financial well-being of the business.
When I think about formulating diets, though, we really are thinking about one cow and the conversion of purchased feed material to saleable milk components. Thus, the efficiency of that conversion is paramount. It is where the economics of buying and selling things actually generate a profit or not. We know that feed conversion changes as a cow proceeds through its lactation. In early lactation, weight loss is figured into the actual building blocks to make milk. This obviously helps efficiency, although the body fat being mobilized did incur feed cost in the previous lactation or in the dry period. In late lactation, weight gain hurts efficiency of milk produced. And don’t forget to correct milk for solids content before calculating milk to feed conversions.
With a dairy full of various animals at all different stages of lactation, milk production, and body weight change flux, we end up formulating diets for the average cow of a group. It is not perfect, but knowing that in addition to the actual diet composition, we can recognize that individual animals regulate their own feed consumption to supply more or less daily nutrients than were planned for in the diet. It is a good system! In high production pens where you expect the average cow to be losing weight, we include that expectation in the way we describe the cow to the formulation model. The same is true of the later lactation group where weight gain is indicated and is expected to use up part of the nutrients consumed.
What should we do when the cow’s appetite and thus actual intakes are in excess of what we have planned for? This question seems to be a hot topic at the moment as there has been much discussion this fall about why cows are eating so much. As we look back in time, more intake was seen as mostly, if not entirely, positive. I can think of many products offered into rations that had data to show a raise in dry matter intake (DMI). Wow! That is good, we always thought. More intake means more milk. Right?
Well, what about when it doesn’t? And also, much of this convention of thought was derived when feed was 8 cents per pound of dry matter. Does the same hold true when feed cost in some regions can approach 20 cents for that same pound? We need to do the math on that. No matter what the math says, though, it seems at times that slowing down intake is a difficult task.
Which drives which?
So then, why do the cows seem to be eating more feed? I remember a few years back when I used to tell clients that until they have an individual pen eating at or above 60 pounds of feed, they wouldn’t be happy with their tank average. Now, for high pens, 60 pounds is clearly in the rear view mirror. These intakes are for Holsteins, but the principle is the same for Jerseys and crossbreds. Is this good or bad? More intake means more feed cost. But milk is up even more, and most dairies we see have improving feed to milk conversions.
There have been conversations recently about the escalating speed of genetic improvement that is likely driving most of the improvements in milk and thus intake. Or, is it intakes and thus milk? In classic chicken or the egg fashion, I am not sure if intake drives milk or milk drives intake. I expect a geneticist that is involved in this rapidly evolving area of our industry would perhaps know the answer. For me, as a nutritionist, I just need to be sure we are keeping the same or better feed conversion as these two key indicators at a dairy both seem to keep going up.
When the new NASEM (formerly Nutrient Requirements of Dairy Cattle) was released a couple of years ago, one of the much discussed improvements were related to better predictions of dry matter intake. I appreciate the accomplishment via research and modeling to better predict intake using so many pieces of information from the diet, the cow, and the environment. Still, for me in my real world, if I am honest, cows sometimes just seem to eat what they want. Having said that, more is usually better, but not always.
It should be said that on the dairy level, measuring actual intake is not easy. We take the numbers at face value, but we know that things like wind, shrink, scale issues, feeder error, pen count errors, weighing of refusals, and, most importantly, the dry matter content of everything involved are sometimes all over the place. We work in an imperfect world at best. It is true that the most error-prone factor is incorrect dry matter/moisture content of wet feeds. To an outsider, the pervasive use of the term “dry matter intake” instead of simply intake would seem strange. But when understanding the variable moisture content of so many of our feed ingredients, it isn’t surprising “dry matter intake” rolls off the tongue of any dairy producer like the days of the week.
Back to intake in recent fall months. I have been paying close attention, and it is true that most dairies are getting as much milk as ever; thus, we shouldn’t be surprised that intake is up as well. But it seems like maybe more than that is going on. I have noted that farms with strong intake are mixed between already feeding new-crop 2023 silages and still feeding 2022. So, it is not a particular growing season’s crop phenomenon. We are working with higher roughage levels, trying to perhaps increase the length at the bunk, and verifying everything via the Penn State Particle Separator. Raising uNDF240 levels is also perhaps having some success. I wish we could weigh more cows and see if perhaps part of this intake is supporting better fall body condition gains. In some areas, this past summer was particularly hot; perhaps the cows had more weight to put back on as the weather got cooler.
So for now, I am very thankful that the cows are milking well and year over year comparisons are helping everyone have a good Christmas and New Year’s celebration. I agree that we are all riding a wave of genetic improvement not seen before in our industry. There are many positives from this reality, but we need to pay special attention to these cows as they become more and more like fine-tuned athletes. As their caretakers, we must up our game in every part of the dairy to keep up. Onward!