Over the last decade, we have heard the phrase “from grass to glass” within our industry. It conveys a variety of messages.
Sometimes it refers to the commitment of quality and transparency throughout the entire dairy process, beginning with nutrients entering the soil and cow, along with the cow’s ongoing management and husbandry. Ultimately, it results in the delivery of safe, nutritious food on the store shelves.
Others will use this term to reflect a production system that utilizes intensively managed grass-based nutritional practices to deliver their dairy products to global markets. Those with a food science background may use “grass-fed” dairy to differentiate dairy product composition changes, which may differ from conventionally fed cows. We are continuing to see product developments that address the health attributes of dairy and niche product markets.
In this article, I would like to explore the merits and risks associated with “higher than typical” forage diets, specifically for lactating cows. I have been ruminating on my observations, especially over the last two years, in clinical dairy practice. In no way, shape, or form am I providing recommendations for your farm. These are just my thoughts and observations to ponder.
We are feeding differently
Forty years ago, I was employed (with many other ag students) at Michigan State University’s (MSU) Dairy Teaching and Research Center. I enjoyed feeding the herd and discussing the “whys” with professors and grad students as it related to the nutritional requirements of my favorite critter, the dairy cow.
At that time, total mixed ration (TMR) feeding was rapidly becoming the “gold standard” practice to provide the perfect mix — each mouthful the same — to standardize nutrient delivery to the cow. The MSU herd was housed in tie stalls and was fed according to production.
As I recall, at that time, we formulated three lactating diets with forage to concentrate ratios of 60:40, 70:30, and 80:20. Obviously, the 60% forage diet on a dry matter (DM) basis was fed to higher production animals. The 80:20 was fed to the lower yielding cows. I cannot remember the exact production levels at that time, but the university herd was considered a high-yielding one.
Current nutritional programs rely heavily on corn silage-based (50:50 or 60:40) rations, fed as one group TMRs for nearly the entire lactation. In Michigan, with plenty of high-yielding herds, a TMR with two-thirds corn silage and one-third alfalfa haylage, plus or minus some fibrous by-product (wet beet pulp, wheat midds, soy hulls, and so forth), is very common — and for good reason. These “tried and true” diet formulations are relatively cost conscious, highly fermentable, and yield a nice quantity of milk.
Risk factors might include TMR sorting, over conditioning (especially with longer lactations), and subsequent transition disease (metritis, ketosis, and displaced abomasum, for example). Body condition score (BCS) changes from dry-off through three weeks fresh often are excessive, greater than 1 unit BCS. Certainly, excellent husbandry, along with precision feeding programs, allow many farms to excel. Herd TMR intakes greater than 60 to 64 pounds dry matter, supporting 6-plus pounds of fat and protein yield, are currently being achieved by high-yielding herds.
Higher forage options exist
Hopefully by now, many of you are thinking through your experience with the cows on your farm. We all remember the years of great forage quality (lower tonnage yield) and poor forage “milkability” (lots of tons, but not delivering in the bulk tank). Consistently procuring the highest dairy quality forage is tough! It is dependent on many variables outside of our control.
We have all seen examples of great dairy farms that excel in providing excellent, highly digestible forage to their milking herd. Typically, the nutritional formulation can take advantage of the quality and reduce the amount of concentrates fed. It is a win-win situation. Dairy cows, as we willingly acknowledge, are herbivores.
Our cows readily adapt to increasing concentrates in a positive, tangible way (milk yield); nevertheless, they are ruminants. Many of us have seen firsthand the consequences of a lactating diet a bit too “hot,” perhaps crossing the threshold of excessive starch or minimal fiber requirements.
Subacute rumen acidosis (SARA) continues to be a risk factor of highly fermentable diets. In many instances, the cows themselves do damage to a well-thought-out ration! Meal size, eating speed, and sorting for concentrates all wreak havoc with a stable rumen ecosystem.
Two years ago, a client of mine decided to “take the plunge” into a high-forage program. His team has historically been successful in the procurement of high-quality forage. This is paramount for success. Every dairy farmer realizes you cannot play “catch-up” with poor roughages.
I agreed to be active in my observations of the large herd and stuck my feet in the water, albeit one toe at a time! Initially, several hundred cows were fed the ration for the first year. We have recently completed the second year on the entire herd.
My initial concerns were related to excessive body condition loss (previously good), plus overall condition. I fretted in my thoughts about fresh cow events and subsequent reproduction performance. We all acknowledged that milk yield would decline and that fiber fill would limit intake. The dairy utilizes herd software, including activity monitoring, health/rumen parameters, and custom A.I. service. We routinely studied herd metrics provided by Dairy Herd Information Association (DHIA) and PC Dart.
Many thoughts to ponder
Lessons learned by this veterinarian include:
- Cows can successfully lose excess weight. BCS has lowered approximately 1 point across the herd. Most cows currently go dry at a score of 2.75 to 3; previously, it was 3.75 to 4.
- Fresh cows are very healthy. Rumens are full, there is a lot of cud chewing, very little ketosis, and virtually no displaced abomasums.
- Reproduction is the same as before, at 46% conception rate and a pregnancy rate in the mid to upper 20% range over the last 12 months.
- Death loss and culling rate are about half of the national DHIA average. This was the case prior to our current nutritional program as well.
- TMRs are wetter (35% to 40% dry matter), so that’s not a problem, and there’s not much sorting.
- The lactation curves are much different, obviously with lower peaks from very low starch diets.
I have many more questions to ponder, but not enough space here to get started . . . maybe next time. Remember, the dairy cow gives us a lot of choices. We all don’t drive Fords, and we all don’t milk Holsteins, but we all strive to be the best shepherds of our herds, our families, and our farms. Let’s keep our minds sharp and our eyes open, looking for ways we can further ensure quality soils, quality feed, and quality health for our herds.