Cowcentric cow management

Bruce Woodacre, Bruce Woodacre Knowledge Management

Imagine a dairy cow that gave 15,000 liters (33,000 pounds) of high-quality milk year after year after year at a high level of efficiency, a cow whose milk had health benefits for the consumer, a cow that got in calf when you wanted her to; a cow that was highly resistant to infections such as mastitis and whose milk had a consistently low somatic cell count, a cow that never suffered from acidosis and a cow that was never lame. Now imagine a herd of such cows, and imagine how profitable it would be.

The reality is, unfortunately, somewhat different. In the United Kingdom over the last 10 years, the average yield of Holstein cows has increased by nearly 20 percent, but this has been associated with a 9 percent fall in butterfat percentage, a 27 percent reduction in conception rates, an increase in mastitis and general health problems and the loss of nearly one lactation in longevity.

Some veterinary surgeons believe nearly all early lactation cows in the U.K. suffer from sub-clinical acidosis. Why is this? Some people like to see a causal relationship between these issues (i.e., “High yields cause disease,” “High-yielding cows are infertile,” etc.), but that is to confuse a correlation with a cause. I accept that there is a strong correlation between high yields and the issues listed above, but I don’t believe the high yields are the cause of the problems.

The science of genetics might hold some of the answers, and breeders in some areas are now selecting for disease resistance and longevity. The science of nutrition might be equally helpful, redefining trace mineral nutrition or examining ways of maintaining rumen stability, and we certainly need to re-examine management strategies to deal with the modern high-yielding cow. None of these, however, will provide the solution on their own. A holistic reappraisal of the problem is required – re-imagining the dairy cow.

The problem is that because we have not followed a holistic approach, developments in the different areas have not kept pace with each other.

Management has certainly not kept up with genetics. Essentially, we have bred racehorses but persist with management techniques more appropriate to a pony. It is a bit like breeding a horse and training it for flat races and then entering it for the Grand National and wondering why it falls at the first fence!

We need to address a number of problem areas:

•The obsession with yield as the goal rather than profitability, in breeding as well as feeding

•Using margin over feed as a target rather than net profit

•The dependence on “ration formulation programs” that are really nutritional models dealing with one cow assumed to have fixed “requirements,” rather than the reality of having a group of cows that “respond” to how we feed them

•Forgetting the cow is a ruminant

•A focus on energy density rather than dry matter intake (DMI)

•Reliance on out-of-date mineral allowances rather than absorbed requirements

•Management systems that have been developed for the convenience of human beings at the expense of cows

You might be able to add to this list. In fact, each of these points is a subject for an [article] on its own, but the point, however, is that we need to deal with these issues in a coordinated fashion. We need to take a holistic approach, and in order to do this we need a framework, something to hang it all on.

A good starting point is a paradigm shift in the way we view the cow “year.” Figure 1 shows the conventional “textbook” view. It does at least recognize that the cow’s year is cyclical and implies problems occurring at one time may well have their causes earlier in the cycle.

Another way of looking at this is, “If you mistreat a cow now, she will probably make you pay for it later on.” For example, the cause of poor breeding performance 60 to 80 days into the lactation is often related to incorrect feeding and management during the dry period.

The main problems with this conventional view are firstly that the cycle is presumed to be one of 365 days and secondly that periods of 100 days have got nothing to do with the cow. We have to start looking at the cow cycle from the cows’ point of view. If we want high genetic merit cows to perform to their potential, to deliver the full economic benefits of their “improved” breeding, we have to change our management of the cycle to work with the cow, not to arbitrary divisions to suit our convenience.

Clearly, any management system has to be practical; we always have to compromise to fit the ideal for one cow to a herd and to the buildings available. Most of what I am proposing could be applied on most commercial farms – it is really an approach rather than a system; it’s an attitude of mind, trying to understand what a cow wants to achieve and helping her achieve it, rather than forcing her to fit outdated systems.

The first issue I have with the traditional cycle is “Why are we fixated on 365 days?” Why is a calving interval of this length perceived as a “good thing”? This, I believe, goes back to when we had cows that followed a classic lactation curve, dwindling to very low yields (or drying themselves off) at 300 days. Any extension of the calving interval of these cows meant extending the days dry and cost a lot in terms of lost annual yield.

The modern Holstein has a flatter, more persistent lactation. At 300 days she may still be yielding 30 liters (66 pounds) or more. Why do we dry cows off giving this much milk (leaving aside that this could be perceived as a welfare issue)?

I am not arguing for extending the lactation to 18 months (the benefits of this have not been proven) but merely that we should take the emphasis away from calving interval as an objective and certainly as an indicator of the “fertility” of a herd. This allows us to delay the onset of breeding until the cow has moved out of the extremes of negative energy balance exhibited by high-yielding Holsteins into a period when we are more likely to be successful.

If the calving interval slips to 400 to 420 days, I am quite relaxed as long as the “days dry” doesn’t increase.

Figure 2 shows the second limitation of the traditional cycle. Cows are “in early lactation” for 100 days, then we change their feeding rate and move them into the mid- lactation group. Unfortunately, the cow herself doesn’t realize that she is supposed to have changed at 100 days post-calving.

For a cow to calve at 365 days, she would have to be inseminated successfully at 80 days. Embryo implantation usually occurs 20 to 50 days after this, and its success will be markedly reduced by stress, nutrition or management. Yet this particularly sensitive period for the cow coincides with the time when the traditional cycle would have us change her feeding and management.

I suggest we replace the term “early lactation” with “conception management” because, in the natural course of events, once the cow has completed the transition from pregnancy to lactation, conception will be her primary objective. This period should last for at least 130 days or, in practice, until a successful pregnancy diagnosis and will coincide more nearly with the hormonal status of the cow.

I used the word “transition” instead of calving advisedly. The visible act of calving we tend to focus on is merely an uncomfortable event in a process that encompasses the period two to three weeks either side of that event. Transition is a critical period and some farmers are now managing these cows separately. This is not always practicable, but we can take steps to make it as successful as possible.

I will return to the impact of the transition period on conception, but for the moment, I want to concentrate on management during the conception period itself. The energy status of the cow during this period is known to be critical, but this has led in many cases, to an overemphasis on the energy density of the diet at the expense of rumen function and, hence, DMI.

The only way I know to increase the energy density of a diet is to increase the starch or fat content at the expense of the fiber. There always comes a point where the balance of the diet is upset and rumen function starts to become impaired. The typical pattern is demonstrated in Figure 3.

This is where we have to remember a cow is a ruminant. The best results are achieved by formulating the diet to achieve optimum rumen function, using positive rumen modifiers and focusing on removing the practical obstacles to DMI to achieve the best energy status of the cow. Such obstacles include water intake and feed presentation, palatability and management.

Management for intake, however, is highly dependent on the last part of the previous cycle. We need to dry cows off at the optimum condition score for calving (3.0 to 3.5) because we shouldn’t try to change condition when they are dry. Gaining condition during this period means “overfeeding” cows and will simply result in any extra feed being partitioned to the calf or the udder. “Underfeeding” to lose condition is equally stupid during this critical period. In any case, as you will see, we have more important objectives during this period.

This means checking the condition score 100 days before drying off so we can manage body condition during this last period of the lactation; this is the next paradigm shift. Rather than using the term “late lactation,” which implies “unimportant” and seems to mean that we can take our eyes off the ball, I would prefer the term “body reserve management” which suggests we have something positive to do during this period. It is not enough just to focus on condition score; it is also important to manage protein and mineral reserves.

Which leaves us with the “dry period.” I want to change this term as well because it is all too often an area of management neglect. Dry cows are all too often put to one side and ignored until just before calving, and yet if we want to achieve high-energy status post-calving through high intakes, this is the time we should be preparing the rumen for a rapid response to the lactation diet.

There are two stages to this. The first is physical preparation. At the point of calving, a cow contains a 45-plus-kilogram (100-plus-pound) calf, plus the placenta and fluids. This means a lot less space for the rumen and, unless we take positive action, it will become compressed and flabby.

At calving, there is suddenly space again, and to avoid displaced abomasa and to ensure a rapid rise in intake, the rumen must immediately fill that space and be ready to go. The way to achieve this is to keep the rumen working; keep it full and active with diets based on straw or a similar low digestibility, high-fiber forage, chopped to no shorter than 5 centimeters (2 inches). The rest of the diet can be made up with whatever feeds are available, as long as the total ration is balanced correctly for all nutrients including the minerals and vitamins.

The last part of the cycle, the pre-calving transition or “close-up” period, involves training the rumen microbes for the task ahead. The population of microbes in the rumen takes 12 to 14 days to adjust to major changes, so we should introduce a controlled amount of the lactation ration into our straw-based diet for these last two to three weeks.

During this period, particular attention should be paid to maintaining the immune status of the cow. Trace elements should be correctly balanced throughout the cycle, but the form and availability are especially important during this critical time. The management of the cow pre-calving can make a difference of +/-3.5 kg (+7.7 pounds) DMI immediately post-calving. Done correctly, intakes and energy status will surge and you will have a solid foundation for the stresses ahead.

There is a case to be made for treating the first two to three weeks of lactation as an early lactation “transition group” – as in calving cows into a separate loose-housed area and allowing them to recover – but this might be considered too complex for many situations.

Figure 4 shows the proposed new way of looking at the cow cycle. It’s a way which considers the cow from the cow’s point of view, or a way which indicates we need to take a holistic view of the cow and consider her needs all of the time. It’s a way which, I believe, provides a framework for re-imagining the dairy cow as described in my opening paragraph. PD

—From 2007 Professional Dairy Producers of Wisconsin Conference Proceedings