By Adrian A Barragan
As I mentioned in one of my previous articles, the transition period is one of, if not the, most challenging period for dairy cows during their production cycle. During this time, cows experience four main physiological challenges: a drop in dry matter intake, an increase in nutrient demands, immunosuppression, and systemic stress and inflammation (especially around calving). Therefore, the best approach to manage this group of animals is by addressing these challenges. If we think about the drop in intake and the increase in nutrient needs, the main negative effects are animals going into a negative energy balance (because they are using more nutrients than what they are consuming) and developing metabolic diseases such as ketosis and fatty liver. Now, we cannot decrease the nutrient demands that cows have at this time, but we can decrease the drop in dry matter intake through proper management. Although cows will experience some degree of immunosuppression during this time regardless of management, an exacerbated stressful and/or inflammatory response may magnify this immunosuppression, increasing the risk of cows developing diseases. The losses for dairy cows associated with diseases are well known, but on top of affecting the welfare of cows and economics of the farm, these conditions have a long-term effect on the productivity and fertility of cows, decreasing milk production and conception rates, and increasing culling of animals. By modulating stress and inflammation after calving, the risks of developing diseases and poor performance may be decreased.
The management practices for transition cows must be focused on maximizing dry matter intake and modulating stress and inflammation. To maximize dry matter intake, diet composition — especially fiber and energy concentrations —is one of the most critical factors. Dr. Robert Van Saun clearly explained in our previous articles some of the key aspects for formulating transition cow diets. Although diet composition is important, I would argue that what we do with that diet is equally important. We could have the best formulated diet with the best ingredients, but if cows do not have access to it, the diet composition would be irrelevant. During this period, cows should have access to fresh feed at least 23 hours a day, and only have no feed available while cleaning the feed bunk in between feed deliveries. There are two main practices that stimulate cows to go to the feed bunk and eat — feed push-ups and feed delivery frequency. It is recommended to push feed up every two to four hours, with more frequent push-ups (every 30 minutes) during the first two hours after fresh feed is delivered. With regard to feed delivery frequency, research has shown that when performed often, up to four times a day, this practice will stimulate cows to go to the feed bunk and eat. However, feeding cows four times a day can be logistically complex in a farm setting, and the recommendation is to deliver fresh feed at least two times a day, ideally three, for this group of animals.
Now, none of the practices above will work if cows are not offered a spot at the dining table, which leads to an important factor: proper stocking density. Although this is a broad topic, I will try to summarize it in a few sentences. There are two ways to measure stocking density; one of them is based on the lying surface, or stalls, and the other one is based on the feed bunk space. The safest way to assess this, to guarantee feed availability, is to use the feed bunk space method. By measuring the feed bunk space in inches and dividing that by number of cows in the pen, the space at the feed bunk that each cow has access to can be estimated. Ideally, 30 inches of feed bunk space is required per cow in the pen, which will be equivalent to having a stocking density of 80%-85% based on number of stalls in the pen. Other practices that can increase dry matter intake and modulate stress are keeping the number of pen movements at the minimum possible (to decrease the stress associated with the re-establishment of pen social hierarchy) and avoiding commingling first-lactation cows with older cows.