When I first started my veterinary practice in the early 1980s, dry cow management was essentially “management through neglect” as we did not view the non-lactating cow as a major cog in the wheel of farm income. The focus has always been on how the dairy cow diet can be manipulated to produce milk more efficiently and economically.
Since then, much research on dry feeding and management has opened our eyes to the crucial importance of the once perceived “resting phase” immediately before calving and subsequent lactation.
Hall of Fame basketball coach and player, John Wooden, who is also known for his witty statements, said, “If you don’t prepare, you prepare to fail.” This concept certainly fits our current vision of the dry Cow in relation to the dairy cow’s production cycle. Ignoring the details of dry cow feeding and management will result in failed lactation no matter how much you manipulate and add special supplements to the lactation diet.
Why is the dry cow diet so important? Although the nutrient requirements are not high compared to lactation during the dry period, defined here as the last 40-60 days of gestation, the pregnant cow’s ability to consume enough nutrients to make the metabolic transition into lactation is. Studies show that cows with a marked decrease in dry matter intake in the 2-3 weeks prior to calving are at greater risk for a number of postpartum disease conditions, such as ketosis, displaced abomasum, metritis, and restrained fetuses Membranes. Poor quality feed, limited feed availability or management problems are possible factors causing the decline in feed consumption. Management issues such as overcrowding in dry cow stalls, neglect of heat stress and grouping strategies that lead to frequent stall movements or heifers and mature cows have more of an impact on dry matter intake than feed quality.
The story of Goldilocks and the three bears is a well-known children’s fable. The current approach to helping dry cows meet their energy needs takes its name from this fable, the Goldilocks Diet. Research has shown that dry cows, especially at the beginning of the dry season, use too much energy or put too little energy at a higher risk of failed lactation than cows that use the “just right” amount. Cows that use too much energy in the early dry season are more prone to metabolic disorders associated with ketosis and fatty liver. Insufficient energy intake leads to reduced milk production, loss of body condition and reproductive failure.
The protein content of dry cow feed has been somewhat controversial as the defined requirement suggests that 12% would be more than sufficient; However, heifers are better at consuming a higher crude protein diet (14-15%). Research looking at higher dietary protein for mature dry cows was mixed in results, although milk yield was the main goal compared to health and reproductive performance. Cows lack reserve body protein and mobilize muscle and blood proteins to scavenge the amino acids they need to support fetal development or milk production when food intake is insufficient. Excessive protein mobilization in late pregnancy or early lactation results in low milk protein levels, a higher risk of disease and poor reproduction. Since additional dietary protein cannot be stored in the body for later use, the dry cow should be properly formulated to deliver the critical amount of protein to the largest number of cows in the group. Therefore, protein uptake must be formulated based on the observed variations in dry matter uptake within the group.
The main problem with the dry cow diet is preparation for stable calcium homeostasis after calving. Hypocalcemia, better known as milk fever, is considered to be a significant “gateway” disease of the postpartum period that predisposes the cow to many other disease events. Clinical (Down Milk Fever Cow) and subclinical (Droopy Fresh Cow) hypocalcemia are metabolic problems immediately after calving. The presence of hypocalcemia is greater in older cows and is directly related to the mineral content of the dry cow feed. The main mineral problem in the dry cow feed is the potassium content of the feed. You want to select as little feed as possible (preferably less than 1.2%) to be used as the main feed for the dry cow feed. Next, add magnesium to at least 0.35% to 0.4% dry matter. Make sure the source of magnesium is available. Recent research has not shown calcium levels to play a major role here, although most of us have been taught to do so. I am more concerned about higher phosphorus intake (more than 0.4% dry matter). If your vet is concerned about calcium issues, consider an anionic program. This includes adding a high chloride supplement to “acidify” the cow and help her better maintain calcium homeostasis. Ask your nutritionist about the options.
Finally, the little things need to be taken into account, trace elements and vitamins. These essential nutrients are all important in supporting the immune response and protecting the cow and her developing calf from metabolic oxidative damage by promoting better antioxidant status. Vitamins A and E have been shown to minimize retained fetal membranes and mastitis. You want to make sure the dry cow is consuming enough trace elements that are available to the cow and the vitamins to support her immune response. Adding organic mineral sources to 20-50% of the formulated requirement based on inorganic sources can further boost the cow’s immune response.
As can be seen from this description of the role of the dry cow diet in cow health and performance, one can truly see that an adequate balance of the dry cow diet prepares your cow for SUCCESS in her lactation rather than failure. In today’s challenging dairy environment, we need more cows to successfully transition from gestation to lactation.
Dr. Robert Van Saun is a Penn State Extension veterinarian.
Dr. Robert Van Saun is a Penn State Extension veterinarian.