Nutrition and management during both the dry and fresh periods can dictate a cow’s success or failure as she transitions into lactation and ultimately the success or failure of the entire lactation. Therefore, implementation of management practices that focus on optimization of nutrient intake and removal of stressors is critical for transition success. There are many definitions of transition success. However, most of us would probably agree that we want a cow that is healthy, produces a large quantity of milk with good components, and is able to reproduce at the appropriate time. As a consequence of transition success, the dairy is more likely to be profitable and sustainable.
Often there are challenges to achieving transition success. They are usually in the form of nutritional, social, and environmental stressors. A single stressor alone may not impact a cow, but multiple stressors can cause a cow to have an increased risk of health problems. One thing we need to keep in mind is that the best formulated diet during either the dry or fresh period can’t overcome suboptimal management practices. For example, dry cows are often housed in older facilities or facilities that are too small for the cow or herd. Therefore, attention should be given to implementing management practices that allow access to good quality feed while minimizing social and environmental stressors and promoting cow comfort. Well-run dairies have reduced the risk and occurrence of many health problems, such as clinical ketosis, fatty liver, milk fever, displaced abomasum, and mastitis, by feeding diets that better meet the needs of the cow and by improving management deficiencies. However, now some well-run dairies battle with harder to detect health problems like subclinical ketosis, subclinical milk fever (aka hypocalcemia), and subacute ruminal acidosis (aka SARA).
To minimize the risk of those health problems we use integrated nutritional strategies that focus on supporting energy, protein, and mineral metabolism along with rumen function and immune response. There is no “one size fi ts all” dry or fresh diet since different approaches are dictated by the dairy’s management philosophy and ability, feed availability and quality, and facility layout in regards to grouping cows. However, there are some common themes. Diets should be formulated in the context of one another to ensure a smooth change from the dry to lactation periods. For example, the fresh diet is often intermediate in nutrient content and carbohydrate fermentability relative to the dry diet and high (peak) lactation diet. Dry cows should be fed diets that allow them to eat to gut fill and maintain intake before calving. This is where higher forage, lower energy dry diets have been used successfully. By controlling intake, the energy needs (~100-110% of metabolizable energy requirement) of the cows can be met without greatly exceeding requirements. Dry cows that are overfed energy, even those cows with appropriate body condition, deposit more abdominal fat and are predisposed after calving to insulin resistance, increased blood nonesterified fatty acids (NEFA) and beta-hydroxybutyrate (BHB), and greater body weight and condition loss after calving leading to more transition failures.
Dry cows should be fed diets that will supply sufficient metabolizable protein (~85 to 100 g/kg dry matter) to meet their amino acids needs. We don’t want a cow to mobilize protein from muscle and other body reserves until after calving. The fresh diet should promote a rapid rise in intake to control the duration and severity of the negative energy and protein balances that occur. The fresh diet should provide sufficient rumen degradable protein and appropriate fermentable carbohydrates to optimize ruminal fermentation and microbial protein synthesis. In addition, good quality rumen undegradable protein should be used to supply digestible amino acids. Minerals and vitamins play essential roles in many physiological processes so the dry and fresh diets should be formulated to meet the needs of the cow. Dietary cation anion difference (DCAD) can be adjusted as needed during the close-up period or the entire dry period when a 1-group dry diet to minimize the risk of hypocalcemia.
A key question to ask when formulating the diets is “how much TMR are the cows easting?” It’s a simple question yet often difficult to answer especially if it’s not measured. In addition, the dynamic nature of the close-up pen in regards to entries and exits makes it difficult at times to know what cows are actually eating. Dry matter intake is critical for success. A cow should have a consistent intake before calving, avoid a prolonged drop in intake during calving, and have an intake that increases rapidly from calving until peak lactation. Be sure to eliminate as many social and environmental stressors as possible to allow a cow to eat properly and achieve transition success.