Following the current increase in overall production costs, dairymen, nutritionists and feed industry professionals are actively looking for management alternatives to maximize dairy operation efficiency. Since 30 percent of dairy cows in a herd leave the dairy roughly 90 days postpartum, proper nutrition – particularly through the dry and transition period – has a significant impact on the animal’s longevity and performance.

Traditionally we look at the transition period as three weeks prior and three weeks after parturition. During this phase the cow undergoes important physiological, metabolic and social changes.

Nutrition and feed management strategies are key to reduce the incidence of metabolic disorders that negatively impact the success of the subsequent lactation.

Health problems related to the transition period
Adequate nutrition programs and timely, proper diagnoses are important in reducing the incidence of subclinical and clinical upsets. Solid transition programs and employee training can help reduce veterinary treatment costs, improve productivity and ease the risk of problems in early lactation.

• Dry matter intake (DMI) It is well accepted that dairy cows decrease feed intake close to parturition. This is generally attributed to a diminished rumen capacity induced by the rapid growth of the fetus in late gestation, major hormonal changes and body condition score (BCS) at calving.

Research has demonstrated that cows with higher-than-recommended BCS at calving will consume less dry matter and are more prone to develop metabolic upsets as ketosis, displaced abomasums (DAs) and milk fever postpartum.

• Rumen function Rumen microflora, highly represented by fiber-digesting bacteria, have less exposure to rapidly fermentable carbohydrates during the dry period. The rumen papillae decrease in size, reducing the ability to absorb volatile fatty acids (VFAs) and predisposing the cows to rumen acidosis postpartum.

To maximize rumen function and reduce the incidence of acidosis, the rumen ecosystem requires a gradual adaptation. Most feeding programs consider a close-up diet high in starch to promote a gradual microbial population readjustment.

Metabolic problems

• Ketosis and fatty liver
During the transition period, dairy cows consume less energy than what is required for the last days of gestation, maintenance and early lactation. The biological response favors the mobilization of fat reserves synthesized by the liver producing glucose or shunted to produce ketones if the system gets overloaded. As blood concentration of ketones reach 20 to 30 milliliter per deciliter, the animal gets ketotic and milk production is compromised.

If fat mobilization is elevated, liver accumulation takes place, reducing glucogenesis and compromising the availability of energy to the animal.

• Milk fever
Maintenance of blood calcium at calving is a challenge. Colostrum contains up to 10 times more calcium (Ca) than cows’ blood at calving and there is a subsequent drainage of this mineral in milk. As Ca plays an important role in muscle contraction, there are more cases of retained placentas and metritis resulting from hypocalcemia.

Recent research indicates that sodium and potassium can be of concern. High-concentration feed ingredients should be avoided when feeding dry/close-up cows.

• Immune system
Following the DMI decrease there is a notable immune system depression around calving. The animal is subjected to a range of stress factors that reduce the anti-inflammatory response and therefore reduce vaccine and treatment efficiency. Selenium and vitamin E status have important roles in the immune system but are usually neglected in the dry period; the incidence of retained placentas, metritis as well as other infectious diseases, such as salmonellosis and mastitis, then have better chances to evolve.

Reducing the incidence of transition problems

• DMI and BCS
BCS should be monitored throughout the transition period. A well-balanced diet should maintain adequate body condition through the dry period and at calving.

Encouraging feed intake, cow comfort and palatable, high-quality diets may help sustain lower feed intake, thus supporting the high demand of nutrients for production in early lactation.

• Grouping Many farms are finding that keeping first-calf heifers in a separate group after calving has shown positive results. Heifers are less aggressive and will be outcompeted by multiparous cows in accessing the feed due to social interactions. This practice also allows for the adjustment of first-calf heifers’ growth requirements.

Feed additives
Propylene glycol and propionate are used by the cow to produce glucose. These additives are available to promote a short supply of energy-reducing fat mobilization and liver deposition in early lactation.

Anionic salts are used in dry cows’ diets to counteract the cation/anion imbalance and promote calcium availability in the blood.

Conclusion
The transition period is, with no doubt, the most critical period of the cow’s production cycle. A preventive philosophy, sensible diagnostic and an effective treatment program are essential to improve performance and longevity on the dairy.

Monitoring BCS during transition, encouraging DMI in early lactation, focusing on proper mineral balance and promoting a strong immune system are key to reduce the risk of metabolic upsets in early lactation.

Using proven feed additives can help support feed efficiency and immune system response. PD

Pedro Caramona
Alltech, Inc.