Dairy Sense: Troubleshooting Low Milk Components

June 2022

Production perspective

Monitoring the milk components of a herd can help identify the health and nutritional status of lactating cows. Milk cooperatives report component tests on every pick-up empowering managers to address problems sooner versus later. Even though component percent can indicate a performance problem, for economic reasons, pounds of components is the key metric to monitor. In Pennsylvania, many herds struggle to obtain greater than 5.50 pounds of components and the ideal goal is greater than 6.0 pounds.  As summer begins with high temperatures and humidity, milk production and components can be negatively affected. This ultimately will impact milk price and milk income for the year.

Typical milkfat and milk protein for Holsteins are greater than 3.7% and 3.0% respectively. For Jerseys, typical milkfat is greater than 4.9% and milk protein greater than 3.8%. A herd milkfat test below 0.3% of breed average can indicate a problem. In the short-term milk production may be normal, but animals could be experiencing subclinical acidosis. The long-term effects can be a decline in milk production along with the onset of laminitis and other health problems. Milk protein is not as sensitive to nutritional or other external factors compared to milkfat. It is not unusual to observe milk proteins between 2.7-2.9% during the summer, which can reflect cows not receiving enough energy.

Energy intake is a major nutrient influencing both milk volume and components. Ideally, milk production should be converted to an energy corrected basis. The equation used by the Extension dairy team is (12.82 * fat lbs.) + (7.13 * protein lbs.) + (0.323 * milk lbs.). This is an important metric to utilize when examining herd performance.  Energy corrected milk should be used when calculating dry matter intake efficiency. The expected range in dry matter intake for cows averaging between 75 and 85 pounds of milk is 45 to 55 pounds. Feed efficiency between 1.45 and 1.70 is ideal and when greater than 1.70 may result in animals not receiving adequate pounds of fiber or other nutrients.

Dairy cows need a minimum amount of forage and fiber to maintain normal rumen function. Some common guidelines are a minimum forage amount at 1.40% of body weight or no less than 40-45% forage in the total ration dry matter. Low forage and fiber intake coupled with very fine ration particle size can lead to poor production and health. Also, if the ration is coarse and sorting is occurring, this can be problematic as well. Starch levels around 30% of the ration dry matter and where starch is rapidly digestible, such as high moisture corn, can amplify poor animal performance (e.g., subclinical acidosis or reduced milk fat). Dietary fat levels and their source can adversely impact components and should not be overlooked as a possible cause.

Improper feeding management practices can be as detrimental as poor nutrition. Regardless of the type of feeding system, the ration should be available at least 21 hours per day with a minimum of four ration push-ups daily. Feed refusals should be cleaned out daily, especially during the summer to avoid moldy or spoiled feed. In free-stall housing, three linear inches per cow should be available for water. Ideal bunk space measurements are 24 inches/lactating cow with 18 inches minimum and prefresh cows need 30 inches minimum. In conventional feeding systems, hay or some forage should be fed before grain is offered. Grains and supplements should be fed multiple times throughout the day to avoid slug feeding. Frequent feedings help mimic a TMR type feeding system by avoiding large drops in rumen pH, which can result in milk fat depression and other health-related problems.

Currently, the Class III milk price is holding steady around $24/cwt through the end of the year. There is a lot of potential to generate substantial income to help counter rising inflation. Heat stress is one of the greatest bottlenecks to achieving the annual milk production and income needed to cash flow on many dairies. It can take milk cows several weeks to months to rebound from the insult of high temperatures and humidity. Addressing nutritional and feeding management strategies to avoid reductions in milk volume and components will result in a positive return on investment.

Economic perspective

Monitoring must include an economic component to determine if a management strategy is working or not. For the lactating cows, income over feed cost is a good way to check that feed costs are in line for the level of milk production. Starting with July 2014's milk price, income over feed cost was calculated using average intake and production for the last six years from the Penn State dairy herd. The ration contained 63% forage consisting of corn silage, haylage, and hay. The concentrate portion included corn grain, candy meal, sugar, canola meal, roasted soybeans, Optigen®, and a mineral vitamin mix. All market prices were used.

Also included are the feed costs for dry cows, springing heifers, pregnant heifers, and growing heifers. The rations reflect what has been fed to these animal groups at the Penn State dairy herd. All market prices were used.

Income over feed cost using standardized rations and production data from the Penn State dairy herd.

Note: May's Penn State milk price: $27.67/cwt; feed cost/cow: $7.66; average milk production: 84 lbs.

Feed cost/non-lactating animal/day.