Ration changes occur for a variety of reasons on a commercial dairy.

Here are some items to watch and evaluate after a ration change has been made.

Watch for changes in production and milk composition
Milk sales comprise the largest source of income on a dairy. Ration changes can impact average milk yield/cow, peak production, production persistency and milk composition. Tracking changes in these measures is critical for evaluating impact on herd performance and profitability.

Watch for changes in feed intake and feed refusals
Are cows eating the amount of feed specified on the ration sheet? If consumption is higher, then you will frequently be feeding to an empty feedbunk and more cows than normal will come up to eat after providing fresh feed. If consumption is less, excessive amounts of feed will remain in the bunk and the amount offered should be reduced.

Watch for changes in feed refusal consistency
Ideally, feed refusals should look very similar to the original TMR with identical percentages of silages, hay and concentrates. Have the feed refusals changed? In particular, watch for more long hay stems and forage. Increased feed sorting by the cows is indicated if the feed refusals contain more hay stems or silage.

Watch for changes in manure color, consistency or content
Color: Normal manure colors are: brown-olive color on a hay diet and yellow-olive for cows fed TMR diets high in grain. Abnormal manure colors include: gray, dark brown, light green or yellowish color combined with watery diarrhea.

Consistency: The consistency of manure varies due to water content and is influenced by feed moisture content, time feed remains in the digestive tract and health of the animal. Normal manure has a medium porridge-like consistency and forms a dome-shaped pile that is 1 to 2 inches high. Abnormal feces are either too dry (pasty or form balls of manure) or too loose (thin manure, splatters on the concrete).

Content: Ideally fecal samples should indicate uniform digestion and utilization of feeds offered to the animal. Watch for changes in fecal composition such as an increase in the amount of grain or long forage particles, mucus and foam in the manure. An increase in grain particles may indicate poor rumen fermentation, improper grain processing, or excessive grain intakes. An increase in long forage particles may indicate poor rumen fermentation, inadequate cud chewing (rumination) and accelerated rate of passage through the cow. Excessive amounts of mucus or mucin casts in the manure indicate chronic inflammation or injury to lower digestive tract. Manure that appears foamy or bubbly may indicate lactic acidosis or excessive hind gut fermentation, resulting in gas production.

Watch for changes in body condition score over time
Body condition scoring is a method of evaluating fatness or thinness in cows according to a five-point scale and then using the score to fine-tune dairy herd nutrition and health. Research and field experiments have shown that body condition influences productivity, reproduction, health and longevity.

Thinness or fatness can be a clue to underlying nutritional deficiencies, health problems or improper herd management. If done on a regular basis, body condition scoring can be used to troubleshoot problems and improve the health and productivity of the dairy herd. Ration changes may alter body condition scores over time. Are your fresh cows losing too much condition? Are your late-lactation cows too thin or too heavy? EL

By Richard J Norell and Mireille Chahine; Extension Dairy Specialists, University of Idaho