DESPITE dairy producers' best efforts, sometimes silage will succumb to yeasts, molds and other microbes that cause spoilage.
Including this damaged feed at low rates may be tempting, but even small amounts can disrupt the cow's normal rumen function -- and can lead to reproduction problems or impaired cattle health.
"Disposing of the spoiled silage can feel like throwing money away, but it may be the best solution to avoid further problems," Dr. Bob Charley, forage products manager for Lallemand Animal Nutrition, said. "Molds in feed can cause respiratory problems, reduce intake and negatively impact production. Furthermore, some common spoilage molds may produce mycotoxins under certain circumstances, which can cause serious health issues."
Charley warned that feeding even small quantities of spoiled silage can lead to drops in intake, acidosis-like symptoms and reduced fiber and dry matter digestibility. In dairy herds, reduced milk production and milk fat also are common.
According to Charley, a study by Kansas State University incorporated various levels of spoiled silage into the ration of steers and found that including just 5.4% of badly spoiled silage in the ration reduced dry matter intake by 1.3 lb. per day (Figure).
"Limiting or preferably eliminating spoiled silage is the best bet for maintaining production, herd health and preserving valuable feedstuffs," Charley said. "There's no substitute for the basics of good silage management."
To achieve this goal, he recommends the following:
* Start with good-quality forage, harvesting it at the right stage of maturity and moisture level;
* Set the theoretical length of cut to achieve the right chop length, and check the actual particle size distribution;
* Treat all forages for silage with an inoculant backed by independent research data to ensure that it will achieve a dairy operation's objectives;
* Pack the silage well to make sure air is excluded;
* Cover and seal the silage well immediately, taking care to repair any damage to silage plastic during storage, and
* Manage feedout by removing 6 in. or more from the face, keeping the face straight and clean and avoiding leaving any drop (compost) piles.
"Spoilage yeasts occur naturally in varying numbers on all pre-harvest crops," Charley noted. "If these yeasts become dominant, they can start the process of aerobic deterioration -- raising the forage pH, which allows for further spoilage by molds and bacteria. To win the microbial war in your silages, it's important to use proven forage inoculants containing fast-acting, efficient, homolactic acid bacteria. This loads up your silage with an army of billions of these good microbes and helps ensure that the right balance is in place."
Market dairy cows
Dairy producers need to remember that they also are in the beef business. In fact, according to recent U.S. Department of Agriculture survey data, market or cull dairy cows represent about 6-8% of the beef produced in the U.S. annually.
With that in mind, it's imperative that only healthy dairy cows -- those whose meat is fit for human consumption that have completed all mandated withdrawal times for any drugs administered -- are culled for the beef supply.
"For now and in the foreseeable future, the dairy industry will be providing a significant portion of beef to consumers in the U.S.," Zoetis dairy technical services senior veterinarian Dr. Richard Wallace said. "Healthy food is one of our three tenets of dairy wellness, and we call on dairy producers to employ the same commitment to high-quality meat that they give to producing quality milk."
An important part of marketing quality beef is making sure cows do not have drug residues in their meat when they go to market, he said.
"There are many reasons residue violations occur, but most are because of mistakes made at the farm level," Wallace said. "Not keeping accurate records is a big contributor to violations. For instance, if producers or their employees don't know when a treatment was given, they might ship or milk the treated cow before she should have entered the food supply."
Another leading cause of drug residue violations is when producers use a product for purposes not listed on its Food & Drug Administration-approved label.
Any extra-label drug use should occur only when necessary and under the guidance of a veterinarian, and accurate records of proper withdrawal and withholding times must be kept. Dairy producers should take active steps to ensure that their employees always follow label directions.
"It is important that producers work together with their veterinarian to continue to improve the overall quality of milk and meat products," Wallace said. "Pay attention to label indications, and take extra care to ensure all cows bound for the food supply are healthy. Ultimately, it's a matter of making sure we are producing a safe, quality animal and aren't violating trust from consumers."
Reducing heat stress
Reducing dairy cow stress and maintaining good health is essential to help sustain a consistent and high level of milk yield.
A research study presented at the American Dairy Science Assn./American Society of Animal Science (ASAS) Joint Annual Meeting in Orlando, Fla., demonstrated that an immune system-supporting nutritional supplement (OmniGen-AF) can help protect dairy cows from the effects of heat stress by supporting normal immune function.
The research was presented as poster T25 by Nicole Burdick Sanchez et al. and was selected as a "Presidential Pick" at the meeting by ASAS president Dr. Debra Aaron, a University of Kentucky animal sciences professor.
The objective of the research was to study the differences in response of dairy cows supplemented with the patented product to various hormonal challenges when housed at different temperature-humidity indexes (THIs). Two groups of Holstein cows were housed in temperature-controlled modules with THIs set less than or greater than 72 -- the level at which dairy cows begin to experience the effects of heat stress.
Blood samples and rectal temperatures were monitored during the 10-day study, which was conducted at the University of Arizona-Tucson, in collaboration with the U.S. Department of Agriculture/Agricultural Research Service's Livestock Issues Research Unit in Lubbock, Texas.
Results showed a reduction in stress hormones in the supplemented cows versus the control group. The researchers concluded that supplementing lactating dairy cows with the immune system-supporting product may help prevent the negative effects of heat stress on infection-fighting white blood cells.
This research reinforces results of earlier studies demonstrating the positive impact the product has on dairy cow health and milk production during periods of heat stress.