Among the most critical nutritional tools available to today’s modern dairies are those products that enhance rumen function and efficiency. These products, commonly referred to as rumen enhancers, increase the rumen’s efficiency by creating an environment that allows for the more complete digestion of ration feedstuffs. A resulting increase in the absorption of nutrients occurs.

Vitamin D is typically recognized as being necessary for proper bone formation and maintaining calcium and phosphate in the body. Recent discoveries indicate that vitamin D also is required for the activation of critical innate immune defenses of cattle against microbial pathogens.

Mastitis is inflammation of the mammary gland usually caused by a bacterial infection. Poor nutrition does not cause mastitis, but poor nutrition can make it easier for bacteria to become established in the mammary gland, resulting in increased rates of mastitis.

While doing some digging for an undergraduate nutrition course recently, I came across an interesting controversy from the early years of nutrition science. It seems that Louis Pasteur, the renowned scientist who was responsible for identifying microbes as the causative agents of many diseases, dismissed suggestions that some diseases could be caused by nutritional deficiencies.

The world inhabited by rumen microbes, though hidden from view, is fascinating. Dark and devoid of oxygen, the rumen may seem inhospitable to life. In reality, it is quite the opposite: Hundreds of trillions of microbes can be found in a single, 20-gallon rumen of an average cow (Figure 1). By comparison, only 100 billion people have ever lived on earth.

Higher grain prices in recent years have encouraged dairy producers to consider increasing the amount of forage and byproduct ingredients in rations for lactating dairy cows. Because this differs from past traditional diets, a feeding study led by Dr. Kenneth Kalscheur at South Dakota State University was conducted to evaluate milk production with diets with elevated levels of forage and byproducts.

In the previous two articles, feed efficiency (FE) has been defined, and its use as a stand-alone monitoring tool or in conjunction with income over feed costs has been examined. The other opportunity for using FE is evaluating the potential impact on manure volume excretion as well as its nutrients. This could have implications for farms with a limited land base or need to export manure off-farm.

Throughout this article, NDF refers to aNDF, determined with use of amylase and sodium sulfite as described by Mertens and official AOAC methods of fiber analysis. For brevity of the acronyms, the “a” is omitted. Fiber digestibility is a critical factor in dairy nutrition. It is involved in many parameters used to balance rations and evaluate forages. It affects dry matter intake (DMI) and gut fill capacity as well as total chewing time both eating and ruminating, not to mention milk and milk components production.

An important factor in calfhood health is the presence of maternal antibodies in calf serum during the critical first few weeks of life for protection from disease. One study shows that compared to maternal colostrum, feeding a lacteal-derived colostrum replacer provides a more uniform range of antibody titres to some common respiratory viruses affecting calves. Feeding a colostrum replacer may allow for better prediction of vaccination schedules and reduced incidence of disease in a herd.

“We can improve feed efficiency by improving how we feed, breed and manage cows,” says Mike VandeHaar of the department of animal science at Michigan State University. VandeHaar was a presenter at the 4-State Dairy Nutrition and Management Conference held this summer in Dubuque, Iowa.