The following answer was provided by Noah Litherland, extension dairy scientist, and Alanna Kmicikewycz, graduate research assistant, at the University of Minnesota.
Q: What are some strategies to enhance starter grain intake in pre-weaned dairy calves?
A: Stimulating starter grain intake early in a calf’s life confers health and growth benefits.
Consuming dry feed, such as starter grain, results in improved rumen functionality both in microbial population and absorptive function. This improved development results in greater capacity for fermentation and improved efficiency of use of volatile fatty acids (VFA’s) that are the end-products of fermentation. The VFA’s, particularly butyrate, stimulate the growth and development of the rumen.
Starter intake tends to steadily increase once the rumen has developed. Additionally, pancreatic secretions, such as pancreatic amylase, which is necessary for starch digestion, increase with increasing starter intake. Rumen development along with increased flow and activity of enzymes in the small intestine result in increased digestion of starter grain, resulting in improvement in the efficiency of calf growth.
Consuming dry feed likely alters the rate of passage in the GI tract, resulting in alterations of fecal consistency. As consumption of dry feed increases, the source of nutrients for the calf begins to change from products absorbed directly from digestion of milk or milk replacer to a combination of dietary ingredients and end-products of microbial fermentation (VFA and microbial protein).
A fully functioning rumen may also serve as an important line of defense against intestinal pathogens that cause calf scours. As a calf matures, increasing starter intake results in improved digestive and metabolic capacity to efficiently use nutrients from starter grain.
Good calf-starter grains are:
- Readily fermentable.
- Optimize microbial growth in the rumen.
- Provide bypass protein and starch to be digested in the small intestine.
Here are our top 12 management strategies to increase starter intake by pre-weaned dairy calves.
- Ensure that calves can easily access high-quality starter grain. Calves that are not tall enough to easily reach into the bottom of starter pails should be fed starter in shallower pans. Provide 1 pound of starter daily by day seven. Calves will start nibbling on starter by 10 days of age, especially during winter.
- Provide adequate clean water. Quigley et al., 2006 showed that water and starter intake is closely linked.
- Increase the amount offered to ensure that calves do not run out of starter. Increases in starter intake may be as much as 0.5 to 1 pound daily as calves reach 42 days of age. Frustrated and hungry calves may play with their buckets more, resulting in spilling of feed and fouling of buckets.
- Consuming starter may be a behavior that is learned earlier on in calves fed in groups vs. individual pens (Kung et al., 1997).
- Calves with failure of passive transfer (inadequate colostum) have impaired health and growth (Godden, 2008). We have noticed that our calves at the University of Minnesota with a total protein of less than 5.5 mg/dL are slower to start consuming starter.
- Step-down milk replacer programs, where the amount of milk replacer offered is decreased at approximately three or four weeks of age, along with early-weaning programs, have resulted in increased starter grain intake (Luchini et al., 1991; Hopkins, 1997; Khan et al., 2007).
- Providing almost all of the calf’s nutrient requirements for maintenance and growth by feeding accelerated milk replacer programs or whole milk can reduce starter intake (Cowles et al., 2006; Hill et al., 2010). We are currently finishing a research project that aims at determining if increasing feeding frequency from twice to four times daily alters starter intake in calves fed a 26:18 milk replacer at 2.5 percent of body weight.
- Interactions of starter intake and feeding long forage have not been fully explored. If calves are bedded on straw and the starter contains rolled oats or another fiber source, then hay is not likely needed. If hay is fed along with starter, then select forage with highly digestible NDF, moderate crude protein, and high in sugar content (Drackley et al., 2008).
- Minimize heat stress in calves (Broucek et al., 2009). Open vents on hutches, provide shade, and ensure that adequate fresh water is available at all times.
- Minimize negative effects of birds, flies, and other pests on starter quality, cleanliness of facilities and calf health.
- Minimize “fines” in calf starter (Bateman et al., 2009).
- Avoid abrupt weaning. Calves weaned over a period of 10 days had higher starter intake than those weaned over four days (Sweeney et al., 2010).