The intestinal health of calves can be improved with feed additives in the class called “adsorbents,” according to Michael Ballou, Professor and Chair in the Department of Veterinary Sciences at Texas Tech University. What’s more, healthier intestines can lead to healthier production and profits in the long term.
Ballou shared his thoughts on a broad range of calf health and nutrition topics on a recent webinar hosted by the Dairy Cattle Reproduction Council, “Early life calf health and performance have long-term impacts on lifetime health and (re)production performance.”
He said keeping calves growing and productive depends on a triad of fundamentals – nutrition, environment, and disease control – with each of the three having relatively equal importance.
He noted industry data indicating that the incidence of scours in the preweaning phase can set calves back about 67 grams per day in average daily gain (ADG). That ADG loss is important because it can translate into lifelong performance.
One study showed that heifer calves yielded additional lifetime milk production of 321-569 pounds for every .25-pound increase in ADG. Another showed that heifers with low preweaning ADG were 3.4 times more likely to be removed from the herd before first calving, compared to better-gaining herd mates.
Intestinal health can be enhanced with a wide range of supplements added to milk replacer and/or calf starter. They include extended feeding of colostrum; bovine serum/plasma proteins; yeast cell walls (including cell-wall extract and MOS and beta-glucan fractions); live yeasts; direct-fed microbials; butyric acid; and hyper-immunized egg proteins.
Adsorbents fall into this category as well, and act to protect intestinal health by binding bacterial toxins and preventing them from causing intestinal tissue damage and/or inflammation. In other words, bacteria are still present, but their deleterious effects are minimized because the adsorbent blunts the effects of them before they can cause damage.
Recently, Ballou and his team evaluated an adsorbent by directly injecting challenge bacteria into calf intestinal tissue, with and without the accompanying adsorbent, and alongside a control of sterile saline only.
The introduction of Salmonella typhimirium caused significant damage to the length of villi in the ileum (lower portion of the intestine). Such damage can interfere with digestive absorption, but was negated when the adsorbent was injected with the disease challenge.
An introduction of E. coli endotoxin caused a spike in neutrophil count in calf intestinal tissue. Neutrophils are recruited to fight infections (another example is somatic cells in mammary infections) and cause a great deal of inflammation. The addition of the adsorbent minimized neutrophil counts to nearly equal that of the control treatment.
Ballou also shared another data set from an ongoing study in which preweaned calves were directly challenged with an enteric infection. Half were left untreated, while the other half received a “kitchen sink” of preventative tools in a treatment that included a blend of plasma, yeast cell walls, direct-fed microbials, adsorbents, vitamins, and trace minerals.
The results were fairly stunning, in that nearly 50% of the untreated control calves had died by 21 days into the study, while only 12% of the treated calves died. Among all of the surviving calves, the treated calves also gained an average of an additional 16 pounds per head when weaned at 56 days.
All of the calves in both groups incurred clinical scours. “Our treatment did not prevent scours, but it allowed most of the treated calves to recover,” stated Ballou. “This shows there are technologies and additives we can use to improve the intestinal health of calves.”
