The best procedure for feeding calves with diarrhea has been a subject of controversy. In particular, it has been debated whether it is beneficial to feed milk during treatment and recovery. Use of oral rehydration solutions electrolyte solutions) is a popular and effective way to treat diarrhea. Milk is usually withheld during oral rehydration therapy, because it is assumed that calves are less able to digest milk during diarrhea. Undigested milk is believed to worsen diarrhea by being fermented by intestinal bacteria and increasing osmotically induced fluid excretion. These ideas probably originated from the rapid drop in fecal output observed when milk is removed from the diet, and may not actually indicate a decreased ability to use milk during diarrhea.

Disadvantages of removing milk from the diet of calves during therapy for diarrhea include loss of body weight, protein-energy malnutrition, and decreased immune function. Furthermore, calves raised in hutches during cold weather require more energy for maintenance. The increased requirement for energy during cold stress, coupled with the increased demand for energy during disease, would not be met by the supply of energy in most oral rehydration solutions. Canadian and Wisconsin researchers allowed calves that were experimentally challenged with pathogens to voluntarily consume their normal allotment of milk in conjunction with an oral rehydration solution. Calves given a full ration of milk and oral rehydration solution gained body weight at a rate comparable to healthy calves, and diarrhea was not worsened. Our experiment was designed to test the therapeutic value of keeping calves on milk while feeding an oral rehydration solution, using calves with naturally occurring diarrhea.

MATERIALS AND METHODS

Forty-two calves (20 female and 13 male Holstein, 4 female Ayrshire, 3 female Jersey, and 2 female Brown Swiss) that were an average of 10 days old when diagnosed with diarrhea during February through August of 1992 were assigned to one of three oral rehydration therapy treatments (Table 1). Assignment to treatments was at the first feeding after a fecal score of greater than two (1 = normal, 5 = watery) was observed. Calves were assigned alternately to treatments so that each treatment had equal numbers of each breed, except that one Ayrshire was utilized in place of one Brown Swiss for treatment C.

Treatments are described in Table 1. The source of milk was non-salable whole milk from cows that had been treated for mastitis; only milk from the last two days of the non-salable period was used. Treatment A represented the traditional protocol for therapy, which consisted of removing milk from the diet during the first two days of therapy and feeding only an oral rehydration solution (Advance Arrest™, Milk Specialties Co., Dundee, IL). For treatment A, the amount of oral rehydration solution fed on days 3 and 4 was decreased to 50 percent of the amount given on days 1 and 2; the amount of milk fed was increased to 5 percent of body weight. On days 5 and 6 the amount of oral rehydration solution fed was decreased to 25 percent of the amount given on days 1 and 2, and the amount of milk was increased to 7.5 percent of body weight. On day 7, a full ration of milk (10 percent of body weight) was offered, and feeding of oral rehydration solution was discontinued.

For treatment B, calves were given oral rehydration solution and milk in amounts of 10 and 2.5 percent of body weight, respectively, on days 1 and 2. On days 3 and 4, the amount of oral rehydration solution was decreased by 25 percent of the amount given on days 1 and 2 and the quantity of milk offered was increased to 5 percent of body weight. On days 5 and 6, oral rehydration solution was decreased by 50 percent of the quantity offered on days 1 and 2, and the amount of milk given was increased to 7.5 percent of BW. On day 7, oral rehydration solution was discontinued and milk feeding at 10 percent of body weight was resumed. For treatment C, a full ration of milk (10 percent of body weight) was offered during the 7 days of therapy; oral rehydration solution was given in amounts of 10 percent of body weight on days 1 and 2, 5 percent of body weight on days 3 and 4, 2.5 percent of body weight on days 5 and 6, and none on day 7.

Treatments A and B were given in two daily feedings at 8 AM and 3 PM and treatment C was given in three daily feedings at 8 AM, 3 PM, and 8 PM. For all treatments, milk was offered first and oral rehydration solution was offered 15 minutes after milk. Any milk not consumed within 15 minutes after it was offered was removed and the amount refused was recorded. Any oral rehydration solution not consumed voluntarily was force-fed by using an esophageal (tube) feeder. All calves had received high-quality colostrum (5 percent of body weight) within 30 minutes after birth and an additional 5 percent of body weight as colostrum within 6 hours after birth. Calves were housed in outdoor hutches and had continuous access to a complete pelleted starter and water.

Fecal score for each calf was recorded at each feeding. Calves were weighed 30 minutes before the first feeding of treatments and again at 30 minutes before feeding on days 3 and 7 of therapy. Rectal temperatures were recorded for each calf during weighing. Fecal cultures were conducted to determine the presence of Salmonella and Escherichia coli, and stains to detect Campylobacter and Cryptosporidium were performed. Blood samples from each calf were collected 30 minutes before the first feeding of treatments and again 30 minutes before feeding on days 3 and 7 of therapy. Packed cell volume of blood and concentrations of electrolytes in serum were measured as indicators of the degree of dehydration and acidosis in the calves.

RESULTS AND DISCUSSION

No calves died during the experiment, and at no time did any calf become unable to stand or to suckle. By day 7 of therapy, all calves appeared to have recovered fully from diarrhea. For treatments A and B, all calves readily consumed their milk and no calves had to be force-fed oral rehydration solution. For treatment C, four calves had to be force-fed oral rehydration solution during day 1 of therapy. Eight of the 14 calves given treatment C refused some of their milk at least once during treatment. Inappetence was more frequent during the first 2 days of therapy than during days 3 to 7. Perhaps calves given treatment C would have consumed more of their milk voluntarily had the treatment been offered in four rather than three feedings daily, or if the three feedings had been spaced equally throughout the day.

A plot of body weight versus day of therapy is shown in Figure 1. Calves given treatment A had an average net loss of over 2 pounds of body weight by day 3 of therapy, but gained body weight during days 3 to 7; overall, calves given treatment A had a net loss of body weight during the 7 days of therapy. Calves fed treatment B had a net loss of about one-half pound of body weight by day 3 of therapy, but replenished lost body weight during days 3 to 7. In contrast, calves given treatment C averaged a net gain of over 1 pound of body weight during days 1 to 3 and continued to gain weight during days 3 to 7 of therapy.

Analysis of serum electrolytes and packed cell volume (data not shown) indicated that for calves given treatment A, loss of body weight probably was attributable to loss of both body fluids and tissue. Breakdown of body fat stores likely occurred because oral rehydration solutions alone do not supply enough energy for maintenance. Calves given treatments B and C evidently were supplemented with adequate total fluid to prevent dehydration. The loss of body weight for calves fed treatment B, therefore, was more likely due to breakdown of body fat.

A plot of fecal score versus day of therapy is shown in Figure 2. Fecal score decreased during therapy for calves given any of the treatments, indicating that calves were recovering from the diarrhea. Treatment effects were not significant, demonstrating that keeping calves on milk during oral rehydration therapy did not worsen or prolong diarrhea. Our findings support observations by other researchers that indicate that the widely implemented practice of removing milk from diarrheic calves during oral rehydration therapy may not be beneficial. Concerns are expressed that diarrhea decreases the ability of the calf to digest lactose in milk, but if this had occurred calves given treatment A should have shown a noticeable increase in fecal score on days 3 and 4 of therapy when milk feeding was resumed. No such increase occurred (Figure 2). It is evident from our data that even during diarrhea, calves have sufficient digestive capacity to utilize milk without worsening diarrhea.

Cryptosporidium was the organism most frequently isolated from feces of calves given any of the three treatments. In some calves, more than one genus of pathogenic organism was isolated and it was difficult to ascertain the organism responsible for causing diarrhea in each calf. Cold-stressed calves infected with Cryptosporidium reportedly are more susceptible to mortality, particularly those calves fed a restricted diet. This suggests that an additional source of energy needs to be supplied to calves infected with Cryptosporidium. Our results indicate that supplemental energy in the form of milk was not detrimental to the health of diarrheic calves and may have promoted recovery.

CONCLUSIONS

Feeding calves milk plus an oral rehydration solution during treatment for diarrhea did not prolong or worsen the disease. Calves were able to utilize milk during diarrhea and gained more weight when fed the normal amount of milk during oral rehydration therapy. Maintaining calves on a full diet of milk plus an amount of oral rehydration solution equal to or greater than the estimated amount of fluid lost in feces would seem to be the method of choice for treating diarrheic calves.

The results and conclusions of our experiment are based on early intervention for diarrheic calves. Even though some calves experienced severe diarrhea, none became excessively dehydrated or developed acidosis. Although we do not know if similar results would have occurred if therapy had begun during the later stages of diarrhea, Wisconsin researchers have reported good success at treating severely ill calves in this same manner. Prompt and dedicated attention to oral rehydration therapy is critical to successful treatment, and every effort should be given to ensure that calves are supplemented with fluid and electrolytes at the earliest onset of diarrhea.

Table 1. Dietary treatments.¹

¹Treatments A and B were given in two equal feedings at 8 AM and 3 PM; treatment C was given in three equal feedings at 8 AM, 3 PM, and 8 PM.

²Whole milk.

³Oral rehydration solution (Advance Arrest, Milk Specialties Co., Dundee, IL).

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