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• It is difficult to achieve adequate levels of immunoglobulins in the calf's serum by feeding low quality colostrum (low immunoglobulins).
• Supplementation of low quality colostrum with dried colostrum does not further increase serum immunoglobulin concentrations in calves.
• Feeding high quality colostrum (high immunoglobulin) results in higher serum immunoglobulin in calves than feeding the same amount of low quality colostrum.

INTRODUCTION

The requirement for colostral immunoglobulins by the newborn calf is well known, as are the principles of passive transfer of immunity from cow to calf. Calves are born with no or extremely low blood immunoglobulin concentrations. Unless they ingest large amounts of immunoglobulin during the initial hours after birth, mortality and morbidity are high. Rate of immunoglobulin absorption by the calf intestine begins declining shortly after birth and the intestinal lining is closed to further immunoglobulin absorption into the blood by about 24 hours after birth. This process of declining rate of immunoglobulin absorption in the calf's intestine is referred to as closure.

Immunoglobulin the calf's blood must reach 10 milligrams per milliliter (10 mg/ml) or greater to provide minimal protection. To achieve this, calves must receive 100 to 300 grams of immunoglobulin within the first 12 hours after birth. Accounting for variability in colostral immunoglobulin concentrations and current newborn calf feeding practices, over 40 percent of U.S. dairy calves are below the 10 mg/ml level of immunoglobulin and are at risk before they reach one day of age.

Problems in achieving adequate passive transfer of immunity can lie in the quality (immunoglobulin concentration) of colostrum fed, the quantity of colostrum fed, and the time of colostrum feedings after birth. Several experiments were conducted to more fully evaluate the importance of these factors and to determine if colostrum of marginal quality could be used to provide adequate calf serum immunoglobulin concentrations after feeding. In each experiment, Holstein bull calves were removed from the dam before suckling and fed the initial colostrum meal prior to 3 hours after birth. Colostrums used in the various experiments were pooled from several cows to provide low quality colostrum (pooled from second and third milkings; typically in the yellow or marginal range on a colostrometer) or high quality colostrum (pooled from first milking). After extensive mixing, pooled colostrums were frozen in one liter portions in zip-lock bags. Bags were frozen flat and then stacked and stored in the freezer. With careful handling to avoid breaking the bags, these colostrum bags could be rapidly thawed in warm water. Calves were fed by nipple bottle and unconsumed colostrum was administered by esophageal feeder. After completion of the colostrum feedings, the calves were fed whole milk twice daily at 10 percent of body weight per day. Venous blood was collected from all calves at 24 and 48 hours after the initial feeding of colostrum. Serum immunoglobulin G1 was determined by radial immunodiffusion assay.

EXPERIMENT 1

In the first experiment the relative importance of quantity and frequency of colostrum feeding was determined using low quality colostrum. Pooled colostrum from second and third milkings of postpartum cows (immunoglobulin G1 concentration was 23.9 grams/liter) was fed to calves assigned to one of three groups. Group I (control) calves were fed 2 liters (one liter = 1.06 quarts) at 0 and 12 hours after birth (95.8 grams immunoglobulin G1 in 12 hours); Group II calves were fed 4 liters at 0 hours and 2 liters at 12 hours (143.7 grams immunoglobulin G1 in 12 hours); and Group III calves were fed 2 liters each at 0, 6 and 12 hours (143.7 grams immunoglobulin G1 in 12 hours). Results (Table 1) indicated that there were no significant differences in serum immunoglobulin G1 concentrations between calves in Groups I and II or between Groups I and III. In contrast, calves fed 2 liters of low quality colostrum at 0, 6 and 12 hours (Group III) had marginally, but significantly, higher serum immunoglobulin G1 than control calves (Group I) at 24 and 48 hours.

EXPERIMENT 2

The second experiment was designed to evaluate the supplementation of low quality colostrum with a dried colostrum product. Pooled colostrum from second and third milkings of postpartum cows (low quality colostrum, immunoglobulin G1 concentration was 25.7 grams/liter) was fed to calves assigned to one of three groups. Calves in all treatments received 2 liters of pooled colostrum at 0 and 12 hours. Group I (control) calves received pooled colostrum only (102.8 grams immunoglobulin G1 in 12 hours). A dried colostrum supplement containing approximately 180 milligrams of immunoglobulin G1 per gram of solid (provided by Milk Specialties Co., Dundee, IL) was mixed with the pooled low quality colostrum and fed to Groups II and III. Group II calves received 136 grams of dried colostrum product at each of the 0 and 12 hours feeding (total of 142.4 grams immunoglobulin G1 in 12 hours) and Group III calves received 272 grams of dried colostrum at each feeding (total of 185.2 grams immunoglobulin G1 in 12 hours). In no case did the addition of dried colostrum to low quality colostrum result in increased serum immunoglobulin G1 concentrations compared with controls (Table 2). No significant difference was found between any of the treament groups.

EXPERIMENT 3

The third experiment was designed to evaluate the role of colostrum quality in absorption of immunoglobulins by the newborn calf. Group I calves were fed 2 liters of low quality colostrum (32.9 grams immunoglobulin G1 per liter) at 0 and 12 hours after birth (131.6 grams immunoglobulin G1 in 12 hours). Groups II and III were fed high quality colostrum (60.1 grams immunoglobulin G1 per liter), with Group II calves receiving 2 liters each at 0 and 12 hours (240.0 grams immunoglobulin G1 in 12 hours) and Group III calves receiving 4 liters at 0 hours and 2 liters at 12 hours (360.6 grams of immunoglobulin G1 in 12 hours). When equal volumes of low and high quality colostrum were fed at 0 and 12 hours, calves fed high quality colostrum (group II) had higher serum immunoglobulin G1 (Table 3) than calves fed the low quality colostrum (Group I). Doubling the amount of high quality colostrum at 0 hours to 4 liters (Group III) resulted in higher serum immunoglobulin G1 concentrations than in either Group I or Group II calves.

CONCLUSIONS

These results have confirmed the importance of feeding sufficient quantities of high quality colostrum within the first 12 hours after birth of the calf. Feeding 4 liters of a high quality colostrum at 0 hours did result in higher serum immunoglobulin G1 concentrations than feeding 2 liters (Table 3). However, a similar comparison when feeding low quality colostrum did not result in a significant difference (Table 1). When low quality colostrum was fed, a more frequent feeding during the initial 12 hours did result in slightly higher serum immunoglobulin G1 concentrations (Table 1). Addition of dried colostrum to low quality colostrum did not increase immunoglobulin G1 absorption, even though the supplement provided a relatively large amount of immunoglobulin G1 (Table 2). Achievement of adequate serum concentrations of immunoglobulin G1 in calves is not difficult if high quality colostrum is available. However, when low quality colostrum must be fed, increasing the volume or adding dried colostrum still does not seem to provide for adequate immunoglobulin absorption. Additional meals may be beneficial, but unlikely to fit into most management schemes. Since the yield of first milking colostrum is inversely related to its immunoglobulin concentration, and since dairy cows are continuously bred for higher milk production, other approaches to optimize immunoglobulin transport in calves fed low quality colostrum should be identified.

TABLE 1. Effects of amount and frequency of feeding low quality colostrum (Exp. 1).

*Mean " standard error. At both 24 hr and 48 hr, Group III means were significantly different from Group I.

Group II was not different from Group I or Group III means.

#Liters of colostrum.

TABLE 2. Effects of supplementing with dried colostrum (Exp. 2).

*Mean " standard error. No significant differences between treatments at 24 or 48 hr.

^#Liters of colostrum.

^?Grams of dried colostrum per feeding.

TABLE 3. Effects of high and low quality colostrum and level of feeding (Exp. 3).

^*Mean " standard error. At both 24 hr and 48 hr, the mean for each treatment group was significantly different from the mean of each of the other groups.

^#Liters of colostrum.