A Practitioner's Views on Fluid Therapy in Calves

Fluid and Electrolyte Therapy

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A Practitioner's Views on Fluid Therapy in Calves

Aaron M. Tromp, MedVet, Drs·

The need for an effective therapy against dehydration caused by diarrhea is evident in a country with a small but highly productive national dairy herd of 140,000 cows. The genetic potential of each replacement heifer makes her value greater than the cow that she will replace. Since Israel does not produce enough beef to meet its domestic demand, dairy bull calves are raised for 12 months to a weight of 450 - 500 kg. As a dairy practitioner, I consider minimizing calf mortality to be one of my major clinical responsibilities. The relatively high value of both bull and heifer calves to dairies in Israel, as well as the unique veterinary service system, has given me an opportunity to develop and deliver methods of rehydration therapy that may not have been economically justified in other circumstances. However, the experiences and observations that I share in this paper will, I hope, be valuable to others around the world.

THE AREA OF BE'ER-TUVIA In order to give the reader an appreciation of my practice area and how it may compare to his or her own, I will begin by describing the area of Be'er-Tuvia. Be'er-Tuvia was founded about 60 years ago; the area consists of about 80 family farms, with an average of 60 cows and a total of about 200 dairy cattle per farm. Average milk production per cow is 7500 liters annually. Management is progressive: Every farm has a modern milking parlor, a calf barn, and modern equipment. The farms are situated in close proximity to each other, and the agriculture fields are all outside the borders of the village. This arrangement was designed for security reasons. Up to 15,000 animals are kept in a relatively small area, resulting

*Veterinary Surgeon "Hechaklait," Be'er-Tuvia, Israel Veterinary Clinics of North America: Food Animal Practice-Vol. 6, No.1, March 1990

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in overcrowding, which undoubtedly contributes to the high incidence of neonatal calf diarrhea. It is my impression that the incidence of calf diarrhea is greatest in the winter, when the difference between day and night temperatures is the greatest. The causes of neonatal calf diarrhea in Be' er-Tuvia and in Israel in general are similar to those found throughout the world. 13 The most common are enterotoxigenic E. coli K99 (ETEC) , rotavirus, coronavirus, Cryptosporidium, Salmonellae, and other less pathogenic and less common microorganisms that have been isolated in this area. Rotavirus has been diagnosed in Israel by electron microscopy12 and in Be'erTuvia by fluorescent immunomicroscopy and commercial ELISA kits. An epidemiological survey of the viruses in our area is planned. Calf-raising husbandry practices are generally good. Calves receive hyperimmune colostrum with the first feeding, produced by maternal vaccination with E. coli K99 antigen. This practice has greatly reduced the number of cases of neonatal diarrhea that require treatment with intravenous rehydration therapy. The herdsman initiates treatment of calves that suffer from severe diarrhea; the veterinarian does not become involved in treatment unless generalized symptoms such as depression, fever, or anorexia become apparent. Basic initial treatment consists of the following electrolyte mixture 2: Sodium bicarbonate Sodium chloride Potassium chloride Glucose Water

14.5 g 19 g 2.2 g 72 g 5L

In documented cases of ETEC infection, additional glucose is used. 2 The method of administration of fluid therapy varies according to the calf s condition. Oral rehydration fluids are offered to calves that will drink spontaneously from a pail, but in most cases a nursing bottle or stomach tube is required to successfully administer the solution. No milk is given to the calf during the first 24 hours of treatment, but after that period half of the usual amount of milk is supplied to provide energy, since the scouring animal suffers from a negative energy balance. s Treatment with the electrolyte mixture is continued until the stool consistency improves. Ideally, small amounts (1-1.5 L) are supplied frequently. Treatment with astringent enteric drugs such as tannic acid, adsorbents such as activated charcoal, and mucous membrane coating drugs such as bismuth-salt mixtures are occasionally used. In severe cases, the veterinarian administers antimicrobial drugs orally as well as by injection; those used most frequently are potentiated sulfonimides, neomycin, ampicillin, amoxicillin, and gentamicin. It is my opinion as well as the opinion of others that, while the value of antimicrobials is doubtful in most cases and the old-fashioned nonantimicrobial drugs are somewhat beneficial, fluid therapy is life-saving 13 (Fig. 1). In Be' er-Tuvia, approximately 120 calves are treated by intravenous

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Figure 1. A, Severely dehydrated calf before treatment. Note the sunken eye. B, Same calf 6 hours later, after intravenous fluid therapy, as described in the text.

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infusion annually. Indications for parenteral fluid therapy include the following: 1. 2. 3. 4. 5.

Severe diarrhea Absence or depression of suckle reflex Severe dehydration Unwillingness or inability to stand Weak or absent pain reflex

Our objective is to reserve intravenous rehydration therapy for those calves that would not survive without it. Although no laboratory tests are used to assess the condition of the calf, I feel that careful physical examination by an experienced veterinarian is adequate to determine which calves require intravenous therapy. The technique for intravenous rehydration therapy has been described. 16 The catheter is introduced into the vein and secured to the skin with Superglue (Duro, Loctite Corp). In cases of severe dehydration, it may be extremely difficult to insert the catheter. In approximately 40% of the calves we treat by intravenous infusion, a jugular vein cutdown is performed. INTRAVENOUS FLUID THERAPY The materials used are a Jelco intravenous catheter (Jelco Laboratories, Raritan, NJ 08869), an intravenous fluid administration set with filter, and commercially prepared intravenous solutions (Travenol Laboratories Israel, Ltd, Ashdod, Israel); the solutions are supplied in l-L plastic bags (Fig. 2). Our standard treatment protocol is as follows: 1 L lactated Ringer's solution 0.5 L 5% sodium bicarbonate solution 1 L 5% dextrose solution 3 L lactated Ringer's solution To one of the bags of lactated Ringer's solution, 3 g of amoxicillin is added. The rate of administration is approximately 150-200 drops/ minute, or about 10-15 ml/minute. It is advisable to decrease the rate of administration for bicarbonate solution. Total treatment time usually takes approximately 6 hours. The farmer monitors the treatment continuously. There is often a marked improvement in the condition of the dehydrated calf after 2 - 3 L of fluids have been administered. Enophthalmos disappears, mucous membranes become moist, and suckle reflex returns. A particularly useful indicator of the status of a dehydrated calf is body temperature. Calves with severe dehydration usually suffer from hypothermia, which is occasionally profound. Many calves have rectal temperatures below 35°C. During successful intravenous rehydration therapy, the rectal temperature starts rising, probably owing in part to the dextrose infusion. 1o In my opinion, an increase in rectal temperature is a very valuable, positive prognosticator. As recovery

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Figure 2. All that is required to save a dehydrated calf.

proceeds, the animal begins to move and clearly reacts to pain applied to the extremities. At this point, it is often necessary to immobilize the calf to prevent interruption of the fluid flow. As soon as the suckle reflex returns, we recommend the commencement of administration of oral rehydration solution. In most cases the response to intravenous therapy as described above is dramatic. The animal stands and drinks spontaneously after all the fluids have been administered, but it is often necessary to repeat intravenous rehydration therapy on the following day. For this reason it is advisable to leave the catheter in place for at least 24 hours. Rationale Behind This Protocol In diarrheic calves, electrolyte as well as water losses occur. Sophisticated measurement of the degree of dehydration, base excess, and electrolytes are not readily available in practice. I •6 In general, a total amount of 6 L of fluid suffices to at least partially rehydrate most dairy calves. In addition to the intravenous fluids, oral fluids are also administered to replace the deficit as well as to provide maintenance fluid and compensation for continued loss. 9 Lactated Ringer's solution will provide water and volume replacement and will partially correct acidosis and some electrolyte abnormalities. Twenty-six of 28 scouring calves experimentally infected with rotavirus and/or ETEC showed a distinct acidosis 3 (Fig. 3). The importance of providing alkalinizing agents in rehydration solutions has been demonstratedl ; consequently, I assume that every dehydrated calf suffers from some degree of acidosis and needs specific alkalinizing therapy.4,6,7 A base excess of -20

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Figure 3. Fluctuations in blood pH values of 28 experimentally infected calves (values and range). (From Hofmann W, Zschoeck M, Koberg J, et al: Experimentelle Untersuchungen zur Erzeugung und Bekampfung von Kalberdiarrhoen. Tierarztl Umsch 42:303, 1987; with permission.)

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mEqjL is a common finding. The formula to determine the total bicarbonate requirement of a neonatal calf is: Base deficit (mEqJL) X 0.6 X body weight (kg)

= bicarbonate (mEq).2.9

Applying this formula to the severely dehydrated calf with a base excess of -20 mEqjL gives the following formula: 20 X 0.6 X 40

= 480 mEq.

Five hundred ml of 5% sodium bicarbonate solution contains approximately 300 mEqJL of bicarbonate, which provides a substantial portion of the required amount of base for the severely dehydrated calf. Most scouring calves are in a negative energy balance. Neonatal calves have relatively small body fat stores. Calves suffering from severe diarrhea will probably deplete their' energy reserves in a few days.17 Dextrose helps to supply energy to the calf and prevent starvation caused by diarrheal malabsorption and a low caloric intake when milk is withheld during oral rehydration therapy. Although most fluid loss and diarrhea are isotonic, some free water is lost by respiration and urine formation.ll.14.15 The 5% dextrose solution provides energy as well as free water.

CONCLUSION The purpose of this paper is to convince the practitioner of the value of intravenous fluid therapy, even when sophisticated laboratory analysis is unavailable. Disappointments are not rare. The dehydrated calf is frequently in a coma. Perhaps laboratory tests would suggest that the calf is "beyond hope"; intravenous rehydration therapy would not be beneficial in these cases. However, the results of intravenous therapy are often gratifying. Few treatment modalities in veterinary practice are so clearly life-saving. The estimated success rate of our treatment protocol is approximately 50%. Remember that only calves that would be expected to die if not treated are given intravenous treatment. In the opinion of this author, our success rate is high enough to justify the extra effort of this treatment.

REFERENCES 1. Booth AJ, Naylor JM: Correction of metabolic acidosis in diarrheal calves by oral administration of electrolyte solutions with or without bicarbonate. J Am Vet Med Assoc 191:63-68, 1987 2. Breukink HJ, Hajer R: Oral administration of a glucose electrolyte solution as an adjunct in the treatment of colibacillosis in calves. Tijdschr Diergeneesk deel 99, aH. 21, 1974 3. Hofmann W, Zschoeck M, Koberg J, et al: Experimentelle Untersuchungen zur Erzeugung and Bekampfung von Kalberdiarrhoen. Tierarzt Umsch 42:300 - 307, 1987

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4. Kasari TH, Naylor JM: Clinical evaluation of sodium bicarbonate, sodium L-Iactate, and sodium acetate for the treatment of acidosis in diarrheic calves. J Am Vet Med Assoc 187:392-397, 1985 5. Moon HW: Mechanisms in the pathogenesis of diarrhea: A review. J Am Vet Med Assoc 172:443 - 448, 1978 6. Naylor JM: Severity and nature of acidosis in diarrheic calves over and under one week of age. Can Vet J 28:168-173, 1987 7. Naylor JM, Forsyth GW: The alkanizing effects of metabolizable bases in the healthy calf. Can J Vet Res 50:509-516, 1986 8. Phillips RW: Fluid therapy for diarrheic calves: What, how, and how much. Vet Clin North Am [Food Anim Pract] 1:541-563, 1985 9. Roussel AJ: Principles and mechanics of fluid therapy in calves. Compend Contin Educ Pract Vet 5:S332-S339, 1983 10. Scholz H, Hoppe S: Renale Glukoseverluste nach intravenoser Glukoseinfusion beim Kalb. Dtsch Tierarztl Wschr 94:473-476, 1987 11. Tennant B, Harrold B, Reina-Guerra M: Physiologic and metabolic factors in the pathogenesis of neonatal enteric infections in calves. J Am Vet Med Assoc 9931007, 1972 12. Tromp A, Davidson M, Shahar A, et al: Detection of Rotavirus in faeces of calves in Israel. Meeting of the Organization of E. M. Scientists, Rehovot, 1978 13. Tzipori S: The aetiology and diagnosis of calf diarrhoea. Vet Rec 108:510-514, 1981 14. Watt JG: The use of fluid replacement in the treatment of neonatal diseases in calves. Vet Rec 77:1474-1482, 1965 15. Watt JG: Fluid therapy for dehydration in calves. J Am Vet Med Assoc 150:742749, 1967 16. Watt JG, Stenhouse A: Method for continuous drip therapy. Vet Rec 78:642-647, 1966 17. Youanes YD, Herdt TH: Changes in small intestinal morphology and flora associated with naturally occurring diarrhea. Am J Vet Res 48:719-725,1987 Address reprint requests to: Aaron M. Tromp, MedVet, Drs Veterinary Surgeon "Hechaklait" Be'er-Tuvia 70996 Israel