achieved when 124 inseminations with whole straws produced 78 pregnancies. Thus 87 doses of semen were saved but 26 pregnancies were lost by splitting straws. When the program was done, the semen cost was $20/dose saving $1740 at a time when expected prices of Chianina calves were $400 each representing a loss of $10,400. Of coursz, the economics of the practice change with each individual situation. However, the major costs in an A1 program relate to the management costs and the costs of carrying over nonpregnant cows. Therefore, the

only justification for splitting straws would be when the quantity of semen is strictly limited such as after the death of a bull. It is considered that on the basis of the results presented together with other undesirable features, splitting of straws should be actively discouraged.

L. E. DONALDSON, B.V.Sc., M.V.Sc., Ph.D. 154 Russell Street, Indooroopilly, Queensland 4068 18 August 1975


In a series of studies with Babesiu argentina and Babesia bigemina (Hall 1960, 1963; Hall et al 1968) it was found that immunity against these parasites was transferred to calves from immune mothers. The failure to demonstrate a prenatal, immunising infection and the relatively short period of immunity was evidence that protection was mediated by colostral antibodies. The findings provided an explanation for the comparatively few cases of clinical babesiosis seen in young calves born in the enzootic area (Seddon 1967). The purpose of this communication is to report a case of babesiosis in a young calf. The most interesting feature of the case was the probability that infection occurred prenatally. The case involved a Jersey heifer calf which had been weaned approximately 24 hours after birth and removed to a second farm for artificial rearing. When examined on the ninth day after birth the calf had a temperature of 39.6”C. Other clinical signs included diarrhoea, anorexia (of 2 days duration), dehydration, depression and haemoglobinuria. A provisional diagnosis of ieptospirosis was made. Treatment consisted of streptomycin, phosphorous acid - cyanocobalamin sulphate” and fluidst given orally. Haematology values fell within the normal range apart from an elevated neutrophil lymphocyte ratio (Neutrophils 6.56 x 103; Lymphocytes 1.44 x 103). Unfortunately, serum protein levels were not determined and so the effect of haemocentration on these vaIues could not be determined. Examination of blood smears revealed a B. bigemina infection with an 8% parasitaemia. Amicarbalidet was given intramuscularly, on the same day. The calf made a clinical recovery within 2 days of babescidal treatment. Some unusual features of this case were that the calf was experiencing acute babesiosis by the time it was 9 days old, the causative organism was B. bigemina and the disease occurred on a tick-infested farm o n which the mature females were probably immune and able to transfer colostral immunity to their new-born calves. Coforta BIZ. Bayer Australia Ltd., Botany New South Wales. (Ausi.) Pty. Ltd., Dandenong Victona. $ Diadpron; May & Baker Ltd., West Footscray, Victoria.

t Trolyte; ,Tasman Vaccine Laboratory

Australian Veterinary Journal, Vol. 5 1, November, 1975

The timing of the infection suggested that prenatal infection had occurred. Transmission studies (Callow and Hoyte 1961; Hoyte 1961, 1965) have shown that infection with B. bigemina does not occur until Booplrilus microplus is a nymph, 9 days old. Larval transmission was unlikely to have caused the infection because advanced clinical signs and a high parasitaemia were present when the cass was diagnosed. It is, however, recognised that prenatal infection is not a significant mode of transmission of babesiosis (Neitz 1956; Hall 1960). The fact that B. bigemina caused the attack was unusual because this parasite is a minor cause of disease in Australia (Johnston 1968). The findings suggest ,ihat there was either an absence or a depression of passively acquired immunity in the calf. The dam was probably able to provide colostral antibodies but early weaning of this calf may have reduced the amount of colostrum ingested. I wish to thank Dr L. Callow for his personal interest in this case and Dr R. McKenzie for laboratory results. R. B. ATWELL, B.V.Sc. Bundaberg Veterinary Clinic, Bundaberg, Queensland 4670 13 July 1975

References Callow, L. L. and Hoyte, H. M. D. (1961)--Aust. vet. I . 37: 381. Hall, W. T. K. (1960)--Aust. vet. J. 36: 361. Hall, W. T. K. (1963)-Aust. vet. J . 39: 386. Hall, W. T. K., Tammemagi, L., Johnston, L. A. Y. (1968)-Aust. vet. J . 44: 259. Hoyte, H. M. D. (1961)--Pratozool. 1. 8: 462. Hoyte, H. M. D. (1965)--Pratozool. J . 1 2 83. Johnston, L. A. Y . (1968)-Aust. vet. 3. 44: 265. Neitz, W. 0. (1956)--Ann. N . Y . Acad. Sci. 64: 56. Schalm, 0 . W. (1965)-Veterinury Haematology, 2nd edn., Lea and Febiger, Philadelphia. Seddon, H. R., revised by H. E. Albiston (1967)“Diseases of Domestic Animals in Australia”, Part 4, Protozoan and Virus Diseases. Cwlth Aust. Dept Hlth Canberra.


Letter: Prenatal Babesia bigemina infection in a calf.

achieved when 124 inseminations with whole straws produced 78 pregnancies. Thus 87 doses of semen were saved but 26 pregnancies were lost by splitting...
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