All Creatures Great and Small

Milk fever, also known as hypocalcaemia and parturient paresis, is caused by a sudden drop in calcium levels. It seems to be an endocrine disorder that is related to the biological stressors of dairy farming. It usually happens around calving time, and begins with the cow in excited distress, paddling, staring, and staggering. She will then fall to the ground and go into a coma. Before the discovery of a treatment, mortality was 90%. But injections of calcium borogluconate have dropped mortality to 5%. James remarks on how miraculous it felt to deliver this new remedy. Previously, they had used a technique that involved inflating the udder, sometimes with a bicycle pump. In this case, the new medication was an unmitigated success.

Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis, which forms nodules in nearly any organ or tissue of the body. It most commonly affects the lungs, which in cattle causes a hard, dry short cough. Bovine tuberculosis is infectious to humans and can be fatal, particularly in children under 16. The tuberculin test involves tuberculin—an antigen made from an extract of Mycobacterium tuberculosis. When injected under the skin, it will cause a detectable swelling if the animal is infected with tuberculosis. After the development of the tuberculin test, the UK Ministry of Agriculture instituted the Attested Herd Scheme in 1935 intending to eradicate bovine TB by compulsory testing in certain areas and slaughter of any positive cases. James mentions Attestation as an important change for veterinary medicine. Not only did it give vets more government work, but it also reduced other diseases, such as abscesses of the throat, which were caused by the tuberculosis bacteria. Reducing the prevalence of tuberculosis meant that these other diseases also began to disappear.

Although pasteurization had been invented in the 1860s and could reliably kill bacteria that caused tuberculosis, salmonella, and other diseases, it was not mandated anywhere in the UK until Scotland introduced food safety guidance on raw milk in 1983. Potentially three-quarters of all outbreaks of communicable diseases could be attributed to unpasteurized milk. As bovine tuberculosis could be fatal and thousands in the UK fell ill each year, veterinarians like James Herriot were one of the only lines of defense against tuberculosis-infected milk. Although tuberculin testing was time-consuming and exhausting, James remarks that stopping tuberculosis-infected milk from causing sickness and death in children made him proud of his professional work.