Читать книгу Farm Animal Medicine and Surgery - Graham R Duncanson - Страница 153

This is a disease of adult cows called ‘milk fever’. Classically it occurs around parturition when there is a sudden drop in blood calcium levels. The case may be a true ‘milk fever’ around parturition, or in Jersey cows it may be brought on by oestrus. Feeding excess root crops, particularly the tops, will cause hypocalcaemia in growing and adult animals. Also, poisonous plants containing oxalates, e.g. rhubarb, will cause hypocalcaemia. Diagnosis can be confirmed by measuring blood calcium levels. One 400 ml bottle of 40% calcium into the vein should be sufficient for treatment except in a very large cow. There is no evidence to confirm that the solution is better given at blood heat and slowly, but taking these precautions is prudent. If the cow is staggering but not recumbent, it is advisable not to try to give large volumes of fluid iv, and obviously it should not be put in a crush. Trying to inject a staggering cow is difficult and dangerous. The worst scenario is that some fluid will be injected perivascularly. This will make the cow move her head violently, and will either result in injury or the needle will come out of the vein. It is preferable to give the dose sub cut as this will achieve the same blood levels of calcium within half an hour. It is important that after treatment the cow is moved either on to deep muck or out on to the pasture and then propped up on to her brisket in sternal recumbency.