Occurrence rate of subclinical metabolic diseases in peri-parturient dairy cattle
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As I am from a farming back round, and would like to work as a cattle vet, I feel that by doing this thesis it will allow me to give fundamental advice regarding Herd Health, Nutrition and Management. As I have seen a lot of diseases on work experience, especially Milk fever and Ketosis. The wisdom which I will be able to pass on to farmers and their staff is of huge value to them. Farming today has become more and more about herd health rather than the individual animal. This has resulted in an increase in productivity and profitability. Due to this, there is an increased amount of farmers performing the Compton Metabolic Profile test. Blood and urine samples are collected and brought to a lab where they are evaluated. By evaluating the data of randomly chosen cows within 6 groups, we are able to see the general health status of the whole herd. The farmer is informed of any problems which might be present. The staff members are advised about how to counteract the problems. This is extremely beneficial to the farmer as they have the opportunity to change factors within their Management or nutrition program before signs of a clinical disease appears. This is more economical to the farmer, for instance, if the animals are being fed a ration too high in easily fermentable carbohydrates they are more susceptible to Displaced abomsum. Displaced abomasum is treated surgically and it is very expensive. The samples taken will show that the ration is too high and amendments can be made straight away. In the farm which I evaluated, I found that the mean BCS were all within an acceptable range. There were one or two animals which had a BCS of 2. These animal were in the Peak lactating group, at this stage they have surpassed the critical period and are able to deal with the low energy store. However anything below 2 is unacceptable therefore thses animal should be monitored closely. There were a certain number of animals which were showing signs of subclinical ketosis. These animals were in the close up group, the fresh cow group and the early lactating group. Although these animals had a relatively good BCS between 3- 3.5 this is the critical period in which they are under huge stress in order to provide nutrients to the mammary gland. It is important that over conditioning of the cow should be avoided in the dry period and in the lead up to parturition as it leads to appetite suppression, weight loss and lipid mobilisation. This is done by providing a diet which has no concentrates (gradually increasing the amount towards the end of the dry period) and a high fibre diet. In the days just before and after parturition there is a decrease in feed intake. It is important to provide highly palatable hays to maximize feed intake. It is also important that they animals get sufficient amount of exercise. It is possible that in these cows supplementation of propylene, glycerin or glucose can be given. One animal showed signs of Fatty liver syndrome, this is very worrying on behalf of the whole herd. It is important that the farmers put into place preventive measures similar to those for ketosis. Fatty Liver Syndrome results in a huge economical loss as the recovery rate is low and usually leads the culling of the animal. In some cases the animals had elevation of AST alone. This would indicate that the animal has some skeletal injury. In this case it is important that staff make sure that the animals are not over- crowded, that they are housed with animals of their own ages to avoid any higher- archy dominance, the floor and the bedding area is not slippery. An elevation of Urea and AST indicated to me that the animals were being a fed a diet too high in CP, there must be a balance between the protein and energy intake to allow for maximum utilization. If the protein content is too high it can lead to fertility problems and liver damage. In this case I would advise the farmers to decrease the protein being supplied to the animals and do a ration analysis as stated already with regards to the UDP content. Beta Carotene values were low in all the animals. This is very worrying as it can also lead to a decrease in the amount of Vitamin A. A deficiency in both of these can lead to fertility problems and retained foetal membranes. In this case it is important to ensure that the environmental temperature is not too high, that there is not high nitrate content in the feed and supplementation of Beta Carotene should be provided. A lot of the animals also showed signs of an overload of easily fermentable carbohydrates. This was indicated by the low pH and NABE. This is worrying as it can predispose to Displaced abomasum. It is important that the animals are gradually introduced to increasing amount of highly fermentable carbohydrates. In this case I would advise the farmer to decrease the concentrate ration and increase the fibre content of the feed. Although this farm had no problem with their Ca levels I would still advise them to keep their Ca levels low in the dry period. It is also useful to give a relatively acidic diet in the run up to parturition, this will aid in the mobilization of Ca post calving. The last tip I will give to this farmer and his staff is to avoid stress to the animals.