Dairy cow diseases pose a serious threat to cattle production worldwide. Often underestimated, these health issues lead to significant economic losses for producers around the World. The aggregate impact of these diseases amounts to 65 billion (B) US$ (~ 60B€) in annual losses worldwide, meaning approximately 351 US$/cow/year (~323 €/cow/year). This is a troubling reality for farmers who work hard to maintain their production.
A recent study simulated the losses in dairy production in 183 countries, allowing an immersive and realistic estimate of global losses of this sector. A meta-analysis that helped adjust results accounting for comorbidities allowed conclusive numbers, reduced by 45% through this adjustment.
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Subclinical ketosis is associated with energy metabolic disorders and a subsequent negative energy balance, caused by insufficient feed intake, very common in transition dairy cows. It is defined as the increasing of circulating ketone bodies and concurrent low level of glucose without clinical signs. In Europe the prevalence has been estimated to be 25%.
Mastitis is a multi-etiological disease resulting from inflammation of the mammary gland tissue manifested by physical, chemical and bacteriological changes in this gland tissue. It is more common in cows with high milk production and associated with the production system, and the farming environment. Prevention is crucial in this disease as treatment can be difficult and lead to high losses. When the condition is clinical, the signs are clearly visible, including a reduction and alteration in milk production, as well as changes in the udder’s appearance, such as swelling, hardness, and increased sensitivity.
Subclinical mastitis is the same as mastitis but is a non-symptomatic form and can affects 20–50% of cows in given herds, making this the most frequent form of mastitis. Caused by specific groups of pathogens, it results in distinctive degrees of changes in milk yield and composition.
Lameness constitutes any foot or leg condition, either of infectious or non-infectious origin, that negatively impacts cow mobility, posture, and gait. It is associated with reduced milk yield, lack of weight gain, poor fertility, and frequently, animal culling. It is not a single disease in dairy cows but is the manifestation of a range of issues, making lameness control one of the greatest challenges in dairy farming.
Metritis is defined as the inflammation of the uterine wall, including the endometrium, the muscular layers and the serosa, making normal uterine involution impossible. It occurs within the first 21 days after calving and can affect up to 40% of dairy cows. Usually, the signs include watery red-brown uterine discharge with a fetid odor.
This is an infectious inflammatory disorder of the intestines, progressive and insidious, that can cause scour and weight loss in adult cattle, usually over four years of age, and is a difficult disease to control within herds. It is caused by Mycobacterium avium ssp. paratuberculosis and, unlike tuberculosis, is not considered a zoonosis.
Ovarian disorder is characterized by abnormal cyclicity with the presence of persistent follicular structures for more than 6 days in the absence of a corpus luteum in certain conditions this structure can have a partial luteinization and become known as luteal cysts.
This pathological condition is associated with reduced fertility and an increased risk of culling. The treatment of the symptom appears to be simple. However, regaining fertility, often requires longer time due to perturbations in endocrinology and uterine pathology that follow in long standing cases, can be more important.
This disease is very common in postpartum cows, typically defined as a failure to expel fetal membranes within 24 hours after calving. Abortion, dystocia, twin birth, induced parturition, hypocalcemia are some risk factors for this disease.
Displaced abomasum is a multifactorial disorder diagnosed almost exclusively in adult dairy cows and very common in high producing dairy herds. It is characterized by the displacement of the abomasum from its normal position to the left or right side in cows, with left abomasal displacement being more frequently diagnosed than right.
Like ketosis, hypocalcemia is a metabolic disease. Occurring at the beginning lactation, it is characterized by low total serum calcium and inorganic phosphorus. The incidence of the disease generally varies from 0% to 10% but can exceed 25%. Milk fever can be considered an entry disease, greatly reducing the chance of complete productivity throughout subsequent lactation and has been associated with greater chances of other diseases in lactating dairy cows.
Dystocia is the difficulty or inability to give birth through one's own efforts, often resulting in the death of the calf and, in more serious cases, the death of the cow. It is common in very productive cows or overweight animals. The birth weight of the calf, fetal malposition, congenital deformities and the size of the pelvis are some of the determinants of dystocia, which most of the time require veterinary intervention.
It has the same origin that subclinical form but in this case the animals have symptoms like weight loss, anorexia, decreased milk production, firm and dry feces, acetone smell in cow´s breath and, in some cases. neurological signs.
If body fat mobilization is excessive it can surpass the liver capacity to metabolize that fat, causing accumulation in the liver, which can result in ‘fatty liver’. This causes liver dysfunction and can even cause permanent damage, making the animal more susceptible to all kind of diseases.
Economic losses are considerable due to decreased milk production and cost of treatment. To prevent this, ensure that your cows have access to a high quality, palatable and well balanced diet.
Using the data from this study, it’s easier to create visual graphics to compare potential financial costs of different diseases, as well as compare them globally.
Graph 1: Economic Impact of Dairy Cow Diseases (in Billions of US Dollars)
Graph 2: Global Economic Losses by Region (in Billions of US Dollars)
References
Jeengar, K., Chaudhary, V. Kumar, A. Raiya, S. Gaur, M., Purohit, G.N. (2014) “Ovarian cysts in dairy cows: old and new concepts for definition, diagnosis and therapy” in Animal Reproduction Journal volume 11 pp 63-73 https://doi.org/10.1292/jvms.20-0381