Abstract

Ketosis is a metabolic disorder affecting dairy cattle typically in early lactation. The disease is characterized by a negative energy balance resulting from a decrease in feed intake and an increase in energy requirements caused by milk production.  In order to compensate for this imbalance, there is an increase in fat mobilization to the liver and increased hepatic ketogenesis, which leads to a high level of ketone bodies in the circulation, milk and urine.  The history and clinical signs typical of the disease are: a decrease in milk production, inappetence, loss of body condition and depression.  The losses resulting from this condition derive from the cost of the treatment and also, if not mainly, due to impairment of productivity of the cow as expressed in lower milk yields and decrease of reproductive ability.

The important principles for a successful treatment of ketosis are:

Restoring blood glucose levels as quickly as possible, and consequently the levels of insulin., replenishing oxaloacetate so that fatty acids mobilized from fat deposits are completely oxidized and thus reduce the rate of ketone bodies production and increasing  the availability of dietary glucogenic precursors, notably propionic acid, in order to increase glucose production through gluconeogenesis.

The most common treatments are: an intravenous infusion of 500ml of 50% dextrose, oral administration of glucose precursors such as propylene glycol, once a day for three days, and administration of glucocorticoids.  As for today, there is no single accepted therapy used by all veterinarians for the treatment of the disease, and the different therapies are based on different combinations of the treatments mentioned above.

The objectives of our study were to compare the efficacy of different treatments commonly used in Israel, and their effect on recovery, reproduction, and cumulative 305 day lactation yields.  The experiment was conducted between July 2005 and July 2006, in five dairy farms which are clients of the ambulatory farm animals clinic of the Koret school of veterinary medicine in Rehovot. All these farms are generally treated by veterinarians belonging to the "Haklait". In total, 1847 cows were included in the study. They were divided into 3 main groups: healthy cows, cows with mild ketosis, and cows with severe ketosis.  Mild ketosis was defined as urine acetoacetate levels of 1-4 mmol/L and the cows affected were given oral therapy with propylene glycol. Severe ketosis was defined as levels higher than 4 mmol/L of acetoacetate in the urine. One hundred and fifteen cows were found to have severe ketosis and they were assigned to 4 treatment groups according to the burn number – even or odd -  and the farm. The control group – treatment group no. 1 - received all three therapy possibilities: 500 ml intravenous infusion of 50% dextrose, an intra-muscular injection of 10 ml dexamethasone, and oral administration of propylene glycol once a day for 3 days.  Treatment no. 2 included the dextrose infusion with a dexamethasone injection, treatment no. 3 included dextrose infusion and oral administration of propylene glycol and treatment no. 4 included a dexamethasone injection and propylene glycol. Recovery was defined as absence of acetoacetate in the urine in the following veterinarian visit.

 We found, that healing was significantly influenced by the treatment.  The most effective treatments, with no significant difference between them, were the control group and treatment groups no. 2 and 4, both including dexamethasone administration. Treatment no. 3 – dextrose and propylene glycol administration – was significantly less effective than the control group (OR=0.039, P=0.004).  Our results suggest that there is a need of including dexamethasone injections in  treatment of severe ketosis in cows.

We found no significant difference between the different groups regarding the following reproductive parameters: first artificial insemination conception rate, cows empty at 150 days in milk, anestrus, inactive ovaries, empty days and pregnancy rate in a survival model. Nonetheless, there was no un-treated control group in this study so that we could not assess the damage in a non-treated ketotic cows compared to other groups.  An interesting find was a difference between the mild ketosis group and the rest of the cows – these cows showed lower rates of pregnancy at first insemination and higher rates of pregnancy after 150 days. This hints at the need to treat these cows more intensively then done today in order to minimize the damage caused by the condition.

We found no difference between the groups considering corrected milk yield at 305 day. There was a significant influence of the treatment on milk yield but not on Economy Corrected Milk.  The highest yield was found in the group given the control treatment. The lowest was, like in the healing model, treatment group no. 3, with a 1,070 kg milk difference between them. This result again emphasizes the need to include corticosteroids in the therapy and one may assume that without treatment at all, there would have been a difference between the healthy and severe ketosis groups.

In summary, treatment of ketosis should include Glucocorticoids with IV dextrose infusion and/or propylene glycol drench to improve healing rates of the cows.