Diarrhoea remains of the most significant health and welfare problems in young calves.
In Ireland, diarrhoea is the most common cause of death in calves from birth to one month of age submitted for post-mortem examination, accounting for 38 per cent of neonatal deaths in Northern Ireland and 27.6 per cent in Ireland.
Diarrhoea is frequently seen as a chronic problem on farm - one that prevents maximal growth rates from being achieved. Data from the AFBI Hillsborough herd has shown that scour not only increased the mortality rate of pre-weaned calves by 3%, but that it also had a significant negative impact on future animal performance, with a 12 kg reduction in live weight seen at 18 months.
With age at puberty in heifers linked to physical development, reduction in growth rates can lead to a delayed age at first calving, thus impacting on animal productivity and profitability.
Enterotoxic Escherichia coli (E. coli), Cryptosporidium parvum (Crypto), rotavirus and coronavirus are the most common causes of infectious diarrhoea in young calves under three weeks of age.
These infectious agents can be found in faecal samples from healthy calves and in calves from farms without scour problems. Clinical disease develops as a result of an unfavourable balance between the ability of the calf to fight infection and the infectious pressure. The main management factors which can improve the resistance of the calf are the prevention of calving difficulties, timely provision of sufficient good quality colostrum (three litres of first milking colostrum in the first two hours of life followed by a further litre at six hours of age) and an appropriate diet thereafter.
The infectious pressure can be lowered through general hygiene in the areas of calving, feeding, housing and in general calf handling.
Using vaccines such as Lactovac® in cows in late pregnancy can boost colostral antibodies levels to Rotavirus, Coronavirus and K99 E.Coli.
Antibodies are absorbed through the calf’s gut wall for the first 24 hours of life and if milk or colostrum from vaccinated cows continues to be fed for longer, then antibodies in this milk will also give local protection in the gut.
All cows in the herd should initially receive two injections, given four-five weeks apart, during the later stages of pregnancy, and allowing two-three weeks from the time of the second dose until the predicted date of calving. During each subsequent pregnancy previously vaccinated cows should receive a single injection two-six weeks prior to the predicted calving date.
Coccidiosis is commonly a disease of young cattle from one-two months of age up to one year old.
The economic impact of clinical and subclinical coccidiosis on the farming industry is considerable, due to both cost of treatment and impaired performance of affected animals.
Calves get infected through environmental challenge and adults act as a reservoir of disease. In dairy heifer rearing units with a history of disease, hygiene and cleansing of accommodation in between batches is crucial for reducing incidence of disease. Suckler calves are at risk of infection through soiled drinking troughs and poaching of land surrounding creep feeders and troughs. While most infections remain subclinical, clinical outbreaks may occur as a result of high environmental challenge in conjunction with a period of stress such as concurrent disease (e.g. BVD), poor colostrum intake, mixing groups of calves, weaning, dietary changes, etc.
Clinical signs in acutely infected calves include bloody, mucus tinged scour, lethargy, dehydration, inappetence, severe straining and sometimes death. Chronic forms of coccidiosis can be associated with ill thrift and under performance, pasty scour, reduced appetite and straining.
Deccox®6%, added to feed as a prescribed premix, can be used to prevent coccidiosis in calves at risk. Deccox®6% should be fed continuously for 28 days when coccidiosis is expected to be a hazard. The major benefits of coccidiostats are through improved feed efficiency and weight gain.
Control of infection should include changes in management factors that contribute to the development of clinical disease. Inadequate housing and ventilation should be corrected, feeding practices adopted that avoid faecal contamination of feed, calves grouped by size, and an “all-in/all-out” method of calf movement from pen to pen adopted.