The end of January and early February usually heralds the start of the calving season. This is generally an extremely busy time on farms, with cows calving and newly born calves to be fed and cared for along with all the other usual jobs.
However, herd sizes are increasingly resulting in extra demands on labour and less available time for individual attention to calves. Increased herd sizes can also put a strain on the health status of the herd.
Indeed, data from the CMMS indicates that mortality rates of calves born to a dairy bull are currently 8-9pc, excluding stillbirths, which account for around 2pc of pregnancies. Approximately half of these deaths occur within the first six weeks of a calf's life. In a recent survey conducted by Animal Health Ireland, to elicit opinions from experts and farmers regarding animal health issues facing the Irish livestock sector, calf health was identified as one of the main problems. Planning and preparation for the impending calving season, along with the implementation of a few simple measures, can help reduce on-farm mortality levels.
When the calf is born there are two key things to remember: i) iodine for their navel and ii) colostrum. When applying iodine to the calf's navel, use a tincture of iodine -- it contains alcohol that will help dry the cord and discourage pathogen movement up the cord, reducing the risk of navel-ill and joint-ill.
Do not be tempted to use an iodine-based teat dip as it contains emollients intended to keep teats soft and pliable, and will not dry the umbilical cord.
Colostrum (biestings) is the cow's first milk after calving and is present for up to six milkings. At birth, a calf's immune system is not fully developed, and colostrum imparts passive immunity from the dam to the newborn via intestinal absorption of antibodies. Generally a calf should receive 5-6pc of its body weight (typically 2 litres) in colostrum within the first six hours of life, and another 5-6pc of its body weight when the calf is eight hours old. As time from birth increases, the ability of the calf to absorb the antibodies is reduced. Therefore, it is critical to feed colostrum as soon as possible after calving to ensure maximum long-term immunity is acquired. Colostrum feeding should continue for three days after birth. The ideal source of colostrum is the calf's own dam -- for two main reasons: i) it minimises the potential spread of Johnes Disease and ii) the calf will acquire immunity to fight pathogenic organisms encountered on the home farm.
Data from the CMMS has also shown that the number of calves being born to a dairy sire is increasing. An increase in herd size will necessitate the provision of extra accommodation. Given the harsher economic times, there is less free capital available for building new infrastructures to house calves, therefore alternative options need to be considered. Furthermore, poorly ventilated, low-roofed houses that are highly stocked are risk factors for disease, thus outdoor rearing of calves is a viable alternative.
A recent experiment carried out by Teagasc Moorepark investigated if calves could be turned out at around one week old without compromising weight gains and vitality when compared to calves reared indoors. Preliminary results from the first year of the study indicate that there is no difference in weaning weight between the indoor and outdoor rearing systems. However, it was deemed necessary to provide shelter for all calves outdoors. This can range from straw bales in an 'X' shape to a more permanent shelter, such as an old house, where calves can have access to both a paddock and shelter.
Rearing the pre-weaned calf can be very labour intensive. Around 7pc of labour input each day on a dairy farm is associated with calf care over a 12-month period. However, the peak labour requirement for calf care occurs during a 12-week period on a typical spring-calving herd. An ideal scenario would be to minimise the labour input required during this time yet not compromise calf welfare.
A study investigating the labour input associated with calf care on Irish dairy farms was carried out by Teagasc Moorepark. This study found that practices such as grouping calves and feeding once a day will reduce labour. From the table (above), it is evident that once-a-day feeding requires the least labour input (23 seconds/calf/day). In addition calf weight at 77 days is not adversely affected.
It should be routine to offer meal to calves from an early age. Consumption of meal increases when calves transfer from twice-a-day milk feeding to once-a-day. It will also be apparent that calves reared outdoors tend to eat more grass as the rumen develops and they make the transition from milk to solid food. Given the greater requirement of the calf for solid food, more meal and/or fresh grass should be offered at regular intervals. Ideally low grass covers should be maintained for calves.
One of the big issues to be mindful of with young calves is scour. Scour -- or diarrhoea -- is one of the most common conditions seen in young calves, particularly in the first month of their lives. Many infectious agents, such as rotavirus, coronavirus, E Coli and Cryptosporidium, can cause diarrhoea, as can nutritional factors. When calves have diarrhoea, the lining of the bowel is damaged, which results in the loss of large amounts of body fluid. Consequently, the calf quickly dehydrates, electrolytes become unbalanced and energy reserves are depleted. The treatment of scour in calves should aim to replace lost body fluids, correct the electrolyte imbalance and supply energy. Ideally, prevention is better than a cure. The following guidelines should be kept in mind to try and prevent the occurrence of calf scour: