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23rd February, 2019


This is a busy time of year on spring calving dairy farms.  The hours worked can extend to 18 hours a day for the full week.  There is little opportunity for social outlets.  This is a critical stage in the production cycle of the dairy herd.  The transition outcome for the freshly calved cow will dictate in large part her lactation curve and reproductive performance.


The future replacements born now for two years time need a successful start in life.  Calving difficulty will not alone increase the risk of pregnancy failure but also mortality in newborn calves.  Cows and heifers need to be fit at calving time.  The over-conditioned cow has both an increased risk of calving difficulty and metabolic disease such as Ketosis and fatty liver.


It is essential that the calf gets colostrums within the first two hours of life.

feeding calfThe quality and quantity of the colostrum produced by the cow will in large part be dictated by transition management.  Cows which are stressed precalving because of diets, housing environment, metabolic disease will produce poorer quality colostrum.  It is essential to have a stock of frozen colostrum available where the health of the freshly calved cow is compromised.


Previous practice of group feeding colostrum should be avoided based on the risk of input transmission of Johnes’ disease.   Current assays for the detection of Johnes’ disease require animals to be four years of age for a high reliability of positive cases. Johnes disease will cause impaired health status with immune system depression culminating in clinical symptoms associated with progressive weight loss, diarrhoea and impaired reproductive performance.


Therefore, management practices around the time of calving have to ensure the risk of disease transmissions are minimized.  Faeces are another source of disease transmission.  It is essential that calving boxes are kept clean whereby calves do not have access to input faecal contaminated bedding and feedstuffs.  This will require extra diligence as the calving season proceeds and management practices slip.



Why such emphasis on Johnes’ disease management?

Previous studies have shown the presence of the causative organism mycobacterium avian paratubercolosis in the polyps of humans with Crohns disease.  Therefore, it will in the future be essential to have disease management protocols in place to satisfy marketing requirements.


A number of our clients in the North of Ireland have introduced pasteurization of colostrum to minimize the risk of Johnes’ disease transmission.  In addition, they have refrained from the use of whole milk input and resorted to pasteurization of colostrum facilitating group feeding of calves.


It is in the interest of your business to have a Johnes’ disease management strategy as the disease can be spread easily, will reduce herd longevity and increases herd health management costs associated with immune input system.  It is noteworthy that Australia has implemented a Johnes’ disease management strategy approximately 15 years ago.  They have failed to eradicate the disease and concur that disease tolerances will have to be accepted for most herds.


Having established that your calves have sufficient immunoglobulins, that housing environment does not create stresses resulting in pneumonia, coccidiosis or cryptosporidium.  As the number of calves increase in the house, it is essential that ventilation is correct with adjustment for cold and warm days and varying wind speeds.  Coccidiosis and cryptosporidium result in severe setbacks with significant calf mortality.  Calves may recover following treatment for pneumonia and various calf scours.  However, these events may have adverse epigenetic effects on subsequent expression of genetic potential to establish pregnancy.  There is research data showing adverse effects of these events on the onset of reproductive cycles and fertility when the heifers were 13 to 16 months of age.  Physically these heifers will not be different to their fertile counterparts.


In conclusion, newborn calves are replacements for the dairy herd in two years time.

Ensure they get the right start with excellent colostrum avoiding risk of Johnes’ transmission.  Having calves off to a good start, it is essential to avoid epigenetic effects on subsequent reproductive performance when heifers are 15 to 18 months of age.


Dr. Dan Ryan is a cow fertility expert and can be contacted at


Article written by Dr. Dan Ryan in The Farming Independent February 11th 2014.