A dry cow means a lot less trouble in the future
MANY researchers, and successful dairy farmers, regard nutrition and management of dry cows more important, and as difficult to manage, as milking period management.
Their aim is to have cows drying off and calving down at condition score (CS) 3. Adequate energy, minerals and trace elements are very important.
Many put major effort into developing an effective dry cow management plan. The Dairymaster and Alltech companies have combined to devise the very successful, largely automated Cow Centric feeding system to ensure that each cow gets her requirements.
As well as infertility, mastitis and production problems, which are obvious to farmers, there are many other very serious health problems associated with dry cows being over or under fed, or not being properly supplemented with minerals/trace elements. Dr Finbar Mulligan, from the UCD Vet and Science College, has frequently outlined the cost of diseases such as milk fever, ketosis, fatty liver, acidosis, retained placentas, metritis, difficult calvings, laminitis, lameness, mastitis and displaced abomasums. He says that up to 90% of associated losses can be sub-clinical or sub-acute, and may not be obvious to farmers.
Metabolic diseases around calving time and in early lactation cause major losses on many farms, and account for much of the huge difference in profitability between similar type farms. The risks are greater in cows bred for high yields. He suggests that preventative measures are essential. Otherwise, one problem is likely to lead to others — for example, cows that get milk fever are eight times more likely to get other problems.
Poor nutritional status increases culling rates and metabolic diseases; reduces fertility, milk yield and composition; increases lameness and mastitis; and can devastate profitability.
Having cows too fat can be as bad as too thin. Dr Mulligan says the most important time for proper nutritional status is in the weeks leading up to calving and in early lactation, until cows are back in calf.
He has shown that a large reduction in feed intake and energy balance before calving is related to slow and difficult calving and retained placenta, fatty liver and ketosis, displaced abomasum, reduced feed intake and production after calving, reduced fertility, and immunosuppression (leaving animals susceptible to other diseases).
Based on these finding, there is obviously no alternative to having dry cows at the correct condition score. Ideally, they should be dried off at CS 3, and maintained at that condition score until calving. Cows that are too thin at calving will have low production and will be vulnerable to many disease problems and infertility.
Loss of condition between calving and breeding has a major effect on fertility. Large scale Moorepark farm trials indicated that cows that lost half a CS or more had a much lower conception rate than those losing only a quarter of a CS score.
A SUDDEN change in diet after calving can lead to acidosis, if high levels of concentrates are fed. Concentrates should be introduced very gradually, especially where transition feeding is not practiced.
Rumen pH samples from 12 herds tested by UCD indicated that a quarter of herds may suffer from sub-acute (may not be obvious) acidosis. This often leads to laminitis, reduces feed intake, causes negative energy balance, excess loss of body condition in early lactation, and reduces mounting behaviour.
IT is difficult to put a cost on metabolic diseases, but a Vet Ireland health planning document in 2005 estimated the following average costs per case, including veterinary expenses, loss of milk, reproductive difficulties and, in some cases, replacements.
- Assisted calving €105.
- Milk fever €312.
- Retained afterbirth €392.
- Ketosis €190.
- Displaced abomasum €515.
UCD research indicated that the cost of one mastitis case can be up to €260, including lower yields, milk withdrawal, treatment, price penalties and increased culling.
In 2006, UCD investigated problems in an 80-cow dairy herd in Kerry with an SCC of 400,000 to 500,000.
There were also lameness problems on the farm. Health losses came to €48,400 over a year including production losses, treatment, discarded milk, culling, penalties and loss of bonuses. The cost of bad lameness case is estimated at €312, including loss of production, infertility and culling. (A recent improvement in roadways on the UCD farm improved locomotion and reduced lameness).
Health costs are a major drain on dairy farm profits. But many of our top farmers have a preventative herd health plan in place, which can pay for itself many times over.
Irish dairy herds are now subject to so many diseases that a hit-and-miss, fire brigade vet service is no longer adequate. Many successful farmers with also use the services of a highly trained nutritionist.
High milk yields are not in conflict with high health and fertility status.
