Transition cows are the next generation of milking cows in your herd, so every effort should be made to ensure that they have the best transition into milking and become profitable long-term herd members. Just letting one thing slip under the radar - such as diet, or space allocation - can unknowingly cause costly health problems later on.
Metabolic health problems in fresh cows are most likely to originate from the transition period (3 weeks pre-,to 3 weeks post-calving) and are nearly always nutritional. Metabolic health problems can be very costly to a herd, in both immediate treatment costs, as well as future loss of production. It is important to try not to lose track of transition cow feeding over summer and risk impacting the next lactation - especially when many other jobs need tackling in these busy months!
Milk Fever – True Cost £156/cow
Milk Fever is seen as a major ‘gateway’ disease in fresh cows.It is costly to treat when a cow goes down but often leads to other metabolic health problems. There are the classic clinical signs of low-blood calcium but sub-clinically, it can predispose cows to Ketosis, retained placentas, metritis, displaced abomasum and mastitis. It is thought up to 50% of fresh calvers are in a ‘sub-clinical’ state, which won’t show noticeable symptoms but will mean lower milk yields and susceptibility to other metabolic problems. Calcium is involved in muscle function, so low blood availability will mean the teat ends don’t close as well= mastitis(£79/cow), low rumen function and muscle contractions=risk displaced abomasums(£395/incidence), and intakes will be reduced=risk ketosis(£89/cow).(all figures ref Dr.Esslemont research)
The problem with dry cow diets is that many forage-based ones are high in the cations calcium,potassium and sodium. We need to control the level of these as much as possible in the dry period, so that the cow’s natural hormone system for mobilising body reserves of calcium is effective at calving, when a large volume of calcium is required for colostrum and milk. Often over summer, dry cows are turned out to pasture but the diet is less controlled this way. Grazing can be high in potassium, especially if recently fertilised, and cause havoc with calcium metabolism around calving, predisposing summer calvers to more costly metabolic diseases.
Reducing the risk
We can reduce the risk of metabolic health problems by looking to control the calcium in dry cow diets in two ways.
Firstly, try to reduce the levels of the cations as much as possible and feed a maize silage and straw-based total mixed ration (TMR). If grazing, do so on older pasture that hasn’t been fertilised and ensure that there is adequate protein in the diet for colostrum quality and milk production, from sources such as protected soya.
Secondly, we can supplement the diet with appropriate anions which counteract the effect of potassium, calcium and sodium, when low enough levels cannot be achieved with the feeds available. The aim here is to make the blood more acidic.You may hear the terms DCAB or partial DCAB, which will enable the cow to mobilise body reserves of calcium better.
Magnesium chloride flakes can be added to water sources but make sure all of the water available is supplemented becausecows will try to avoid the bitter taste.Chlorides are more effective than any sulphate-form anions.
There are also specially-designed dry cow feeds such as Wynnstay’s Prepare 80:20 Nuts which are a partial Dietary Cation-Anion Balance (DCAB) approach.They contain Vitamin E for antioxidant properties and protected choline, to enhance liver function and metabolism.
Compound feed options work well over summer too, especially when feeding 3-4 kg/head at old pasture with mixed silage and straw to deliver the right balance of minerals. This reduces the risk of milk fever and other costly metabolic health problems over summer.