The majority of animals have been housed across the country and some farmers are quite worried about how quickly the forage stocks are disappearing with the elevated dry matter content. This is causing some problems with preservation, leading to high pH in some silage pits of between 4.7 & 5.2 and mould spots.
With forage in high demand and with minimal stocks around the country, diets have been altered to achieve desired performance and to maintain rumen effective fibre.
On dairy farms the aim will be to have a cow calved with no assistance, produce a healthy calf, produce high quantities of milk, stay healthy and start cycling 60 -70 days following calving. A very good approach would be to offer two diets: “far-off dry” and a “close-up dry” diet. Aim to offer 90 MJ per cow per day in the far-off dry period and 120-130 MJ in the close-up dry period. Offer 12-14 kg DM per cow, with correct mineral balance, body condition score and calcium restriction.
The ideal dry period length should be 60 days, extended periods lead to over-conditioned cows with a higher prevalence of metabolic disorders. Blood metabolites such as glucose, NEFA (Non-Esterified Fatty Acids) and BHBA (Beta Hydroxy Butyrate) are taken to check energy balance status via blood sampling.
Increased Risk of Metabolic Disorders
Elevated levels of the above blood metabolites result in a greater incidence of metabolic disorders. Metabolic disorders are interrelated. A cow with a retained placenta has a 5-6 times greater likelihood of developing a clinical case of milk fever. Key factors affecting transition cow management include: sufficient feed space, fresh feed available every 24 hours, good cow comfort and minimise social stress in the dry period. Overall aim should be to minimise calcium intake in the pre-partum period. Grass silage can be quite high in calcium typically in 5kg DM = 30g calcium.
High Straw Inclusion
High straw inclusion can have many benefits (improved rumen health, prevention of fatty liver, controlling energy density of diet), but must be balanced to achieve an overall protein content in the diet of 12-13%. In some cases, dry cows can be offered up to 3-4 kg per head of chopped straw, together with some grass silage, maize meal, soya bean meal and a high phosphorus tailored pre-calver.
In silage with elevated levels of potassium above 2%, offer salt (anionic salt products) to dilute the cation/anion balance. A dry cow will require approximately 40-50 grams of magnesium per day. Typically, magnesium can be offered via powder and through the forage of which is naturally present. Vitamin D will also be important in the role of calcium homeostasis for prevention of milk fever, aim to offer 20,000 iu/day.
To prevent milk fever, magnesium chloride can be also added to the water, calcium binders such as Formaldehyde treated rice bran and zeolite A clays can be used effectively. Do not feed caustic treated wheat to dry cows and rumen buffers that are sodium based as this will have an impact on dietary cation/anion balance. Overall aim to have this DCAD (Dietary Cation – Anion Difference) at -100 to -200 mEq/kg DM. Careful planning in the dry period will help alleviate forage demand, but strategic dietary management will be key to help prevent metabolic disorders.
For any advice or assistance with winter dry cow feeding be sure to contact one of the Connolly’s RED MILLS nutrition team or call into our Agri Super Store in Cillin Hill.
- animal health
- animal nutrition
- Body Condition Scoring
- dry matter
- feeding programme
- transition period
- winter feed