Managing Autumn Calving Cows
The advent of autumn calving is now a reality for many dairy farmers, either as a split calving pattern formed from the need to give a home to some empty cows. or as a response to changing farm systems where 100% autumn calving is desired. Whatever the reason for autumn calving on your farm, there are a number of practical ration balancing tips that can really help set your girls up for a productive season.
RATION BALANCING TIPS
Dry cows and transition feeding; it has been a tough summer for many in the top half of the North Island, meaning BCS may not be ideal at dry off. We suggest that you don’t attempt to gain 1 BCS during the first 4 weeks of the dry period as this can lead to greater insulin resistance post calving (which means potentially greater BCS losses post-calving). Do feed to the nutrient requirements of your cows as they move towards the day of calving, as the unborn calf places increasing nutrient demands on mum. Most cows will require in the range of 120-145 MJME daily, so don’t be afraid to ramp up the kg’s of dry matter.
We still need to do all that we can to prevent milk fever and the metabolic diseases associated with it. While many will know from experience that there are often fewer incidences of milk fever when calving in autumn, this is primarily due to lower pasture intake, it still occurs both clinically and sub-clinically. Implementing a high magnesium, negative DCAD ration will support blood calcium outcomes. There have been some very pleasing results coming from feeding a bio-active form of Vitamin D in New Zealand of recent times This is in association with negative DCAD, high magnesium rations, but also allows for higher levels of calcium to be offered. Contact your local DNS for more information.
Meeting protein requirements is critical stimulating DMI in late gestation dry cows and recent research is also showing benefits in “firing up” the mammary gland for a productive season (Appuhamy et al., J Nutr. 2011). If you have low pasture allocation and the summer has left you with lower pasture quality and you plan to feed maize silage, you will need to add a high quality protein supplement. Many suggest PKE as a protein supplement, however the quality of protein (amino acids) in PKE alone will be inadequate to balance the ration for a highly productive fresh cow. Your local Dairy Nutrition Specialist can offer you further assistance.
Achieving high peaks (>2.2kg MS daily) from fresh autumn calving cows consuming high levels of conserved forage can be quite challenging. Cows will often “tap out” on intake due to high forage NDF consumption before they have consumed adequate nutrient to support high levels of milk solids output. To push higher, you will need to change the forage to concentrate ratio of the ration, resulting in an improved forage NDF : NFC (Non-Fiber Carbohydrate) ratio.
Tables 1 and 2 below highlight how this could possibly play out;
Ration 1 Ration 2 Pasture 6kg DM 6kg DM Maize silage 5kg DM 5kg DM Pasture silage 3kg DM 3kg DM PKE 2kg DM Pellets 2kg DM 5kg DM Totals: 18kg DM 19kg DM MJME 193 MJME 218 MJME Forage NDF : NFC 1.1 0.8 Possible kg MS daily 2.21 kg MS 2.46 kg MS MOPFC $9.32 per cow daily $9.38 per cow daily
Ration A Ration B Pasture 6kg DM 6kg DM Pasture silage 5kg DM 5kg DM PKE 3kg DM 3kg DM Pellets 2kg DM 5kg DM Totals: 16kg DM 19kg DM MJME 170 MJME 207 MJME Forage NDF : NFC 1.1 0.8 Possible kg MS daily 1.71 kg MS 2.15 kg MS MOPFC $6.56 per cow daily $7.08 per cow daily
As pasture availability increases, PKE and pasture silage can be reduced accordingly to allow for greater pasture intake. NB., MOPFC may sometimes take a hit for a short period of time in order set your herd up for the season and reduce BCS losses.
Balancing macro and micro minerals is essential to sustaining positive animal health outcomes. In tables 1 and 2, the pellets used include limeflour, di-calcium phosphate, magnesium oxide and magnesium sulphate to further reduce the incidence metabolic issues. Maize silage tends to be low in macro minerals and while PKE does test out better in the lab on this front, anecdotally we are observing phosphorus deficiencies on a more regular basis when both of these feeds form a major part of fresh cow rations. Macro minerals are inexpensive, so go hard out to balance them. Pelletised feeds provide a great vehicle for supplementing minerals to your herd with accurate distribution to every cow.
Winter milk pricing is also quite an incentive to push productivity along. With contracted winter milk now attracting up to a $3.50/kg MS premium for June and $2.85/kg MS during the shoulder periods in May and July, the financial opportunity can also be utilised to the advantage of your business.
For further support with balancing rations for your autumn calving cows, contact your local Dairy Nutrition Specialist.