Transition Management of Cows

For many farmers when we say 'cow transition' they immediately think about the dietary change from crop to grass when the cows come home. In fact transition is a whole lot bigger than this.

In a matter of days between the period before and after calving, a cow's:

• energy requirements almost double
• she starts making milk
• about 30-40 grams of calcium are lost through the milk daily
• she has a greater demand for blood glucose, which requires a change in metabolism

To accomodate these changes well, the cows must:

• eat more
• increase the size of the intestines (absorptive area)
• increase the size of the liver (to meet demands of increased metabolism and drive appetite)
• increase the amount of mammary tissue
• mobilise bone calcium (70% of calcium in the colostrum comes from the skeleton!)
• increase dietary absorption of calcium through the gut
• mobilise body tissues for extra energy (but not too much!)

When cows are transitioned poorly, they are :

• more prone to ketosis
• more prone to mastitis
• more prone to milk fever
• more prone to metritis
• will not peak as high or as early in milk production
• lose more weight post-calving
• have a poorer reproductive performance

So to get optimal results from a cow this season, she needs to reach a BCS of 5.0-5.5 by 3-4 weeks before she calves, ideally be on a slight negative energy balance during the last 3-4 weeks of gestation (this will pre-condition the liver to the post calving demands), have increased feed quality over the last few days before she calves (as voluntary dry matter intakes tend to drop), be supplemented with magnesium for at least 3-4 weeks before she calves, be on at least 70% of the post-calving diet for 7-10 days before she calves and finally be offered high quality and ab-lib feeding immediately after calving.

By definition, the transition period in a cow is the period between 3 weeks pre-calve and 3 weeks post-calve. Look after them well over this time - it will make the difference between an okay season and a great one.

Calf Health and Management

We are more and more aware of the impact our heifers will have on the future success of our herd. Getting valuable replacement heifers off on the right foot in the pre-weaning period is a crucial step in bringing in top quality,  well grown heifers as two year olds.

The Veterinary Centre can offer a full range of calf health and management advice.

Dairy veterinarian and veteran calf rearer Nicola Neal can assist with the set up and design pf your calf shed systems and management. Nicola completed a Masters paper in "Calf Health, Disease and Management" last year and is keen to apply some practical on farm knowledge, along with the latest scientific advice. This service is tailored to suit the individual farm and could include on farm training of calf rearers', developing quality assurance systems wen you can not be there to supervise, developing calf health plans and making the most of facilities.

Do not wait for a problem to develop in the third week of calving when you have not got the time to deal with it, call now to book a time to review you calf shed systems.

Setting Your Herd Up for Success

If significant BCS gain is required over the dry period be realistic about what you need to feed your cows. As little body condition can be gained in the last month of gestation, feed maximally in the month of June to try and maximise this gain.

A cow putting on 1 BCS in the month of June will require about 7kg DM/day above maintenance and pregnancy requirements compared to a cow already at target.

• For every BCS below a 5 at point of calving, cows will tend to produce 12-20kg of MS less for the season.
• For every BCS below a 5 at point of calving cows will tend to take an additional 10 days to resume cycling.
• Cows which do not have a pre-mate heat will have 10% lower conception rates when finally mated.
• The target BCS for an individual cow at point of calving is 5.0-5.5. This is an extremely good looking cow. Her pin bones are no longer visible (at all!), the rump is filled in, the hips are rounded, the spine is not visible (at all!), the short ribs are rounded and the long ribs are not visible (at all!).
• It is thought that a large proportion of cows in New Zealand calve below target BCS.

Nitrate Toxicity Alert

Brassicas (Kale, Chou, Rape, Turnips and Swedes), fodderbeet, Italian ryegrass and oats can all produce nitrate toxicity. Of this group, rape is the most notorious - winter rape crops continue to gain popularity in this area for heifer grazing.

Before introducing animals to crop this June, we urge that it be tested first.  Nitrate test kits can be purchased from any of our clinics, representing a cheap investment. Alternatively bring in samples to be tested by our staff.

Targetting BCS 5.0 at calving

It is a well known industry target that cows should be a minimum of 4.5 at dry off at the end of May - preferably 4.7, so the cows only have to gain 0.5 of a BCS over winter, to reach the desired target of 5.0 to 5.5 condition score at the point of calving. Cows at BCS of 3.5 should be dried off now. Cows less than 3.5 are unlikely to get to BCS 5.0 by calving even if maximally fed. Remember some supplementary feeds are better at partitioning to BCS than other - maize, barley (cereals) and as we see on a lot of farms now, fodderbeet.

Ideally cow wintering groups would be made up according to calving date  - however if your herd BCS is wide, as is commonly the case, it is suggested to winter the bottom portion of the herd separately and feed these preferentially. You may wish to consider making up wintering groups based on a combination of both BCS and calving date. Our practice can offer a service where we can individually BCS cows and match these with their predicted calving dates. Cows are then split into early calving skinnies, early calving fats, late calving fats etc. Sheds fitted with Protrak makes drafting simple! Also with the current wet weather, the number of lame cows on some farms is increasing, so decisions on dry off and BCS may be brought forward to allow for developing lameness issues.