Wednesday, 2 December 2009

December a Crucial Month for Spring Calving Dairy Cows in UK

Dry cow feeding in December is really important. For February calvers December is make or break month. Young stock have target weights to achieve & most spring calving dairy cows need to gain condition.

Today at Stafford I saw a group of extremely well grown heifers outwintering on Swift forage crop. Not only were they well grown but they were in great condition as well. At last weighing these heifers were on target LWTs. Makes a huge difference when you actually know the weights. Too few farmer weigh the young stock.

NZ targets at 21months (630 days) are Friesian 475kgs, XBred 420kgs & Jersey 365kgs LWT. For 24month (730 days) targets add 60-110kgs. The 10 week calf target is 100kgs....these calves need at least 17MJ/day for maintenance alone.

So lets look at the feed requirements for heifers....a 212kg LWT heifer (10months of age) requires 30MJ/day for maintenance. A 440 kg LWT Heifer (22 months) requires 46MJ/day for maintenance. To acheive winter weight gains above 0.5 kgs/heifer/day the 22month heifer needs approx 9kgsDM/day...(2% of LWT).....whereas the younger heifer (10months) requires nearly 5kgsDM/day(2.2% LWT). This assumes top quality feed.

Dry Cows need very good feeding in December if they are to calve in good calving condition. A mature aged 500kg cow has a maintenance requirement of 54MJ-60MJ/day. To gain a Condition Score (NZ) in a month requires at least an additional 55MJ/day above maintenance. Remember in the last 30-40 days before calving you can't expect to put extra condition on a cow that is about to calve.

I am working with three keen Discussion Group members to both monitor Cow Condition & to develop a decision making tool that combines Cow Condition Score with Calving Date information.
To date there are some interesting findings.....most cows continue to lose condition in late lactation even with very good feeding (this maybe genetic??)...........Cows initially lose additional condition when they are dried off (possibly change of diet??).......Dry Cows need to be fed very well to put on 1kg LWT/day....its a tough target!......and finally maybe heifers need extra time compared to mature aged cows to gain condition.

Can dry cows gain the necessary condition when outwintered on forage crops......the jury is out!

Lastly some interesting Irish work showed that dry cows of high genetic merit could gain weight faster than 1kg LWT per day.......mind you they tended to lose it more easily in late lactation too.

Achieving good cow condition at calving is key to good milk production & better fertility results. A lot hinges on a good December.

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