Farm Ireland
Independent.ie

Wednesday 20 September 2017

Our focus now has to be achieving a strong BCS when cows are dried off

Dr Dan Ryan

The past month has put icing on the cake for dairy farmers in grass-based milk production systems. The memories of a harsh summer in 2012 and spring of 2013 have now been largely overcome by an excellent summer grazing season in 2013.

The farming community has definitely learned lessons from the past 18 months.

Farmers have taken the opportunity to harvest extra silage where available because of poor first cuts. The weather has lent itself perfectly to the conservation of excellent silage, barley, wheat and the prospects of a bumper crop of maize.

With spring breeding programmes now complete, it is time to evaluate what stock you will have for calving in 2014. It is essential to scan those cows still not confirmed pregnant that have been served at least 30 days.

Embryonic mortality will be significant up to day 35 of pregnancy. Less than 5pc of pregnancies will be lost beyond day 35, which is primarily accounted for by losses of twin pregnancies, followed by cases of neospora and salmonella in later stages of pregnancy.

With good grazing conditions looking set to continue into the autumn, it is vital that farmers move to reduce the risk of superlevy fines. Some plan to put their cows on once-a-day milking, which will reduce milk output whilst maintaining output of milk solids.

However, care has to be taken that SCC is not increased significantly.

In my opinion, one should now consider the number of cows needed to fill your milk quota in 2014/2015 quota year. Identify those in-calf heifers and cows which will calve before the end of April 2014. If this number meets your quota, then you should evaluate your winter forage requirement making an allowance for a longer wintering period.

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Most farmers now accept that extra silage in the pit is no longer an "inventory cost" and safer than money in the bank.

It is essential to measure your stocks of forage now and consult your advisor if assistance is needed. This will allow you to target the best time to sell empty cows or keep late calvers in 2014. Empty cows may produce cheap milk until the close of the milking season, but at the expense of the breeding programme for the in-calf herd in 2014.

This brings me to the kernel of our management practices at this time of year. Our focus has to be one of achieving a body condition score (BCS) of 3-3.5 at the time cows are dried off.

The big risk at this time of year is that the production of cheap milk off grazed grass comes at the cost of a loss of body condition.

High faeces passage rates (scouring) associated with either lush grass or heavy infestation of fluke have to be avoided as it will result in BCS loss. Tight grazing to either extend the rotation or refusing to top grass are unacceptable practices if BCS is compromised.

The target BCS at the time of drying off also needs to be maintained until cows calve. Attempting to gain BCS when cows are within two months of calving is the wrong approach to next year's breeding programme. It may be difficult to comprehend that management practices now can have an impact on next year's breeding programme.

However, research data clearly shows that cows which maintain an ideal BCS through the final two months of pregnancy have fewer cases of retained after-births, calving difficulty and metabolic diseases around the time of calving, which in turn has been associated with improved subsequent reproductive performance.

Finally, we have just completed a study involving more than 1,000 dairy cows, showing that adverse events either during the dry cow period or around calving were associated with significantly higher SCC in milk harvested between 13 and 22 days post-calving.

The cows in this study were grouped into healthy and unhealthy groups on the basis of a scan of the womb, with 35pc of the cows classified as unhealthy and having significantly higher SCC.

These results highlight how milk processability and, ultimately, milk prices may in the future be dictated by management practices in late lactation prior to drying off.

It proves that it is essential to have healthy cows at all stages of the production cycle to produce healthy milk that will hopefully lead to healthy profits.

Dr Dan Ryan is a cow fertility expert and can be contacted at www.CowsDNA.com

Irish Independent