Having enough of the farm grazed to maximise new growth and having enough grass to feed cows is the regular balancing act on most dairy farms for the last two weeks of March.

Growth rates for February and March are pretty consistent from year to year. You can’t depend on growth rates much greater than 5kg per day in February and not greater than 15kg per day in March. It means in the main you are depending on October- and November-grown grass to feed freshly calved cows.

This often makes farmers wonder why they should bother to spread early nitrogen and many farmers claim victory, a cost saving, over the early spreaders by comparing their February and March growth rates.

However, the growth on ungrazed paddocks spread with urea and the recovery rate of grazed paddocks is much better on paddocks that get nitrogen. Every day’s growth is vital at this time of the year, so you need to feed grass to maximise that growth rate.

The dry and cold weather of the last week means graze-out has been top class on most farms, including the Kilkenny farm. However, the harsh cold easterly winds have given the tips of new grass a purple tinge.

With the new paddock in the rotation this year, there are now 120ha available for first-round grazing. So far, 84ha have been grazed (70%) and there is 36ha left for the first round (Figure 2). The area to be closed for silage will probably get a second graze before closing. The farm cover is measured weekly and this week (Figure 3) the cover is down to 500kg (220kg/LU). Growth rates have been 5, 10, 18 and 15kg respectively for the last four weeks.

Farm cover

Having the figure for area grazed and the average farm cover will give you a good handle on the grass situation. Some farmers work with the area grazed figure only, but this isn’t good enough – you need both figures. It’s not much good having 30% of the farm left to graze and no grass cover on it.

Growth is being pushed along in Kilkenny – a half-bag of urea went out 2 February and three-quarters of a bag of urea on 10 March. Stocking rate is 2.25 cows/ha and once first cut area is closed (mid-April onwards) stocking rate will rise to over 4 cows/ha so demand will be high during the high peak grass growth period.

Given the results of the area grazed and the farm cover last week, farm staff decided to start feeding quality round baled silage over last weekend and 3kg of meal per cow. This was part of the overall plan once at least 60% had been grazed. There are plenty of quality round bales in stock. So far this year, 3kg of meal per day on average has been fed per cow.

February and early March grazing has been much easier this year in Kilkenny compared to last year and shows the difference a year can make. Last year, 324mm of rain was measured from 1 February to mid-March – this year it was 107mm, only 30% of last year’s volume.

Milk quality

The silage effect on milk yield so far has been minimal. As you can see from Figure 1, milk protein and fat percentages have been slipping as per normal following the high figures post-calving. Overall milk supplied year to date is actually back compared to 2014 because there have been about 20 fewer cows calved all through the first six weeks of calving and more milk has been fed to calves this year. Somatic cell count is 142,000 cells/ml.

Milk recording

The first herd milk recording for 2015 was completed last week to get a good handle of somatic cell count for all calved cows. Some farmers prefer to wait until all cows are calved but there are big advantages to an early recording before any milk quality issues get established.

The six-week calving rate for the 334 due to calve down was established at 76% last week (approximately 250 calving in six weeks). There are about 60 cows left to calve in total. There were no calves born by the end of January this year and there were 191 calved for the end of February.

When you look back over the insemination results, there was a very bad pregnancy rate to one of the AI sires (ZBT with 20% conception rate) and too many straws of this one bull were used (15%). You take a big risk when using too much of any one AI sire and a slightly slower calving rate and longer tail in calving are some of the consequences. Our figures show the rest of the AI sires used came in about normal, with a pregnancy rate of close to 50%.

As we reported previously (Spring AI Focus supplement), calving ease has also been an issue with some of the genomic bulls used on the maiden heifers. It is a fine line trying to establish whether it is feeding management or a sire effect, but all our indications suggest it was a sire effect. It will be interesting to watch ICBF figures.

Management will be very careful on what genomic sires to select for maiden heifers this year. There were two C sections in heifers and both cows will probably not milk this year.

In other herd health issues, the farm also had nine cases of milk fever from 250 calvings, which is too high, and much higher than previous years in Kilkenny. Magnesium has been increased through the water. The cows will be vaccinated for BVD and Lepto this week.

Calves

Slightly more bull calves (53:47 ratio) so far this year. There are 72 heifer calves gone to the contract-rearing farm and about 70 bull calves have been sold.

So far this year 18 calves (7%) have been lost at birth or within the first 14 days, which is about the national average, but slightly high compared to the last five years in Kilkenny.