Reviewing replacement heifers in Down

A mid-season review of heifer rearing was carried out on Stephen Wallace’s farm near Seaforde, Co Down, last week.

There are 47 Holstein Friesian heifers in the main group of replacements which will be due for insemination in December 2019. This group has an average age of nine months and dates of birth range from 3 September 2018 to 23 December 2018.

The group currently has an average weight of 264kg. This represents a daily liveweight gain of 0.85kg from birth and 1.04kg since their last weighing at turnout on 28 March 2019.

The main lesson from last week’s exercise is that the heifers are performing well and are on target to hit 60% of mature bodyweight at breeding. For Stephen’s herd, this equates to 360-400kg by the start of December.

There are around 130 days to go until the start of breeding and the average heifer with a current bodyweight of 264kg needs to put on 96kg by then to reach the lower breeding weight target of 360kg. This equates to an easily achievable daily liveweight gain of 0.76kg.

The main group of 47 heifers is in a simple four-paddock grazing rotation and they are being fed concentrates in troughs at 1kg/head/day. The heifers were on 3kg/head/day of concentrates earlier in the grazing season which led to the high daily liveweight gain seen since turnout.

If Stephen kept concentrate feeding levels up and heifers continued to gain over 1kg of liveweight per day, then breeding could take place in under 100 days for the average heifer.

Dairylink Ireland adviser Aidan Cushnahan said that this would equate to an average age at first calving of 22 months and research shows that lifetime performance from younger-calving heifers tends to be better.

However, heifers would start calving around a month before the main herd begins in September.

Compact

One of Stephen’s key objectives from participation in the Dairylink programme is to establish a tighter autumn calving profile. At present, cows are calving from September to late April.

Stephen wants a compact calving block so that he has a more seasonal work pattern, particularly with calving, calf-rearing and breeding. It will also allow herd fertility to improve as cows that are slow to get in-calf will leave the herd and he will be able to capitalise on early season grazing as more cows will be over peak lactation and settled in calf by the spring.

The plan with the heifers is to split the main group into two with the majority of heifers going on to a grass-only diet and lighter ones remaining on 1-2kg/head/day of concentrates. This should allow the overall group to become more uniform and will mean heifers will not be calving out of season.

There is another batch of 20 Holstein Friesian heifer calves on the Wallace farm which are later born, mostly in January and February 2019. These heifers have not been weighed yet but are clearly lighter than the main September- to December-born group.

Stephen plans to weigh this group in the next few days and he will put the lighter heifers from the main group along with them. If he needs extra replacements for next year, he could keep January 2019-born heifers and delay breeding for them until February 2020 to have them calving from November 2020 onwards.

However, he doesn’t want to keep any February 2019-born heifers as they will likely be too far out of sync with the rest of the main group of replacements. These later-born calves will be sold at some point, either as maiden or in-calf heifers for a spring-calving system.

Second-cut silage was ensiled on the Wallace farm on 5 July and Stephen is pleased with the bulk and condition of the crop. It is a stark contrast to this time last year, when drought conditions meant second cuts were extremely light in some parts of Co Down.

Stephen got fertiliser out after second-cut but there was a delay in getting slurry spread as contractors were busy at silage. Grass covers had come back well when slurry was going out two weeks later, so a dribble bar was used instead of a splash plate to avoid contaminating the sward.

Slurry stores are almost empty on the Wallace farm now, which takes the pressure off having to spread later in the season and means the benefit of the slurry will be seen in grass growth.

There were 25 acres of surplus grass from the milking platform mowed down for bales on Monday. Stephen is measuring covers on the grazing block weekly and, similar to weighing heifers periodically, decision-making is based on quantified information.

Drying off

Drying off begins in earnest from this week onwards with first cows due to calve in mid-September ready for an eight-week dry period. All cows get dry cow tubes and teat sealers, as well as treated for fluke, worms and a vaccination for rotavirus.

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