Calving at CAFRE Hill Farm, Glenwherry
Dr Norman Weatherup, Beef Technologist, CAFRE and William Warwick, CAFRE Farm Manager
Background
The hill farm currently supports a 100 cow suckler herd generating its own replacements from a three-breed rotational breeding programme. The herd originally was split in two parts with 25 cows and heifers calving in February (that is, before lambing) and 75 cows and heifers calving in May/June (after lambing). However as shown in Figure 1, the reality was that the two parts had merged resulting in a six month continuous calving period.
Compact calving was identified as a management tool to reduce labour requirement, to help identify cows with poorer fertility and to simplify routine tasks such as vaccination and weaning. Achieving compact calving requires time, planning and management effort. Discipline is also required to ensure the situation does not revert!
Figure 1: Number of cows calved throughout the calving period in 2006 and 2009
So how have we moved from calving cows for six months in 2006 to potentially little over two months in 2010? The progressively shorter calving periods are shown in Table 1.
Table 1: Calving periods from 2006 to 2010 (projected).
| First calf born | Last calf born | Calving period (days) | |
|---|---|---|---|
| 2006 | 15 January | 24 July | 190 |
| 2007 | 20 January | 21 July | 182 |
| 2008 | 15 February | 22 July | 158 |
| 2009 | 18 April | 8 July | 81 |
| 2010 (projected) |
1 May (Synchronised heifers start 20 April) |
3 July | 63 |
In 2008 and 2009 the bulling period was significantly reduced. Despite this, 94 percent of cows were pregnancy diagnosed in calf in both years. In 2009, 90 percent of cows calved in the first six weeks (two cycles).
A number of steps were necessary to obtain the new calving profile as shown in Table 1.
Table 1: Steps to more compact calving May – June at Glenwherry
| 2007-present | The desired calving period was selected (first of May onwards). |
| Bulls entry to early calving herd delayed by 1 month. | |
| Bulls were put in with main herd as normal BUT REMOVED AFTER 75 DAYS. | |
18-20 heifers synchronised and AI’d to calve down 2-3 weeks before the desired calving period. |
|
| 2008-present | Bulls ran with the herd for the desired mating period and the remaining early calving cows were allowed to slip |
| Cows were pregnancy diagnosed and those empty culled! Herd size remained the same from 2006-2009, 6% of cows each year were culled for infertility and all cows should calve down within 63 days in 2010 |
Excluding the cows which were managed to deliver a more compact calving pattern, the calving index for the herd was 362 days in 2008-2009.
Compact calving is a tool that adds to the bottom line and simplifies management particularly where cows calve at grass. It also highlights poor fertility cows for culling as these animals do not produce a calf within the target calving period. A more rigorous culling policy is feasible with present attractive prices for finished cull beef cows helping to keep down replacement cost while improving herd efficiency.
William Warwick and Dr Norman Weatherup review calving records
