Dairy cow fertility underpins the viability and productivity of our spring calving farm system. We aim to achieve:
- > 78% 6-week in-calf rate
- < 10% not-in-calf rate
- < 70 day calving period
Owl Farm uses all AB (artificial breeding) for mating; in 2019 we started using sexed semen on our top BW (Breeding Worth) cows and Wagyu semen to provide bull and heifer calves for a First Light contract. This was extended in the 2020 and 2021 matings to include heifer synchrony and sexed semen to further reduce the number of bobby calves produced.
Our 2021 Planned Start of Mating (PSM) was the 22nd September, for a Planned Start of Calving (PSC) of the 1st July 2022. Efforts to improve reproductive performance this year include:
- Cows are dried off on BCS targets relative to calving date
- All cows are metri-checked and 25 cows (6%) treated
- Pre-mating heats recorded and CIDR programme used on 28 non-cycling cows (6.8% of the herd)
- PG (prostaglandin) programme used on 100 cows that cycled in the week prior to PSM
- Heat detection aids include LIC Heat Patch Plus and tail paint
KEY STATISTICS from our Fertility Focus Report for 2020-21 season:
65% 6-week in-calf rate
14% not-in-calf rate
90-day mating duration
88% 3-week submission rate
47% conception rate
In the 2020-21 season we achieved a 6-week in-calf rate of 65% which is below the industry target (78%), and 9% below our last two previous seasons. While heat detection appeared to be slightly lower than target, it was conception rate which has had the biggest impact on the final results.
Analysis of the data with LIC and Cambridge Vets showed:
- Planned Start of Mating (PSM) was moved forward by one week to return to our normal PSC of 4th July (2021)
- Reduced performance of two-year-olds who achieved 67% 6-week in-calf vs 81% last season. This group returned to the farm in mid-April at 416 kg due to 52% of them being under their target weight; they gained 39 kg to reach 455 kg on 3rd June (29% underweight). These heifers calved at BCS 5.8, were BCS 4.9 at PSM and continued to drop to BCS 4.7 by mid-November. We did not use OAD for these younger cows like we did in previous years due to their good BCS, high milk production and enough feed being available.
- Evidence of early foetal loss, because the herd test PD at 3 weeks showed 50% of cows were in-calf.
- Improved in-calf rate at the end of mating between weeks 9 and 11 (late November and early December).
- Cows peaked higher and longer than last season, with a significant drop in production from late October. We also experienced a significant change in feed quantity and quality in late October/early November. Average Pasture Cover (APC) went from 2033 kg DM/ha to 2495 kg DM/ha within two weeks and production dropped from 2.1 kg MS/cow to 1.7 kg MS/cow. Mixed Age cows calved at BCS 5.6, were BCS 4.9 at PSC and continued to drop to BCS 4.5 by mid-November.
You can read all the details of the breeding programme here.