Mating sheep on red clover swards

Four farmers and researchers are investigating whether the inclusion of red clover in swards impacts the fertility of grazing ewes.

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Field Lab Timeline

    6/14/2021 11:00:00 PM
  • Kick off meeting

    Kick off meeting
  • 8/14/2021 11:00:00 PM
  • Field lab confirmed

    Field lab confirmed
  • 9/19/2021 11:00:00 PM
  • Farm setups confirmed

    Farm setups confirmed
  • 10/14/2021 11:00:00 PM
  • Pre-tupping sward assessments

    Pre-tupping sward assessments
  • 11/15/2021 12:00:00 AM
  • Rams introduced & sward assessments

    Rams introduced & sward assessments
  • 12/15/2021 12:00:00 AM
  • End of mating period - sward assessments

    End of mating period - sward assessments
  • 1/15/2022 12:00:00 AM
  • Ewes scanned & recorded for fertility

    Ewes scanned & recorded for fertility
  • 2/15/2022 12:00:00 AM
  • Analysis & results

    Analysis & results
  • 3/15/2022 12:00:00 AM
  • Results meeting online

    Results meeting online
  • 5/31/2022 11:00:00 PM
  • Farm walk & results day

    Farm walk & results day
  • 6/30/2022 11:00:00 PM
  • Final report published

    Final report published
For further information hover over the above milestone marks
  • Discussion

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  • Achievements

    September 2021

    Trial design

    The triallists are 4 farmers who all have a flock of at least 100 breeding ewes and swards containing red clover in place on their farms.

    The ewes selected for the field lab trial will be randomly split into two ‘sub-flocks’ (of at least 50 ewes each) taking account of variation in age, breed and past performance. One sub flock will graze the sward containing red clover for at least 3 weeks pre mating and for the duration of the mating period. The control sub-flock will be grazed on swards which do not contain red clover. At the end of the mating period the sub-flocks will be merged (if possible) to ensure management for the remainder of the ewe’s pregnancy is the same.

    Information on fields and swards in the field lab will be collected during the trial set-up. This will include soil type, establishment date, seed mixture and varieties sown. During the set-up visit previous fertility performance data and details of normal grazing policy will also be gathered.

    During the field lab the quantity of red clover in the sward needs to be assessed to establish the % of red clover contained within the sward prior to and during the grazing period. The participants felt it would be better for this to be carried out by the coordinator to ensure timeliness and standardisation of assessment. The clover content will be assessed using quadrants in the same location. 3 weeks before the start of the mating season a sample of the sward will sent for lab analysis for dry matter and nutritional content.

    The farmers will record treatment of the sward, stocking rate, length of time grazed prior to tupping and to record the scanning results for each sub flock separately.

    Once the field lab trial is complete the results will be collated and analysed to determine if mating sheep on red clover swards influences fertility. Whilst phyto-oestrogen assessments will be essential for formal industry advice to change, this field lab could help access further Defra funding in the future.

    Milestone: Farm setups confirmed

    September 2021

    Field lab context - red clover research

    Red clover contains phyto-oestrogens which mimic oestrogen. Historic research conducted on pure clover swards in the 1960’s & 70’s in the southern hemisphere established a negative effect on ewe fertility. Industry advisers, vets and grassland consultants have to recommend that breeding ewes are not grazed on leys containing red clover prior to or during mating or for periods of longer than a few months. Whilst this guidance remains unchallenged the utilisation of swards containing red clover is restricted to non-breeding livestock for significant parts of the grazing season. It limits practical utilization of legumes and puts sheep farmers off including red clover in a significant proportion of their grass leys.

    Historic research was mostly conducted on pure red clover swards, but red clover is rarely grown as a monoculture in the UK. Legumes are mostly included at 20-30% of the seed mix with red clover as low as 10% inclusion. The remainder of the sward comprises grasses and sometimes herbs/wildflowers. Modern varieties of red clover have also been developed with lower levels of phyto-oestrogens, yet no practical research has been conducted to establish whether these new varieties are ‘safe’ to graze during mating.

    However, some of the farmers in this field lab are already grazing multi species grassland swards containing red clover, prior to and during mating without reducing ewe fertility but no farm-based research evidence or thorough investigative studies of on farm practice have been carried out to support a change in the guidance. A review conducted by IBERS (2011) into the effects of legumes on ewe & cow fertility concluded that more research was required in 3 key areas, including grazing strategies around mating “to effectively develop the current guidelines on use of forage use legumes without any detrimental effects on livestock fertility."

    Milestone: Field lab confirmed

    August 2021

    Field lab context - importance of red clover

    Red clover is becoming increasingly popular for a variety of reasons. It is a crucial component of the GS4 mix (legume and herb-rich swards) - one of the most popular stewardship options for arable or grassland farmers, where a minimum of 10% red clover coverage is required. Red clover's benefits include:

    - High yielding
    - Drought resilient
    - Nitrogen fixer - reduces use of inorganic nitrogen
    - High protein content
    - Nectar rich (for pollinators) - in GS4 mix, the sward has to be left to rest for 5 weeks in the summer to assist pollination

    Within herbal ley mixes, red clover will be prevalent than the other species in the mix in the autumn, which is also the mating season. Farmers require confidence to graze breeding stock onto clover during this time and are otherwise limited on how much land they can put down to multi-species swards containing red clover. If no negative effect on ewe fertility is found, farmers could expand how much land is put down to legume and herb rich swards, which would generate additional sources of income and boost farm sustainability.

    Milestone: Field lab confirmed

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