Sustainable out wintering of beef cattle on straw pads

Project number:                    72606

Lead contractor:                   ADAS UK Ltd

Partners:                                  Environment Agency

Start & end date:                   October 2012 – September 2014  (extended to November 2014)

 

The Problem:

Well-designed and managed wood chip pads for out-wintering cattle can improve animal health and welfare, reduce poaching damage and reduce labour and building costs.  Recent LINK funded research has confirmed the suitability of wood chip pads for certain regions of England.  However, the quantity of readily available straw and lower relative rainfall on the eastern side of the country may render straw-bed corrals (SBCs) a more suitable alternative.  A straw-bed corral (SBC) is an un-lined, un-roofed, deeply bedded enclosure, built on a field site. They are normally temporary in nature, built before the onset of winter with the accumulated FYM removed and spread and / or temporarily stored on a field site once the livestock have been removed.

SBCs would reduce/eliminate requirement for slurry storage, therefore be of particular interest for Nitrate Vulnerable Zone compliance.  Further study is required on their operation and pollution risk to advise farmers on their use whilst minimising environmental effects.

 

Project Aims:

  • To quantify the distribution of nutrients through the soil profile under straw-bedded corrals
  • To derive nitrogen (N) and phosphorus (P) balances, using excretal outputs, N and P content of the accumulated soiled bedding, measured nitrate leaching losses and ammonia loss estimates
  • To review practical experience (good and bad) of cattle wintering on straw-bedded corrals on commercial farms where these can be located
  • To draft recommendations on straw-bedded corral design and management based on the findings of the research.

Deliverables

Recommendations were made on straw pad design and management based on the findings of the research for a Better Returns Plus publication.

 

Approach:

Detailed measurements were taken on two commercial straw pads on one farm representative of typical practice in Eastern England over two winter seasons (2012/13 and 2013/14). Observations included:

(i) Estimation of potential drainage via the IRRIGUIDE water balance model for the site;

(ii) Drainage water below each straw pad, and from an adjacent unstocked, ‘control’ area, were sampled using porous ceramic sampling cups (10 per pad). Samples were collected every 2 weeks during the winter or after 25 mm of drainage. Samples were analysed for nitrate- and ammonium-N;

(iii) Soil samples (0-90cm) were taken at the end of the production cycle and analysed for nitrate-N, ammonium-N, P and K to assess the depth to which effluent had infiltrated the soil;

(iv) Records were kept of animal numbers and duration on the pads, quantities of straw used and any removals of soiled bedding (i.e. tonnages, with samples taken for analysis). Nutrient inputs on each straw pad were calculated from standard figures for manure production and nutrient contents of excreta (Cottrill and Smith, 2010). Samples of soiled bedding were analysed for total N and P, ammonium-N, nitrate-N and bulk density of the bedding was assessed, to quantify the nutrient loading on each straw pad. The combined data allowed N and P balance estimates to be made across the pads.

 

Results:

A review was undertaken of the construction, management and distribution of straw pads used for beef cattle in England.  Of the 15 pads identified, detailed information was collected from 9 farms. The total number of cattle kept on the pads at anyone time varied between the farms from approximately 50 up to 2500. All of the farms were positive about the health of the cattle kept on the pads. The majority of farms thought the cattle were as clean outside on the pads as they would have been in a roofed straw yard. None of the farms reported any foot problems or lameness associated with the pads, and 5 farms gave the opinion that cattle kept on straw pads were healthier due to reduced risk of respiratory problems or pneumonia.

Measurements were carried out on two commercial outdoor pads on the same farm located in the East of England, one bedded with straw the other one with waste woodshavings.

The measurements included observations of pad condition and livestock performance, drainage water sampling and calculation of over-winter drainage and nitrogen (N) leaching from under the pads.

Nitrate-N and ammonia-N concentrations in drainage water from both the straw and wood-shavings pads were very high (approximately 60-450 mg/l NO3-N and approximately 5-35 mg/l NH4-N), indicating that any effluent draining into the soil from these pads represented a high risk of diffuse N pollution.

In 2012/13 for the period when the cattle were on the pads (1st October 2012 to mid-March 2013), the estimated drainage volume was 20 mm and 96 kg/ha N was lost via leaching from the straw pad. Drainage occurred mainly following a period of very heavy rainfall; this highlights the importance of applying sufficient bedding early in the season to allow capacity to absorb effluent following short period of heavy rainfall. In 2013/14 for the period when the cattle were on the pads (23rd September 2013 to late-January 2014), the estimated drainage volume was <1 mm and <1 kg/ha N was lost via leaching from the straw pad.

Straw bedding recommendations are given for a range of beef cattle types based on the quantity of straw bedding required to absorb the liquid input (excreta and rainfall) to the pad. These recommendations should be used in combination with a visual inspection of the pad and additional straw should be added where required to keep the surface of the pad clean and dry and to ensure there is no ‘pooling’ of liquid on the pad surface or any seepage of contaminated runoff from the pad.