Astridge Farm Project Update - Final

Key results

In this case study project:

  • The Biocomplex supplement had no effect on milk yield or composition post peak lactation.

  • It was not possible to measure ammonia emissions, therefore further research is needed to determine if the Biocomplex additive has the effect of reducing ammonia emissions from ruminant manure/ slurry.

Further research is also needed to determine the biological basis by which the Biocomplex additive interacts within the rumen and its effect on nitrogen use efficiency.

Background

South Astridge Farm is a dairy farm located in South Pembrokeshire owned and run by William and Katy Fox. The enterprise consists of 350 milking British Friesian cows and operates an autumn block calving system. All milk is supplied to First Milk through its regenerative farming programme. As such, the Fox’s are keen to produce milk that is as environmentally friendly as possible. 

One area the farm was keen to explore is the reduction of ammonia emissions from their herd. As such, this case study project aimed to investigate the effect of feeding a seaweed extract known as Biocomplex to dairy cows as part of their standard lactation concentrate fed during milking in the parlour. The overall aim of the project was to determine if the Biocomplex supplement could improve herd productivity as well as lowering ammonia emissions from slurry.

What was done

The case study ran from 8 December 2023 through to 30 June 2024. The case study consisted of two periods, an indoor winter housing period which ran from 8 December to 1 March and a spring/ summer grazing period which ran from 1 April to 30 June. No data was collected in March due to this being a transition period, where cows were transitioned gradually from the winter indoor housing system to being out at pasture for 24 hours in accordance with the weather.

Results 

Milk Yields

Milk yield was measured on a 7-day average basis for the indoor housing period (weeks 1 – 13) and the outdoor spring/ summer period (weeks 18 – 29). There were no significant differences detected in the 7-day average milk yields of cows fed the control or Biocomplex diet for the indoor housing period or outdoor spring/summer grazing period (Fig.1)

Fig 1: Milk yields over the trial period

Milk Composition

The butterfat and protein composition of monthly milk samples were monitored and there were no differences detected in the butterfat content of milk samples when expressed on a percentage basis, for the control group or the group fed the Biocomplex additive during the indoor housing period or outdoor grazing period (Figure. 2). 

 

Fig 2: Milk butterfat and protein results over the trial period

Look see slurry study

A look see slurry analysis study was conducted to look for any differences between samples (Table 1). It is important to note that the results of this study should be viewed with caution and no conclusions drawn from this data due to limitations with sample methodology and lack of experimental control. Nevertheless, the results of the study demonstrated slurry samples to have different dry matter compositions, however the ratio of urine to faeces within the samples were unknown and therefore could have been a contributing factor for this. 

The pH of samples revealed the slurry samples collected from the control group to be slightly more acidic in comparison to the sample collected from the Biocomplex group. With regards to the nitrogen content of the slurry samples, the Biocomplex group appeared to have a lower total nitrogen content and ammonium nitrogen content in comparison to the control group. 

As such, this generated questions with regards to the effect of the Biocomplex additive within the rumen and the effect of the additive on rumen metabolism and nitrogen use efficiency. This emphasises the need for further research to determine the biological basis behind which the Biocomplex additive interacts within the rumen.

Conclusions

  • In summary, the results of this case study demonstrate the Biocomplex additive to not have any negative effect on milk yield or quality as reflected by butterfat and protein composition.

  • Although a look-see slurry analysis study was conducted as part of this case study, no conclusions could be drawn from this data due to limitations with sample methodology, lack of replication and experimental control.

  • More reliable ammonia emissions measurement could potentially reveal more positive results with regards to nitrogen use efficiency on farm with potential benefits for the environment. However, further research is required to fully determine this. More research is also needed with regard to understanding the biological basis behind which the Biocomplex additive interacts within the rumen with specific investigation made on nitrogen use efficiency and rumen fermentation.

Please contact timtechnegolcff@menterabusnes.co.uk if you would like to receive a copy of the full final report for this project.