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    Cow health and The Environment

    The UK Government aims to achieve ‘net zero’ for greenhouse gases (GHG) in the UK by 2050. This target affects everyone and all businesses in the UK, including agriculture, which is responsible for just under 10% of the UK’s emissions. GHG relevant to agriculture are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O).

    • Carbon dioxide is produced when fossil fuels (petrol, diesel, etc) are used.
    • Methane is produced (belched) by cattle and sheep during food digestion in the rumen – as well as its GHG effect, it represents a waste of 5-10% of the energy contained in the diet.
    • Nitrous oxide emissions arise from nitrogen in the soil (derived from fertiliser and organic matter – slurry/manure – applied to fields). Runoff and leaching of nitrogen into water courses also has an environmental effect.

    How does cow health affect these outputs?

    Basically, this revolves around efficiency. We want cows to be producing milk as efficiently as possible, because however much or little milk they produce, they are still eating (and belching methane into the air) and still producing urine and muck (and so excreting nitrogen into the environment). Therefore, higher-yielding cows have lower GHG emissions per litre of milk because their inevitable maintenance functions and outputs can be divided or allocated between more litres of milk. For a cow giving 10 litres, 54% of feed energy is used for maintenance; whereas a cow giving 30 litres only uses 18% for maintenance (van Soosten, 2020). Similarly, increased age of heifers at first calving or longer dry periods (due to cows taking too long to get back in calf) lead to increased GHG emissions per litre of milk, when looked at over the cow’s lifetime. This is due to more ‘unproductive’ days (no milk produced).

    Livestock farming emissions can be reduced by a variety of methods, including improved animal nutrition (including the use of specific feed additives), improved slurry/manure management, improved crop farming and use of anaerobic digesters. However, improving ruminant health is also recognised as an important way to reduce GHG emissions; production disease can increase the carbon footprint of dairy cows by 10% (Centre for Innovation Excellence in Livestock, 2020).

    How do poor health and fertility increase GHG emission?

    Firstly, as above, animals suffering from disease/poor health are less productive (lower daily weight gains or milk yield). This is due to reduced feed intakes, and also increased energy expenditure associated with infection/ inflammation.

    Secondly, improvements in fertility (largely due to the requirement to keep fewer ‘unproductive’ replacements) can lead to a 24% reduction in farm methane emissions (Garnsworthy, 2004).

    Thirdly, poor health and fertility is associated with increased culling rates. Modelling showed that cows culled after 5 lactations had a lifetime carbon footprint per litre of milk 40% lower than cows culled after their first lactation (van Soosten, 2020).

    So, healthier cows have a beneficial effect on the environment, relating to efficiency of resource use. Of course, the efficiency also has a beneficial effect on farm profitability. It has been shown many times that poor health and fertility are costly to dairy farmers. At the recent Society of Feed Technologists conference, Jean Margerison from Nottingham University talked about the costs of rearing heifers. When compared with recommended first calving age of 22-24 months, calving heifers at the national average of 29 months cost an extra £400-500 in feed costs alone. That doesn’t take into account the higher lifetime yield and return on investment for the earlier calving window; in total, the extra costs of calving at 29 months can approach £3000.

    So, healthy cows are better for both the environment and the farm balance sheet. Approximately 75% of dairy cow disease occurs within the first month of calving, and the transition period also affects subsequent fertility. Subclinical ketosis (excessive negative energy balance) post-calving is associated with an increased carbon footprint, due to prolonged calving interval (31% of effect), discarded milk (30%), reduced milk production (19%) and culling of cows (20%) (Mostert, 2018). This highlights the importance of the transition period.

    Glycal Forte® supports your cows in three ways: improved rumen health and function, bio-available calcium to support her needs post-calving and glycerol for energy. For a healthy transition and beyond, get in touch today.