Learning about Agriculture: 1. The Dairy

In the past 50 years dairy farming has changed dramatically; with widespread cross-sector advancements it has become a high-output production in order to minimize costs.  Gone is the era of wooden stools and hand-milking, swept aside by mechanization leading to automatic milking systems.

If there’s one thing I know about my dad is that he’s good with numbers. When we were a running dairy farm he was alwaysscribbling down a list of numbers on whatever piece of paper he could get his hands on and it wasn’t until I started this blog post that I quite realized just how much mathematics is involved in something like agriculture.  I tried my hand at attempting to figure out income produced from milk and well…I’m not quite sure how my fictional farm ended up with over quarter of a million from less than 150 cows.

The dairy industry is subject to dramatic changes in income which excludes farmers of financial stability. From looking at the variations in the farmgate price per liter (ppl) the small variations seem inconsequential, but when you add up all those liters, thousands of pounds are gained and lost each year.

In 2014, the farmgate ppl for milk was 31.59 pence[i]which resulted in a strong annual income of £77,000 in Wales in the 2013/14 financial year. The following year, the ppl had dropped to 24.46.  This 5p drop per liter resulted in an annual income of £33,000 in 2015/16. The volatile pricing is below farm costs leading to a decrease in dairy farms in the UK with Wales losing 666 dairy farms in the 10 year period of 2007-17[ii].

Processors buy milk from the farmer (farmgate price) depending on the milk composition – how much protein and butterfat it contains.  Therefore, farmers need to ensure that their feed is cost effective – cheap to buy or produce, and beneficial in milk composition consequence.

Buying feed is the largest cost to UK dairy farmers and so they have to do more than ‘grow grass’. Farmers have to make use of the land they have which means knowing it inside and out –and this thoroughness allows them to decide what to grow which will have the most impact on their livestock. Grazed grass costs the farmer 6p/kg while bought feed costs 25p/kg which is a large deduction from farm profits and from scouring the net I came across a rather different method for acquiring feed. I had never heard of this system before, but the ‘cut and carry’ system (which is where grass is cut daily and given to cows in the shed) has some compelling statistics for it use[iii].  At first I thought ‘This is a ridiculous method – just let the cattle out to graze!” Then I remembered something that I asked my dad when I was younger.  Some farmers will scatter animals in field, while other will put quite a fewin, and I asked which was better? I believed that it was the field with the fewer animals in as they have more room to graze but my dad said the opposite.  A higher cattle density means that you are able to rotate them around fields/sections of fields more often, meaning that they get a fresh supply of grass at more regular intervals, while the others will have to do with old trampled grass. A ‘cut and carry’ system would completely eliminate trampling of grass and maybe improve soil quality – when soil is tramped on with the heavy cattle hooves, it becomes compact, decreasing the amount of air spaces in the soil. Therefore, when it rains, the water can’t sink into the soil, increasing the likelihood of flooding. ADHB found that the system increased grass growth rates by 25%. Pretty good right?

The diet of a diary cow reflects in the milk composition produced.  As you may know, cows are ruminants which means that they ferment their food and re-chew the cud.  The bacteria break down the cud to produce volatile fatty acids (VFA) which is their major form of energy source (similar to glucose in humans).  VFA consists of three types of acids – acetic, propionic, and butyric.  The cow’s diet dictates the percentages of each acid e.g. high fiber produces acetic acid in the rumen, which is used in lipid synthesis therefore increasing butterfat percentage. One the other hand, starchy foods (grains) digested produce propionic acid, which increases milk protein[iv].  Both of these percentages are taken into account when determining farmgate milk prices.

Levels of SCC are also considered when determining prices. SCC stands for somatic cell count and is an indicator of milk quality.  Mastitis is a bacterial infection of the udder and there are two forms (a) subclinical which is where there are no outward symptoms of disease and so is detected through increase SCC counts and (b) clinical which is where symptoms can be seen such as changes in the milk (formation of clots due to aggregated WBCs) or inflammation of the udder[v].  As vet bills are hefty, farmers implement prevention strategies to reduce the risk of contacting and transmitting responsible bacteria. 

As a pharmacy student I am keen to know what drugs are used to treat mastitis, including the route of administration. Intramammary antimicrobials are the first line treatment option with differences in treatment between dry and lactating cows (turns out, cows do not produce milk all the time leading me to wonder how they are differentiated between in the dairy…note to self, ask dad).  Lactating cows are given high concentrations of antimicrobials in quick-release formulations with short withdrawal periods in order to reduce milk discarding (if a cow has been given antibiotics the milk cannot be sold to ensue that it is not present in the milk)[vi].  Looking through intramammary antimicrobials on the NOAH app you can quickly see the differences in dry and lactating formulations, with antimicrobials intended for dry cows are present in the milk for longer as compared to formulations for lactating cows.  Before now, I had my heart set on doing my final year research project on anythingto do with the brain, but now, exploring formulations intended for animals may be an interesting topic for me.  In pharmacy we are constantly reminded that drugs are only as effective as the patients allow them to be. Patient characteristics whether it be poor inhaler technique or poor compliance (intended or not) reflects on treatment success and disease progression.  Farmers are busy and so formulation scientists must take into account both animal and ‘carer’ factors, for example, three times daily administration of antimicrobials for who knows how long, to a couple dozen cows does not reflect ease of use.  Their entire day would be consumed with teat care.

I have a blog post planned on food production, and so I’ll leave this as a rather abrupt ending. However, what I will say is that this first post has taught me quite a bit in a very short time frame.  It’s taught me how scientific agriculture has become in order to stay afloat and how so many different factors need to be considered when running a farm.  It has also led me to wanting to know more about how we can tackle the problem of low milk prices and whether chain supermarkets should be doing more to protect British farming.  Food for thought for upcoming blogs in the series!

Until next time.

[i] United Kingdom Milk prices – Calendar Year Farmgate Milk Prices. DEFRA.

[ii] Welsh Government. 2019. Number of Farms by Size, Year and Farm Type.

[iii] AHDB. 2019. Cut and Carry, a best-practice guide. Available at: https://ahdb.org.uk/knowledge-library/cut-and-carry-a-best-practice-guide

[iv] Quinns. 2017. Factors that can Influence Milk Butterfat Levels at Grass. Available at: http://www.quinns.ie/index.php/factors-that-can-influence-milk-butterfat-levels-at-grass/

[v] Erskine J. (date unknown) Mastitis in Cattle. MSD Veterinary Manual. Available at: https://www.msdvetmanual.com/reproductive-system/mastitis-in-large-animals/mastitis-in-cattle

[vi] Wang, W et al. 2015. Development of intramammary delivery systems containing lasalocid for the treatment of bovine mastitis: impact of solubility improvement on safety, efficacy, and milk distribution in dairy cattle. Drug design, development, and therapy vol 9, pp.631-642.