Modern-day space race (April 22)

Providing housed dairy cows with more space to exhibit natural behaviour offers both milk production and cow comfort benefits. A recent study has put some solid science – and figures – behind what producers have long suspected.


TEXT KATE SMITH


Current cow-housing recommendations on loafing areas and total space per cow lack clarity and vary widely. That’s why, as part of his PhD studies, vet Jake Thompson, from LLM in Derbyshire and researcher at the University of Nottingham, decided to evaluate the impact of indoor living space on dairy cow production, reproduction and behaviour.



“Because 99% of UK dairy cows will be housed at some point during the year, it is important to consider improving management when cows are inside. Cows in some units have double the amount of space that others do but we lacked the evidence to quantify how extra space impacted them,” he explains.


‘Living space’, the additional non-lying space availability for dairy cows above that deemed to be a baseline requirement, can be calculated easily using simple building measurements. This will help reduce the ambiguity and uncertainty which currently accompanies discussions about ‘loafing areas’.


“Producers are asked to provide ‘loafing areas’ without appropriate guidance of what and how this will impact their cows. For example, opinions differ on whether passageways should be considered as loafing areas,” says Dr Thompson.


Trial work measured the total space provided on 50 dairy units across Great Britain and found it ranged from 5.4 to 12.7m2 per cow, with the average providing 8.3m2 . These results formed the foundations of an AHDB-funded trial at the University of Nottingham to evaluate the impact of indoor living space on 150 cows from its high-yielding housed herd.


A year-long randomised controlled trial was carried out in a purpose-built facility. This allowed precise measurement and novel configurations of the housed area. Holstein dairy cows were randomly allocated into a ‘high’ or a ‘commercial average’ living space group. The high-space group were given 6.5m2 living space within 14m2 per cow overall space, compared to the control group with 3m2 living space within 9m2 per cow total space.


All other aspects of their environment, management and husbandry were identical between groups, to ensure direct comparison between the two groups. And, also with that in mind, cows were partnered by parity and days in milk, which meant that group structure was also the same throughout the trial.


“We wanted to measure the effect of living space against three main parameters: production, behaviour, and reproduction/fertility,” says Dr Thompson.


Production was primarily measured using daily yield per cow. Rumination time, bodyweight, and milk solids data were also compared between groups. To monitor behaviour, cows were fitted with their own wireless geo-location sensors, basically a ‘Fitbit’ for cows, which sent a location measurement every seven seconds.


Designated areas


Comparisons were made between groups on the time spent in key designated areas such as living space, feed-face and cubicles, as well as environmental enrichment use. Time taken to pregnancy was used to measure the reproductive performance of the cows between the two groups. All key reproductive data such as AI and PD records were collected. Underlying reproductive physiology was analysed using samples of anti-müllerian hormone (AMH) and milk progesterone levels.


“We found that cows in the high-living-space group gave similar peak yields to those in the control group, but held their yield higher for longer throughout lactation,” says Dr Thompson. “This led to an increase in milk yield from 14,644 litres to 14,746 litres, equivalent to more than 100 litres per cow per 305-day lactation.


“The largest yield effect was observed in heifers. Those in the high-space group produced, on average, more than 600 litres additional milk per lactation compared to their control-space counterparts, with yields increasing from 11,592 litres to 12,235 litres.


But providing more space did not have such a positive impact on reproduction, with cows in the high-space group taking longer to conceive. That said, all other fertility parameters measured showed no difference between groups.


“When these results were assessed in a simulation model, it indicated that the reduced reproductive performance was compensated for by the increased milk volume in the higher-space group. So it is still likely to be economically beneficial to provide more living space for housed cows,” says Dr Thompson.


Increased space also provided enhanced cow welfare through significant behaviour changes. “Cows in the higher-space group spent an extra 65 minutes per day lying down and an extra 10 minutes each day at the feed face. And they spent less time in the additional living space and more time in the cubicles,” he adds.


This is the first long-term study to show that providing increased living space leads to meaningful benefits to milk production and the behaviour of housed dairy cows. “Given the current large variation in space allowances in dairy accommodation across Great Britain, the results of this trial should help producers decide on how best to invest in improving housing and, ultimately, improve cow comfort, wellbeing and productivity.”



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