A serious query: were cows in nineteenth century Britain as rectangular shaped as painters envisioned them?

The first painting is of the Craven Heifer who is, according to the BBC, "the fattest ever cow". There is also a sculpture of her in which her body is also rectangular. Is this based on the portrait or is this what cows become when they gain weight? https://www.bbc.com/news/uk-england-york-north-yorkshire-43715407

Further research (PhD in the making) appears to show that the fatter a cow is, the more rectangular it becomes. Also, cows from Jersey seem more moulded like those nineteenth century moouses ( @TheShentonStone can you confirm?) The plot thickens.

Were all C19 British cows really fat, and thus, rectangular? Did industrial cow breeding phase out the rectangular frame? Did artists only draw fat rectangular cows to represent familial wealth/status? Were Jersey cows setting the cow beauty standards then? THE QUESTIONS.

Any cow art historians, please direct me to the answer for this rectangular dilemma. This has been your nightly break from the contemporary soul destroying news cycle. Mooving on.

The plot continues. After hearing that @simonelalala had seen the cows I wondered if it also applied to other livestock. Google images confirmed that YES, SHEEP WERE ALSO RECTANGLES IN C19.

PLUS the sheep led me to @AEwbank 's article: "In 19th-Century Britain, The Hottest Status Symbol Was a Painting of Your Cow." She coined the livestock as "surprisingly geometric", which is how I will forever describe my body type: https://www.atlasobscura.com/articles/britain-cows-pig-sheep-paintings-livestock

What does @AEwbank say? That the fat rectangular livestock were "prized as proof of their owners’ success in breeding for size and weight", thus setting the beauty standard for livestock paintings nationwide. AKA, fat and rectangular sheep were the C19's Birkin.

AND there is actual academic work on this art (academia my love!!) In 1976 the late Juliet Clutton-Brock wrote that this shape of livestock became "extinct or changed out of all recognition". So perhaps mass industry can take the rectangle out of the cow. https://www.jstor.org/stable/40273684 

On a side note, I am officially locked out of @UniofExeter 's JSTOR access. Yes, I graduated over a year ago, but it still stings. All the information on C19 British rectangular livestock, locked away, much like the livestock were themselves I'm sure. Seems fitting.

The questions still loom: were fat rectangular animals the norm in C19 Britain and artists painting reality? Or was fat rectangularness projected by art based on a few thiccies and the animals conformed thereafter? Chicken or the egg (were chickens squares?)