Inside the dust jacket:
"Shocked at the onset of puberty and the catastrophe she believes it brought on her parents, Barbara has since been a most dutiful daughter. Bound in dominance over them, she tends her afflicted parents, managing the beasts and the land single-handed on the isolated marshlands of Campbell's Reach.
"It is her brother Damian who reveals the secrets that the family has shared for the past thirteen years. As the destructive forces within each of them move towards a climax, Barbara is impelled to make the ultimate sacrifice."
Mr & Mrs Glover have 2 children, Barbara and her younger brother, Damian.
The book opens with an adult Barbara preparing a syringe of antibiotic for her affected mother, whose affectation (sic) is now infected.
Mother, Father and Barbara are all waiting for Damian, on a holiday break from university, to arrive. Parents and daughter are all tense with anticipation - Damian is their only link with the normal world - he is out in the world but like his family he carries the burden of their secret.
(if you haven't read the book and intend to, you may choose not to read on, or you may, read on...)
So, what is the burden, what happened?
The Glover family is experiencing their first winter at Campbell's Reach. The reader is told that the Glover cows are not good enough for entry into the Dairy Farmers Cooperative as they are deemed inferior due to deficiency in butter fat and subject nasty cow afflictions. Seen through the eyes of Damian as a child, when Barbara starts to menstruate neither of them know what is happening. The siblings find out via a confrontation with their parents over the disposal of her nightdress in the fire of the kitchen stove.
Barbara gets angry when her parents try to explain; tearing at her clothes and runs into the forest with her parents in pursuit. Damian stays in the kitchen, gorging himself on toast and syrup.
Eventually the three return and everything has changed; Barbara is gentler but firmly in charge. Mr and Mrs Glover have found their bovine selves* - they are a cow version of Centaurs and Mrs Glover has particularly ugly udders. Mr Glover asks for gun cartridges, "They'd shoot a bloody man...in this condition"* but Barbara refuses and so we are taken through the next 13 years via a delightful (others have described it as 'grim' and 'bleak') layered story, which one can read purely for its surface story or delve into further if you seek deeper meaning.
(* from A Dutiful Daughter)
if you want to know more, the book can be tricky to find as it had its last printing in 1985 but I've found a number of copies online at good prices. I may have some copies at the exhibition to pass on at cost.