FDA Poisonous Plant Database
AUTHOR(S): MacDonald, J.
TITLE: Macrocarpa poisoning.
YEAR: 1956 CITATION: N Z Vet J, 4(), 30 [English]
FDA #: F10062
ABSTRACT: The following is in the form of a letter as I had not, until recently, any intention of recording the matter and have not kept notes; but I am doing so now because I believe that I may, almost accidentally, have found something of value to others. In this district in the past few years I have seen several outbreaks of disease occurring in cows in an advanced state of pregnancy that I have diagnosed on circumstantial evidence alone as poisoning by ingestion of foliage of Cupressus marcocarpa, a common shade tree on New Zealand farms. Unfortunately, the matter of autopsies has been neglected because all the outbreaks have occurred at a time of the year when both the veterinary surgeon and the farmer are extremely busy, and an autopsy takes time and renders the carcase indisposable except by burial. The following is a description from memory of three outbreaks of disease: In July, 1952, a mature Jersey cow was examined and showed the following symptoms: she had aborted a few hours beforehand and two weeks before full term, She was recumbent, comatose, her temperature subnormal, the foetal membranes were retained, dark in colour, and the maternal cotyledons were enlarged. The diagnosis was milk fever and the cow treated accordingly. Call her cow number one. During the following night two other cows (numbers two and three) in the same herd aborted about one month before their time and in the morning showed the following: number two had retained the foetal membranes, looked very ill, and swayed, apparently from weakness, as she walked. Her temperature was subnormal. Straining was persistent and severe. An attempt was made to remove the membrane manually but was unsuccessful as the cotyledons were grossly swollen and it was impossible to peel off the allantois. Number three was in every way similar except that she did not appear so desperately ill as number two. No definite diagnosis was made, and the two animals were treated for metritis hy the insertion of sulphonamides into the uterus and intramuscular injection of penicillin. The following day, numbers one and two were dead and number three was desperately ill, although still on her feet. Two further cows had aborted and showed the same symptoms as numbers two and three. At this stage the owner volunteered the information that he had felled a couple of macrocarpa trees in the paddock where the cows were grazing. Examination of the trees showed that a considerable amount of the foliage had been eaten. Having read an abstract on the use of anti histamines in metritis, I injected the three survivors each with 8 c.c. of promethazine hydrochloride ("Phenergan" M and B). The result was quite spectacular, within an hour or so the straining had eased, the animals commenced to graze and within 24 to 48 hours the membrane came away without interference. The treatment was continued daily for three days. The following day a further four cows aborted, making a total of nine, the four showing in more or less marked degree the same symptoms as the four predecessors. All were treated with promethazine and all recovered rapidly. In the winter of 1954, a farmer in this district felled some macrocarpa trees where they were accessible to his in calf cows, and five of them aborted. They did not show the marked weakness of gait evinced in the previous outbreak, but showed the following symptoms: gross enlargement of the cotyledons and persistent, almost frantic straining. They were all treated with promethazine, some with only a single dose. They all recovered rapidly and they all lost the foetal membranes without further interference. An interesting point in this outbreak was the short period of time between treatment and the cessation of persistent straining and the commencement of grazing, being about one hour. In July, 1955, 1 was called in to attend a cow with a prolapsed uterus. She had aborted about three weeks before she was due to calve. She looked ill, but could move freely; the cotyledons were enormously swollen, being about the size of a whole hand, and the membranes were adherent. An attempt was made to remove the membranes, but it was found quite impossible to peel the attachments from the maternal cotyledons; in the attempt several cotyledons were sloughed without, however, any marked haemorrhage. The unattached portions of the membranes were removed and the uterus replaced. I remarked that I suspected macrocarpa poisoning, and was informed that the cow had broken through a fence the previous day into an enclosure where a macrocarpa tree had been felled, and had spent several hours there. Promethazine was injected, and a further injection given the following day, although this did not appear necessary as the cow was perfectly happy and grazing normally. Recovery thereafter was uneventful. I now believe that where there is abortion in cows in the late stage of pregnancy, characterized by marked swelling of the cotyledons, macrocarpa poisoning should be suspected, and that, in cases of such poisoning, antihistamine therapy is specific for clearing up the secondary symptoms.
GRIN #: 12659
STANDARD COMMON NAME:
LATIN NAME: Cupressus macrocarpa
STANDARD PLANT NAME: Cupressus macrocarpa Hartw. ex Gordon