Relationship between Rectal Findings of Corpus Luteum and Whole Milk Progesterone Levels in Postpartum Dairy Cows

Abstract

The reliability of clinical ovarian findings was assessed as an indicator of luteal function in primiparous dairy cows. The postpartum period of 103 cows following their first parturition was studied by thrice weekly rectal palpation of ovaries and whole milk progesterone assay from 1 week after parturition to the first insemination. The relationship between milk progesterone levels and 1101 ovarian findings was compared during the follicular phases, short luteal phases and during the early, mid and late thirds of normal luteal phases. The compatibility between elevated progesterone and palpable corpus luteum was 71%, and between low progesterone and lack of corpus luteum 77%. In 10% of all rectal examinations the finding was unspecified; i.e. the clinician could not differentiate between luteal and follicular activity. During the acyclic period prior to the initiation of luteal function, the proportion of false corpus luteum findings was 11%. The corpora lutea of the short oestrous cycles were more difficult to palpate than those of normal cycles. During early dioestrus the corpus luteum was significantly more difficult to palpate than during the rest of dioestrus. The percentage of unspecified findings was highest during early dioestrus.

The paper discusses the reliability of rectal examination as a method of diagnosing cyclicity and of evaluating the responsiveness of a cow to prostaglandin treatment.

Sammenfatning

Pålitligheten av kliniska ovariala observationer som indikatorer på luteal funktion hos mjölkkor värderades. 103 kors postpartuma period efter deras första kalvning undersöktes 3 gånger i veckan, med rektal palpation av ovarierna samt progesteronprov ur helmjölk från 1 vecka efter kalvning till den första mseminationen.

Förhållandet mellan progesteronnivån i mjölk och 1101 ovarieobservationer jämfördes under de follikulära faserna, korta luteala faserna samt under den tidiga, mittersta och sena tredjedelen av normala luteala faser. I 71% av fallen kunde corpus luteum palperas då progesteron halten var förhöjd, och i 77% av fallen sammanföll låg progesteronhalt med avsaknad av corpus luteum. I 10% av de rektala undersökningarana var observationerna ospecifierade, med andra ord kunde klininkern inte skilja mellan luteal och follikulär aktivitet.

Under den acykliska perioden före början av den luteala funktionen var andelen felaktiga observationer av corpus luteum 11%. Corpora lutea i de korta oeströsa cyklerna var svårare att palpera än de i normala cykler. Under tidig dioestrus var corpus luteum signifikant svårare att palpera än vid de övriga faserna av dioestrus. Under tidig dioestrus var andelen ospecifierade observationer störst. I artikeln diskuteras pålitligheten av rektal examination som en metod för att diagnostisera cyklicitet och för att bedöma en kos mottaglighet för prostaglandinbehandling.