The effect of metritis on luteal function in dairy cows.

BACKGROUND: Disturbed uterine involution impairs ovarian function in the first weeks after calving. This study analyzed the long-term effect of metritis on luteal function of 47 lactating Holstein-Friesian cows during the first four postpartum estrous cycles. Cows with abnormal uterine enlargement and malodorous lochia were classified as having metritis (group M, n = 18), and all others were considered healthy (group H, n = 29). Luteal size was measured once between days 9 and 13 of the first (group H, n = 11; group M, n = 12), second (group H, n = 23; group M, n = 18) and fourth (group H, n = 11; group M, n = 7) postpartum luteal phases. Serum progesterone concentration was measured at the same time. Sixteen cows (group H, n = 9; group M, n = 7) underwent transvaginal luteal biopsy for gene expression analysis of steroidogenic regulatory proteins during the second and fourth cycles. Cows with persistence of the corpus luteum (CL) underwent determination of luteal size, luteal biopsy and serum progesterone measurement once between days 29 and 33, followed by prostaglandin treatment to induce luteolysis. The same procedures were repeated once between days 9 and 13 of the induced cycle. RESULTS: The cows in group M had smaller first-cycle CLs than the cows in group H (p = 0.04), but progesterone concentrations did not differ between groups. Luteal size, progesterone concentration and gene expression did not differ between the two groups during the second and fourth cycles. Compared with healthy cows (10%), there was a trend (p = 0.07) toward a higher prevalence of persistent CLs in cows with metritis (33%). Persistent CLs were limited to the first cycle. Persistent CLs and the induced cyclic CLs did not differ with regard to the variables investigated. CONCLUSIONS: An effect of metritis on luteal activity was apparent in the first postpartum estrous cycle. However, after the first postpartum cycle, no differences occurred in analyzed parameters between metritis and control cows. Therefore, a metritis is able to impair luteal activity transiently, but does not seem to have a long-term effect on luteal function.

Gene expressions in the persistent corpus luteum of postpartum dairy cows: distinct profiles from the corpora lutea of the estrous cycle and pregnancy.

Persistence of the corpus luteum (CL) in cattle usually occurs during the puerperium and is associated with interference of prostaglandin (PG) F(2α) release from the uterus. The objective of the present study was to determine for the first time the gene expressions in the persistent CL compared with the CL of pregnancy and cyclic CL. Three types of CL biopsy samples were collected from 32 lactating Holstein cows: (1) CL persisting for 29 to 33 days after the first ovulation postpartum (persistent CL, n=9), (2) CL between days 29 and 33 of early pregnancy (CL of pregnancy, n=8) and (3) CL between days 10 and 13 of the estrous cycle (cyclic CL, n=27). mRNA expression of 2',5'-oligoadenylate synthetase-1 was upregulated only in the CL of pregnancy, confirming exposure to interferon-τ (IFNT) produced by trophoblasts in pregnant cows. mRNA expressions of immune tolerance-related factors (PGES and forkhead/winged helix transcription factor 3) were upregulated in the CL of pregnancy but not in the persistent CL, suggesting that IFNT controls upregulation of these genes. mRNA expression relating to some of the major systems such as lymphangiogenesis, inflammation and apoptosis were similarly upregulated in the persistent CL and the CL of pregnancy but not in the cyclic CL. The results suggest that the persistent CL may survive for a long period without changes in local immune tolerance but develops several major systems required for CL maintenance similar to the CL of pregnancy.

Comparison of visual and computerized estrous detection and evaluation of influencing factors.

The aim of this study was to compare the automatic estrous detection system (AED) Heatime® with visual estrous detection (VED). The study was conducted on 139 Holstein Friesian cows in one dairy herd in Northern Germany. The cows were fitted with activity collars from d 21 postpartum until d 40 of gestation and a 30-min visual estrous observation was conducted three times a day. In addition, as a separate part of the VED, estrous detection by exclusive consideration of standing estrus (SE) was investigated. Ovulation detected by regular trans-rectal ultrasonography and serum progesterone analyses served as gold standard to calculate estrous detection rate (EDR) and reliability rate (RR) for each of the three estrous detection systems (AED, VED and SE). Change in body condition antepartum and postpartum, lameness, milk yield and milk fat- milk protein- ratio (FPR) on the expression and detection of estrus were investigated. Estrus was more precisely detected by the AED (EDR: 85.1%) than by VED (EDR: 52.2%) and SE (EDR: 22.3%) (P<0.05). The RR when using the three methods did not differ (P>0.05). Changes in body condition, lameness, milk yield or the FPR were not associated with the estrous detection rate by the AED. The estrous detection rate by VED in lame animals (EDR: 24.2%) was, however, less than in cows without any lameness (EDR: 52.7%; P<0.05). In conclusion, the AED Heatime® system can be effectively used for estrous detection and can be used to more precisely detect estrus than with VED.