Detection of a corpus luteum in apparently anoestrous cows by manual palpation, transrectal ultrasonography and plasma progesterone concentration

AIMS: To determine the level of agreement between transrectal ultrasonography, manual palpation and measurement of progesterone in the detection of corpora lutea in post-partum cows. To evaluate the reproductive performance of cows not detected in oestrus prior to mating, but detected with a corpus luteum at the start of mating. METHODS: Cows from seven herds which were not detected in oestrus were examined between 5 and 7 days before the herd's planned start of mating. Ovaries were examined by palpation and ultrasonography in 160 cows and plasma progesterone concentrations were also measured in 103 cows. Insemination dates and pregnancy data were recorded in 159 cows not detected in oestrus but having a corpus luteum and 1405 cycling herd mates. RESULTS: The level of agreement between ultrasonography and measurement of progesterone (kappa = 0.74) was higher than with manual palpation (kappa = 0.67) although it was significant for both techniques (p <0.001). Cows which were not detected in oestrus, but detected with a corpus luteum had a longer interval to first service (12 v. 10 days, p <0.05) and conception (19 v. 15 days, p = 0.01) than cycling herd mates and had a higher empty rate (9.7% v. 3.8%, p <0.001). CONCLUSIONS: These data indicate that ultrasonography may provide a better diagnostic tool for examining cows not detected in oestrus than manual palpation or measurement of progesterone concentration. Cows not detected in oestrus but having a corpus luteum were shown to have significantly poorer reproductive performance than cycling herd mates.     

Outcome and racing performance after internal fixation of third and central tarsal bone slab fractures in horses. A review of 20 cases

Twenty horses with central and third tarsal bone slab fractures, were treated internal fixation. Eighteen of the 20 cases were Standardbred trotters, one was a Thoroughbred racehorse and one a Swedish Warmblood. The central tarsal bone (CT) was involved in 12 cases and the third tarsal bone (T3) in 8 cases. The fractures were treated by lag screw fixation with one (18 cases) or two (2 cases) 3.5 or 4.5 mm cortical screws. Horses were confined to stall rest for one month and then put on a gradually increasing exercise programme. Convalescence time was 3-8 months until the fracture had healed and training could be resumed. Fifteen of the horses regained athletic soundness. Thirteen of the horses (72%) raced after surgery (12 Standardbreds and 1 Thoroughbred). Nine (69%) of these 13 horses won races after surgery.     

Immunocytochemical demonstration of lymphocyte subsets and MHC class II antigen expression in synovial membranes from dogs with rheumatoid arthritis and degenerative joint disease

The study describes the distribution of canine leucocyte antigens in synovial membrane biopsies from six dogs with canine rheumatoid arthritis (CRA) and from eight dogs with osteoarthritis (OA) secondary to spontaneous rupture of the cranial cruciate ligament (CCL) (n = 5) or patellar luxation (n = 3). Synovial membranes from five dogs without evidence of joint lesions were used as control tissues. In the subsynovium of dogs with normal joints CD5+, CD4+, CD8+ and alpha beta TCR+ lymphocytes were present only in low numbers. With monoclonal antibody (mAb) to MHC class II antigen, either none or up to 20-30% of synovial lining cells were immunoreactive. Furthermore, scattered MHCII+ stromal cells were seen in the deeper subsynovial layer. In synovial membrane biopsies from dogs with CRA numerous diffusely and perivascularly distributed CD5+ lymphocytes were found in the subsynovium. CD4+ cells outnumbered CD8+ cells and were more numerous in the perivascular areas. In all the CRA cases examined, there were markedly higher numbers of alpha beta TCR+ cells compared with gamma delta TCR+ cells. With mAb to CD21, low numbers of immunoreactive lymphocytes were demonstrated. In all the CRA cases, a marked increase of MHC class II antigen expression was noted. In the majority of samples, 50% or more than 90% of the synovial lining cells were strongly MHC class II+. Throughout the subsynovial layer there were numerous MHC class II+ cells and included those with dendritic morphology and inflammatory mononuclear cells. Furthermore, marked perivascular immunoreactivity for MHC class II antigen was found. In biopsies from dogs with OA, there were markedly lower numbers of subsynovial CD5+, CD4+ and CD8+ lymphocytes. T-cells were mainly diffusely distributed. In three of the eight OA dogs examined, there was an increased percentage of synovial lining cells expressing MHC class II. The majority of OA cases had subsynovial major histocompatibility complex (MHC) class II+ cells with a dendritic morphology.     

The immune response and PBMC subsets in canine visceral leishmaniasis before, and after, chemotherapy

Peripheral blood mononuclear cell subsets, in vitro lymphoproliferative response to leishmanial antigen, and Leishmania-specific serum antibody levels were examined in 11 dogs, naturally infected with L. infantum, and 9 healthy control dogs. A decrease in the percentage of CD4+ T-cells and an increase in the proportion of gammadelta T-cells and sIgG+ B-cells were observed during canine visceral leishmaniasis (CVL). These changes may be responsible for the marked humoral response and the absence of in vitro lymphoproliferation to mitogen and specific parasite antigens. This possibility was supported by the analysis of these subsets after treatment with amphotericin B. One month after therapy, a significant increase in the percentage of CD4+ T-cells and a decrease of gammadelta T-cells and sIgG+ B-cells were observed. At the same time, the lymphocyte blastogenesis assay with leishmanial antigen was positive and the levels of specific antibodies to Leishmania were significantly lower than before the treatment. Five months after therapy, lymphocyte proliferative response to LSA disappeared, antibody and lymphocyte subsets levels returned to those observed during CVL. Therapeutic failure in CVL is associated with the inability of antileishmanial drugs to completely revert the profound immunodepression induced by the infection and prevent relapse.     

The detection of CD2+, CD4+, CD8+, and WC1+ T lymphocytes, B cells and macrophages in fixed and paraffin embedded bovine tissue using a range of antigen recovery and signal amplification techniques

In order to develop procedures to label the main bovine leucocyte populations in paraffin embedded sections, the immunoreactivity of 25 monoclonal antibodies (mAbs) to different leucocyte antigens was assessed with formal dichromate (FD5) and 10% formalin fixation, a battery of antigen retrieval (AR) methods, and the biotin-tyramide amplification system. All the leucocyte populations investigated (CD2+, CD4+, CD8+, WC1+ T lymphocytes, B cells and macrophages) were strongly and specifically detectable under an appropriate combination of mAb, AR method and signal amplification system. CD4 and CD8 required the most stringent conditions and could only be demonstrated in FD5 fixed sections. For detection of CD2, WC1+ T lymphocytes, B cells and macrophages, all the mAbs produced immunoreactivity in FD5 or formalin fixed tissues. The need to check a range of different AR methods is stressed, as the method of choice varied for each individual mAb. The incorporation of the signal amplification system was necessary to observe a strong signal and the complete distribution of CD4, CD8 and B cells. Fixation by FD5 proved to be better than formalin for the preservation of surface antigens but it was inferior for the detection of markers which were found to show cytoplasmic immunoreactivity, such as the macrophage marker MAC387 or the B cell markers BAQ155 or IL-A59.     

Dynamics in the membrane organization of the mammalian sperm cell and functionality in fertilization

The capacitation process of sperm cells involves complex changes in the composition and orientation of molecules at the surface of the sperm cell. Here we focus on the lipid architecture in the sperm plasma membrane and demonstrate that the sperm plasma membrane is not static but is an extremely dynamic structure. Advanced fluoroscopic techniques enabled continuous monitoring of lipid organization in living cells and extremely rapid lipid movements were observed. The orientation of lipids in the sperm plasma membrane changed under capacitative treatments, was found to be sensitive for temperature and also changed upon binding of sperm cells to the zona pellucida. The changes in membrane properties coincided with an activation of protein kinases resulting in tyrosine phosphorylation of specific plasma membrane proteins. The detected membrane changes relate to intrinsic membrane properties such as fluidity, permeability, adhesiveness and fusibility. We think that these results may provide a physiological basis for new assays, able to discriminate between functional and non-physiological sperm cells.     

Repeatability in ranking of dairy farms on technical and economic performance over years

Repeatability of farm average 305-day milk production and gross margin per 100 kg of milk was evaluated for 39 farms. Ranking of gross margin, its underlying factors (i.e. milk price, returns from cull cows and calves, costs of concentrates, and costs of roughage purchases per 100 kg of milk), and 305-day milk production was not completely random over the four years of the study. The coefficient of concordance ranged between 0.55 and 0.82. The costs of roughage purchased had the lowest concordance over time, and 305-day milk production had the highest concordance. For each year and each farm, the difference between average gross margin and farm-specific gross margin was calculated. The standard deviations (SD) of these values was calculated for each farm, and showed differences between farms in variability in gross margin over years (the farm-year-specific SD varied between farms from 0.56 to 5.73). All the underlying factors showed a deviation over years. So, variability of gross margin can be due to changes in all underlying factors. The impact on gross margin of purchased roughage was not of major importance because its absolute impact on the gross margin is small. We concluded that milk-production data over one year is a reliable indicator for the typical farm milk production. Because gross margin fluctuates considerably over time, however it is preferred to base economic research on data from more than one year.     

Relationships between bulk-tank antibodies to Ostertagia ostertagi and herd-management practices and measures of milk production in Nova Scotia dairy herds

Monthly bulk-tank milk samples were obtained from 415 Nova Scotia dairy herds in each of the months of July-September 1998 and tested using an indirect microtitre ELISA against a crude saline-extract, whole-worm Ostertagia ostertagi antigen. ELISA results (optical densities (ODs)) were consistent across months (r=0.85) but there was considerable variation among herds. A questionnaire was sent by mail to all producers; information on management factors that would potentially influence parasite burdens in the herds was obtained from 239 farms. Data on annual milk production, summer milk production (July-September) and seasonal decline in milk production were obtained from the Animal Productivity and Health Information Network (APHIN) database. Associations between management practices and ODs, and between ODs and milk-production parameters were studied. Some management practices known to be associated with parasite burdens had expected directions of association with the ODs, giving supporting evidence that the ELISA is a reasonable measure of parasite burden. Most notably, ODs were increased with greater exposure of heifers or milking cows to pasture. ODs were not associated with either annual milk production or seasonal decline in milk production. However, there was a substantial relationship between the herd OD value and the level of milk production during the summer. An increase in the OD from 0.58 to 0.83 (the interquartile range of ODs) was associated with a reduction in production of 1.25kg/cow/day.