A comparison of the cytobrush and uterine lavage techniques to evaluate endometrial cytology in clinically normal postpartum dairy cows

This study compares cytobrush and lavage techniques for the assessment of endometrial cytology (EC) in clinically normal postpartum dairy cows. The EC samples were collected from Holstein cows (n = 35) during visit 1 (V1) at 20 to 33 d in milk (DIM) and 2 wk later during visit 2 (V2) at 34 to 47 DIM by using both techniques. A minimum of 100 cells were counted to determine the percentage of cells that were neutrophils (%PMN). The mean %PMN was significantly different between the techniques at V1 (P = 0.001), but not at V2 (P = 0.474). Overall, the %PM N decreased with time postpartum (r2 = 0.36; P = 0.001), but not within V1 (P > 0.05) or V2 (P > 0.1). Uterine diameter was negatively correlated with fluid recovery by the lavage technique (r2 = 0.41; P = 0.002). The mean %PMN was not influenced by the volume of fluid recovered in successful attempts, but 17% (12/70) of attempts yielded no fluid. In conclusion, the cytobrush technique is a consistent and reliable method for obtaining endometrial samples for cystologic examination from postpartum dairy cows.     

Risk factors for repeat-breeder syndrome in New South Wales dairy cows

A retrospective case-control study involving 1041 cow lactations from 10 commercial dairy herds in Australia determined relationships between biographic, production, reproductive and disease factors and repeat-breeder syndrome (RBS) (conception to greater than two inseminations). The study population was stratified into primiparous- and multiparous-cow sub-groups and logistic regression was used. Effects of herd were examined by including this variable alternatively as a fixed and a random effect. In the primiparous-cow fixed-effect model, the risk of RBS was increased with post-calving metritis, stillbirth, and with increasing days taken to reach peak milk yield, and reduced following dystocia. An inverted U-shaped relationship with total milk-solids percentage at the time of first service was detected. In the multiparous-cow fixed-effect model, the risk of RBS was increased in cows with chronic metritis, cystic ovarian disease (COD), in cows of parity >5 and in cows that were sub-fertile in the previous lactation. Increasing days to first recorded heat (DFH) reduced risk of RBS and a non-linear relationship with average 120-day milk-protein percentage was found. When herd was fitted as a random effect, stillbirth and 120-day average milk-protein percentage were no longer significant in the primiparous and multiparous models, respectively. The study emphasises the need to control appropriately for the clustering effect of herd and supports the need to minimise periparturient disease and improve nutrient balance to achieve optimal fertility in dairy herds.     

Pathology of natural rotavirus infection in clinically normal calves

During a longitudinal study of the epidemiology of rotavirus infection in a calf rearing unit, excretion of virus in faeces was detected by enzyme-linked immunosorbent assay in 40 of 48 (83 per cent) unweaned calves aged between three days and five weeks. Fifty per cent of the infected calves had no clinical signs of disease. Enterocytes containing rotavirus antigen and intestinal lesions were found in all of 12 clinically normal calves selected for necropsy between days 1 and 4 of virus excretion. Stunting and fusion of villi, exfoliation, disarrangement and vacuolation of enterocytes and the presence of cuboidal enterocytes were observed in infected calves but not in rotavirus-free control calves. Lesions predominated in the upper small intestine, where rotavirus was most abundant, especially on the first two days of virus excretion. The numbers of enterocytes infected with rotavirus diminished before the lesions resolved.     

Incidence of infertility in dairy cows

The incidence of anoestrus, suboestrus, delayed ovulation, cystic ovaries, repeat breeder cows, endometritis and other forms of infertility was studied in 283 herds over a period of eight years (2,304 cases). The total incidence of infertility (0.111 cases per cow per year) varied significantly from year to year. The peak of the seasonal variation occurred in December-April and did not correspond with the seasonal variation in calving. Both the size of herd and the type of housing affected the incidence of infertility, but the differences were great in respect of the various diagnoses. The incidence of ketosis by herd correlated significantly with the incidence of infertility by herd.     

The relationship between production and infertility in dairy cows

Extract

Each year increasing numbers of livestock are transported by land, rail, sea and air, vet documented observation of the behaviour of stock during transit has seldom been recorded. The trans-shipment of weaner calves between the North and South Islands of New Zealand provided an opportunity to gather information on conditions of travel and general adaptation to a journey of 1600 kilometres by road and air.     

The possible role of bovine herpesvirus type‐4 infection in cow infertility

Experimental and field studies have proven that the bovine herpesvirus type‐4 (BHV‐4) infection leads to various reproductive system problems. In this study, the role of BHV‐4 infection in repeat breeding was investigated serologically. Eighty‐four samples were obtained from repeat‐breeding diagnosed cows in two organized dairy herds; an equal number of healthy cows were sampled from the same farms. The rest of the samples (105) were obtained from reproductively normal cows that were breeding in 18 small enterprises as a control group. The seropositivity proportion in repeat‐breeding diagnosed cows was found to be significantly higher (69% (58/84)) than other cows (44% (37/84)) on the same farms. The lowest antibody positivity value for BHV‐4 was detected as 24.7% (26/105) in the samples from family‐type small farms. The odds ratio (OR) value was calculated as 2.834 in repeat‐breeding diagnosed and healthy cows on the same farms, while 6.778 was determined in cows with and without reproductive problems on organized farms compared to small farms. As a result, the BHV‐4 infection can be considered one of the reasons for repeat breeding besides other reproductive disorders.     

The events of normal and abnormal postpartum reproductive endocrinology and uterine involution in dairy cows: a review

The results of numerous hormonal profile studies in the dairy cow are reviewed with respect to specific hormone changes in the early postpartum period, and factors contributing to the onset of cyclic reproductive activity. Variations from the normal pattern of postpartum hormonal activity or uterine involution are reviewed also. The normal involutionary changes of the bovine uterus are discussed.     

Isoamylases in clinically normal dogs

Isoenzymes of canine serum amylase were evaluated by electrophoresis on cellulose acetate membranes in a discontinuous buffer system. Two isoamylase groups were identified in the serum of clinically normal dogs. Most of the serum amylase activity was the more cathodal isoamylase. The anodal isoamylase was rarely observed in serum from normal dogs and, when present, accounted for little of the enzymatic activity. Amylase activities of various tissues were determined and isoenzymes were identified. The anodal isoenzyme was found in the pancreas and uterus. The cathodal isoamylase had its origin mainly from the intestinal tract. Activities of other tissues were not greater than was serum amylase activity. Effects of feeding upon total serum amylase activity and isoenzyme composition also were examined over a period of 5 minutes to 7 hours. Feeding did not markedly alter the serum amylase activity.     

Leukotriene B4 in cows with normal calving, and in cows with retained fetal membranes and/or uterine subinvolution.

Two experiments were performed to study the relationship between leukotriene B4 (LTB4) synthesis and placental separation and uterine involution in the cow. In experiment I, the concentration and synthesis of LTB4 by caruncular tissue was lower in cows with retained fetal membranes (RFM cows, n = 11) than in cows that expelled the fetal membranes normally (NFM cows, n = 19). The presence of bacterial cell wall, especially of alpha-hemolytic streptococci and coagulase positive staphylococci enhanced LTB4 synthesis by allantochorion only in NFM cows. In the RFM group, Escherichia coli lipopolysaccharide decreased allantochorionic LTB4 synthesis. With caruncle, only epidermal growth factor increased LTB4 production in NFM cows. In experiment II, the caruncular and endometrial secretion of LTB4 was lower in cows with subuterine involution (SUI cows, n = 5) or cows with SUI and RFM (SUI+RFM cows, n = 4) than in cows with normal uterine involution (NUI cows, n = 8). This decrease was especially noticeable in the previously gravid horn. In the three uterine involution groups, there were no differences in LTB4 synthesis by caruncular tissue taken from the previously gravid horn. However, progesterone and a bacterial suspension of E. coli reduced the synthesis of LTB4. Estradiol had no effect on LTB4 synthesis at the end of the postpartum period. These results suggest that LTB4 may play an important role in both placental separation and uterine involution in cattle and LTB4 synthesis may be modulated by endocrine and bacterial factors.