Chloramphenicol was administered by constant IV infusion to 7 healthy postpartum cows at rates predicted to approach a steady-state plasma concentration of 5 micrograms/ml. After 8 hours of constant IV infusion, uterine tissues were removed surgically and were assayed for chloramphenicol concentrations. Mean plasma-to-tissue ratios of chloramphenicol concentrations were 3.05, 3.63 (6 cows only), and 3.22 for caruncles, endometrium, and uterine wall, respectively. Plasma-to-tissue ratios of the 3 tissues were not significantly different (P greater than 0.10). Intrauterine (IU) injections of chloramphenicol (20 mg/kg of body weight) were administered to 3 healthy postpartum cows. The mean value of the fraction of the drugabsorbed from the uteri of these cows was 0.04. Mean concentrations of chloramphenicol were 43.8 micrograms/g in caruncles, 34.6 micrograms/g in endometrium, 2.8 micrograms/g in uterine wall, and 2.9 micrograms/ml in plasma 8 hours after IU injections. Chloramphenicol has now been banned for use in food-producing animals in the United States because of its potential for causing toxicosis in human beings. It is illegal to use chloramphenicol in food-producing animals in the United States and in some other countries as well. This includes use by the IU route of administration because chloramphenicol and most drugs are absorbed from the uterus into the bloodstream and are distributed to milk and tissues.

Objective: To determine alterations of serum biochemical variables in relation to changes of near- and far-field mean grayscale histogram (MGSH) and attenuation rates in liver ultrasonograms of periparturient cows. Animals: 67 Holstein cows. Procedures: Cows were allocated on the basis of body condition score into underconditioned (n = 21), moderately conditioned (23), and overconditioned (23) groups. Serum samples (obtained every 10 days from 30 days before to 30 days after calving) were analyzed for aspartate aminotransferase, alanine aminotransferase, and γ-glutamyltransferase activities and BUN, albumin, calcium, and inorganic phosphorus concentrations along with digital estimation of near- and far-field MGSH values of liver ultrasonograms and deep attenuation. Values were compared among groups and within each group, and their correlations were determined in the pre- and postpartum periods. Results: Serum biochemical variables did not differ significantly among groups. Aspartate aminotransferase and γ-glutamyltransferase activities increased in the postpartum period. Fluctuations of alanine aminotransferase activity were not significant; BUN decreased significantly in the peripartum period. Albumin concentration decreased prior to parturition and remained low, but significantly increased after parturition. Calcium concentration decreased on day 10 but subsequently increased. Phosphorus concentration decreased stepwise until day 10 after calving. Postpartum biochemical variables had weak correlations with near- and far-field MGSH values in overconditioned cows. The highest levels of sound attenuation were found in overconditioned cows on calving day. Conclusions and Clinical Relevance: Liver ultrasonographic features were poorly correlated with changes of serum biochemical variables. This suggests that liver ultrasonography is not a good technique for estimating functional liver abnormalities in periparturient cows.

Ten healthy first- and second-lactation Holstein cows were observed from 1 week before to 1 week after calving and at postpartum day 30 to determine polymorphonuclear neutrophil (PMN) functional variation and immunoglobulin binding profiles. Blood and mammary PMN were obtained 3 times weekly and within 24 hours of calving. Functional traits measured included phagocytosis of Stapbylococcus aureus and in vitro chemotaxis through micropore filters in a Boyden chamber. Additionally, PMN were evaluated for endogenous binding of IgG1, IgG2, IgA, and IgM before and after in vitro chemotaxis. Exogenous binding of the same isotypes was determined after incubation in pooled colostrum, purified immunoglobulin, and pooled sera. Phagocytosis results indicated a significant and transient increase in percentage of milk PMN with associated, rather than phagocytosed, bacteria for 1 week after calving. Blood PMN phagocytosis was not significantly different during this period. Though total chemotaxis was essentially unchanged, the percentage of PMN that were unable to complete migration increased substantially on the day of calving, an effect that disappeared by postpartum day 4. A significant (P < 0.01) positive correlation (r = 0.29) between percentage of PMN migrating completely through the micropore filter and percentage of blood PMN with associated bacteria was observed. Changes were not observed in endogenous immunoglobulin binding, with the exception of a peak in relative fluorescence intensity for IgG1 on the day of calving; this disappeared within 2 days after calving. Correlations between relative intensities of IgG2, and IgM, and percentage of mammary neutrophils phagocytosing were 0.37 and 0.70. Exogenous binding of antibody to blood neutrophils before chemotaxis was generally accomplished most effectively by pooled colostrum, whereas use of pooled sera markedly reduced binding and percentage and intensity of IgM in all cases. Binding of all isotypes was slightly higher before than after calving. Incubation of blood neutrophils in isotypes G1, G2, A, and M after chemotaxis yielded lower immunoglobulin binding among all isotypes, particularly IgM. Fluctuations in neutrophil function were observed immediately around parturition, and these changes correlated strongly with endogenous immunoglobulin-binding profiles.

Neutrophils from 8 Holstein heifers were evaluated for function during the periparturient period. Random migration, ingestion of bacteria, superoxide anion production, native (nonenhanced) chemiluminescence, iodination, and antibody-dependent, cell-mediated cytotoxicity by neutrophils were determined. Foremilk samples were evaluated for bacteria. Significant (P less than 0.05) increases in random migration of neutrophils, iodination, and chemiluminescence were evident 2 weeks before parturition and then decreased dramatically by the first week after parturition. These impairments of neutrophil function after parturition may be manifested as a severe cumulative deficit in the native defenses afforded by the neutrophil.

During the 1986 lambing season, 33 Michigan sheep producers submitted all lambs that had died before weaning to the Michigan State University Diagnostic Laboratory for necropsy. Inductively coupled argon plasma emission spectroscopy was used to measure 22 elements in the liver of 888 of the lambs submitted. Mean concentrations of each element were established and compared with literature values of established deficient, normal, and toxic concentrations. Mean values in milligrams per kilogram of wet weight were as follows: A1, 3.843; As, less than 1; Ba, 0.176; Ca, 128.2; Cr, 0.778; Cu, 56.82; Fe, 491.6; Hg, less than 2; K, 2,150; Mg, 138.4; Mn, 2.776; Mo, 0.489; Na, 1,384; P, 2,583; Pb, 1,453; Sb, less than 1; Tl, less than 5; Zn, 68.31. In only 11 lambs did the liver contain As, B, Cd, Co, Hg, Sb, Se, or Tl in detectable concentrations.

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.

The effect of metoclopramide (MC), a dopamine antagonist on luteinizing hormone (LH), was examined in anestrous primaparous cows. Metoclopramide has been found to be beneficial in overcoming fescue toxicosis; increasing LH secretion stimulates return to ovulatory function after parturition. Consequently, if MC had negative effect on LH secretion, it would indicate that administration of MC to reproducing animals might be limited. Of 14 postpartum (47 to 66 days) cows, 7 were given MC (4 mg/kg of body weight, IV), and 7 served as controls. Blood was obtained via jugular cannulas at 15-minute intervals for 8 hours; MC was given at the end of the first hour, and gonadotropin-releasing hormone (GnRH, 7 mg/kg), was given IV at the end of hour 7 as a challenge stimulus for LH secretion. Prior to GnRH administration, MC did not have significant effect on LH secretion, as judged by mean serum LH concentration, LH pulse frequency, and LH pulse amplitude. Administration of MC resulted in greater (P < 0.05) LH response to GnRH, indicating enhanced secretory ability when the pituitary gland was challenged. Serum prolactin concentration was increased (P < 0.01) by MC administration. Therefore, MC did not have adverse effect on LH secretion in postpartum cows.

A total number of 12 postpartum (pp) Nubian goats were included in the study to measure the uterine involution by ultrasonography from day 3 to 31 pp. Coinciding with ultrasonography, blood samples were collected at every 3 days to monitor the ovarian activity by measuring plasma progesterone (P4) concentration using progesterone radio-immuno-assay (RIA). Uterine diameter (UD) and uterine lumen (UL) were maximum on day 3, and minimum on day 31 pp. More than 50% of uterine involution occurred between day 3 and day 14 pp. The end of uterine involution was characterized by small UD and absence of lochia in the UL. The maximum (0.87±0.4 ng/mL) and minimum (0.54±0.2 ng/mL) plasma P4 levels were reported on day 27 and day 7 pp, respectively. Completion of uterine involution was recorded at 22±3.3 days pp. There was a negative correlation between P4 level and uterine parameters (UD and UL). It can be concluded that ultrasonography is a reliable tool to determine uterine involution in Nubian goats.