Laura Pieper

Randomized, blinded, controlled clinical trial shows no benefit of homeopathic mastitis treatment in dairy cows

Mastitis is one of the most common diseases in dairy production, and homeopathic remedies have been used increasingly in recent years to treat it. Clinical trials evaluating homeopathy have often been criticized for their inadequate scientific approach. The objective of this triple-blind, randomized controlled trial was to assess the efficacy of homeopathic treatment in bovine clinical mastitis. The study was conducted on a conventionally managed dairy farm between June 2013 and May 2014. Dairy cows with acute mastitis were randomly allocated to homeopathy (n = 70) or placebo (n = 92), for a total of 162 animals. The homeopathic treatment was selected based on clinical symptoms but most commonly consisted of a combination of nosodes with Streptococcinum, Staphylococcinum, Pyrogenium, and Escherichia coli at a potency of 200c. Treatment was administered to cows in the homeopathy group at least once per day for an average of 5 d. The cows in the placebo group were treated similarly, using a placebo preparation instead (lactose globules without active ingredients). If necessary, we also used allopathic drugs (e.g., antibiotics, udder creams, and anti-inflammatory drugs) in both groups. We recorded data relating to the clinical signs of mastitis, treatment, time to recovery, milk yield, somatic cell count at first milk recording after mastitis, and culling. We observed cows for up to 200 d after clinical recovery. Base-level data did not differ between the homeopathy and placebo groups. Mastitis lasted for an average of 6 d in both groups. We observed no significant differences in time to recovery, somatic cell count, risk of clinical cure within 14 d after disease occurrence, mastitis recurrence risk, or culling risk. The results indicated no additional effect of homeopathic treatment compared with placebo. The advantages or disadvantages of homeopathy should be carefully assessed for individual farms.

Heritability of metabolic response to the intravenous glucose tolerance test in German Holstein Friesian bulls

Selection for improved health and welfare in farm animals is of increasing interest worldwide. Peripartum energy balance is a key factor for pathogenesis of diseases in dairy cows. The intravenous glucose tolerance test (ivGTT) can be used to study the metabolic response to a glucose stimulus. The aim of this study was to estimate heritability of ivGTT traits in German Holstein bulls. A total of 541 Holstein bulls aged 7 to 17 mo from 2 breeding stations were subjected to the ivGTT. Serum glucose concentrations were measured at 0, 7, 14, 21, 28, 35, 42, 49, 56, and 63 min relative to glucose infusion. The maximum increase in blood glucose concentration, glucose area equivalent, and blood glucose half-life period were calculated. Heritabilities were estimated using a univariate animal model including station-year-season and age as fixed effects, and animal additive genetic and residual as random effects. The estimated heritabilities were 0.19 for fasting glucose concentration, 0.43 for glucose area equivalent, 0.40 for glucose half-life period, 0.14 for the peak glucose concentration, and 0.12 for the maximum increase of blood glucose concentration. Correlations between ivGTT traits and breeding values for milk yield and composition were not found. The results indicate that heritability for response to glucose is high, which warrants further investigation of this trait for genetic improvement of metabolic disorders. Research is necessary to determine the target levels of ivGTT traits and potential associations between ivGTT traits in breeding bulls and periparturient diseases in their offspring.

Validation of Digital Microscopy Compared With Light Microscopy for the Diagnosis of Canine Cutaneous Tumors

Integration of new technologies, such as digital microscopy, into a highly standardized laboratory routine requires the validation of its performance in terms of reliability, specificity, and sensitivity. However, a validation study of digital microscopy is currently lacking in veterinary pathology. The aim of the current study was to validate the usability of digital microscopy in terms of diagnostic accuracy, speed, and confidence for diagnosing and differentiating common canine cutaneous tumor types and to compare it to classical light microscopy. Therefore, 80 histologic sections including 17 different skin tumor types were examined twice as glass slides and twice as digital whole-slide images by 6 pathologists with different levels of experience at 4 time points. Comparison of both methods found digital microscopy to be noninferior for differentiating individual tumor types within the category epithelial and mesenchymal tumors, but diagnostic concordance was slightly lower for differentiating individual round cell tumor types by digital microscopy. In addition, digital microscopy was associated with significantly shorter diagnostic time, but diagnostic confidence was lower and technical quality was considered inferior for whole-slide images compared with glass slides. Of note, diagnostic performance for whole-slide images scanned at 200× magnification was noninferior in diagnostic performance for slides scanned at 400×. In conclusion, digital microscopy differs only minimally from light microscopy in few aspects of diagnostic performance and overall appears adequate for the diagnosis of individual canine cutaneous tumors with minor limitations for differentiating individual round cell tumor types and grading of mast cell tumors.

Influence of food deprivation on intravenous glucose tolerance test traits in Holstein Friesian heifers

Glucose is essential for numerous cellular functions due to its involvement in energy supply from early development to adulthood. In the lactating cow, glucose demands by the mammary gland significantly increase to support milk production when compared with other tissues. Thus, insufficient blood glucose levels might predispose dairy cows to metabolic disturbances. The intravenous glucose tolerance test (ivGTT) is a suitable tool to characterize glucose metabolism and insulin responses, but results must be reliable and repeatable. One factor influencing ivGTT is food deprivation period, which has been considered as an obligatory requirement before conduction of glucose tolerance studies in monogastric species, whereas it has been permissive in ruminants. The objective of this study was to determine the influence of 5 fasting periods (0, 12, 24, 36, and 48 h) on ivGTT traits and insulin responses in German Holstein heifers. A total of 140 tests were conducted in 28 females aged 12 to 19 mo. Blood samples were collected every 7 min within 1 h. Assessed glucose and insulin parameters included basal serum glucose and insulin concentration, maximum glucose and insulin concentration obtained between min 7 to 21, and concentrations at min 63 (last sampling) relative to glucose administration, glucose area equivalent (GA), glucose area under the curve (GAUC), insulin area equivalent (InsA), insulin area under the curve (InsAUC), and blood glucose half-life time (GHLT). Serum glucose and insulin concentration were measured according to the hexokinase colorimetric method and solid phase radio immunoassay, respectively. The generalized linear mixed model was used to test for significant differences in all glucose traits and insulin responses at different fasting periods. The model used season and weight as confounding variables. Glucose and insulin concentrations at 0, 7 to 21 (maximum concentration), and 63 min were affected by the duration of food deprivation. The GA, InsA, GAUC, InsAUC, and especially GHLT were also affected by fasting period. A positive linear relationship between GHLT and length of food deprivation was found. Significantly higher GA, GAUC, GHLT values, and glucose and insulin concentration at min 63 were obtained at increasing fasting periods. High intraclass correlation coefficient (0.48) was found for GHLT. The results demonstrate that GHLT might be used to reliably characterize an individuals glucose metabolism and the importance of standardizing food deprivation schedules when performing an ivGTT in nongestating Holstein heifers.

Association of postpartum hypocalcemia with early-lactation milk yield, reproductive performance, and culling in dairy cows

Periparturient hypocalcemia is frequently observed and considered as a gateway disease that is associated with various health issues. The objective of this study was to evaluate the association of hypocalcemia with early-lactation milk yield, reproductive performance, and culling across a large number of different managerial systems. A prospective cohort study was conducted based on a convenience sample of 125 dairy herds from 8 federal states of Germany between February 2015 and August 2016. A blood sample was drawn from 1,709 animals within 48 h after parturition and analyzed for serum calcium concentration. After discarding cows (n = 283) with missing data, a total of 1,426 cows were considered for final analyses. The median time from calving to sampling was 14.0 h (interquartile range = 5.0-24.9 h). For each herd, a record of the herd management software was requested 150 d after the last cow was sampled. Serum calcium concentration of each cow was associated with early-lactation milk yield (Dairy Herd Improvement Association equivalent test 1 to 3), reproductive performance [days in milk (DIM) at first artificial insemination (AI), pregnancy at first AI, time to pregnancy within 150 DIM], and culling (until 60 DIM) data. Generalized linear mixed models were used to analyze continuous or categorical data. Shared frailty models were used for time to event data. Five different thresholds were used to define hypocalcemia. Thresholds ranged from 1.8 to 2.2 mmol/L using 0.1-mmol/L increments. Clinical hypocalcemia was defined as serum calcium concentration <2.0 mmol/L in combination with clinical signs (e.g., recumbency). The effect of hypocalcemia on milk yield was conditional on parity. In primiparous cows a serum calcium concentration <2.0 mmol/L (6.4% of cows were below this threshold) had no effect on milk production, whereas there was a tendency for multiparous cows with a serum calcium concentration <2.1 mmol/L (63.2% of cows were below this threshold) to produce 0.80 kg/d more milk compared with multiparous cows at or above the threshold. Multiparous cows suffering from clinical hypocalcemia produced 2.19 kg/d less milk compared with normocalcemic cows in early lactation. Calcium status was not associated with days to first insemination. Cows with a serum calcium concentration <1.9 mmol/L (34.6% of cows below this threshold) had decreased odds (odds ratio = 0.56) of pregnancy at first AI. A serum calcium concentration <1.8 mmol/L (24.1% of cows below this threshold) had a significant effect on time to pregnancy. Compared with animals with a serum calcium concentration ≥1.8 mmol/L, the hazard of becoming pregnant within 150 DIM was reduced when cows had a serum calcium concentration <1.8 mmol/L (hazard ratio = 0.68). Cows with a serum calcium concentration <2.0 mmol/L (44.3% of cows were below this threshold) had a 1.69 times greater hazard of being culled within the first 60 DIM compared with normocalcemic animals. The present study shows that the association of hypocalcemia with milk yield was conditional on parity and serum calcium concentration measured once within 48 h after calving. Considering reproductive performance and culling in early lactation, a negative effect of postpartum hypocalcemia was demonstrated.

Evaluation of glucose dose on intravenous glucose tolerance test traits in Holstein-Friesian heifers

Glucose metabolism in dairy and beef cattle has received considerable attention because balanced blood glucose is essential for numerous processes, such as milk production and general health. The glucose tolerance test measures the ability of an organism to regulate blood glucose levels. Glucose half-life time (GHLT) has high heritability and could serve as a potential parameter to breed for metabolic resistance. However, studies focusing on identification of an adequate glucose dose have not yet been conducted in cattle. The objective of this study was to analyze the effect of 5 different glucose doses (0.5, 1, 1.5, 2, and 3 g/kg of body weight0.75) on intravenous glucose tolerance test (ivGTT) traits and insulin responses in nongestating heifers. A total of 150 tests were performed in 30 Holstein-Friesian heifers aged 13 to 15 mo. Blood samples were obtained every 7 min after glucose injection until min 63. Glucose traits and insulin parameters included blood serum glucose and insulin concentration at min 0 (basal concentration), min 7 to 21 (peak glucose and insulin concentration), and min 63 (last sampling) relative to glucose administration, glucose and insulin area under the curve (GAUC and IAUC), and GHLT estimated between min 14 and 42. Serum glucose and insulin concentrations were measured according to the hexokinase colorimetric method and radioimmunoassay, respectively. Generalized linear mixed model was used to test for significant differences in ivGTT traits, insulin responses, and glucose elimination rates (k) over time at different glucose doses. Maximum glucose and insulin concentrations at min 63 increased with higher glucose doses. Significantly lower GHLT were obtained at increasing glucose doses, whereas GAUC and IAUC were significantly higher at increasing doses. The k values were affected by glucose dose and by time interval. Glucose dose greatly affected most ivGTT traits, insulin responses, and glucose elimination rates. Therefore, researchers should standardize their methods to achieve repeatable results and use the same time points for GHLT calculation. Higher glucose doses (≥1.5 g/kg of body weight0.75) triggered glucose concentrations above the glucose renal threshold during the initial 42 min, whereas the lowest glucose concentration failed to induce a maximum insulin response. Further research is necessary to determine an adequate dose inducing maximum insulin responses with minimum renal glucose losses.