Erratum to “Blood calcium as a prognostic indicator of success after surgical correction of left displaced abomasum” (JDS Commun. 2:207–211)

JDS Communications · 2022-03-01

[This corrects the article DOI: 10.3168/jdsc.2021-0079.].

Impact of Satisfactory/Unsatisfactory Grading on Student Motivation to Learn, Academic Performance, and Well-Being

Journal of Veterinary Medical Education · 2022-12-02 · 6 citations

Satisfactory/unsatisfactory (S/U) grading is often proposed to ameliorate stress by reducing the competitive nature of letter grading. Though explored considerably in human medical programs, minimal literature focuses on the veterinary school setting. The purpose of this study was to evaluate the impact of S/U grading on veterinary students' motivation to learn, academic performance, and well-being. Cornell University's COVID-19 pandemic response provided a unique opportunity to compare S/U and letter grading on the same population of students during a single pre-clinical foundation course, with the first half being graded S/U (spring semester 2020), returning to letter grades in the second half (fall semester 2020). Students were retroactively surveyed on the effect of S/U versus letter grading on their overall educational experience and well-being, with 67.8% class participation. The majority of respondents (71.3%) stated that S/U grading had a positive impact on their overall learning experience. More than half (53.8%) perceived that they learned the same amount of information and had the same level of motivation (58.8%), even though most (61.3%) stated that they spent less time preparing for S/U assessments than letter grade assessments. Positive impact factor effects for S/U grading included decreased stress, more time for self-care, improved learning, and increased learning enjoyment. S/U grading did not negatively impact academic performance. In conclusion, this study demonstrates that, in our particular study population and setting, S/U grading conferred well-being and learning experience advantages to students without any reduction in motivation for learning or academic performance.

Diurnal variation of milk fatty acids in early-lactation Holstein cows with and without hyperketonemia

animal · 2022-06-01 · 7 citations

Estimates of milk constituents by Fourier-transform mid-infrared (FTIR) analysis have been shown to be a useful tool in monitoring energy deficit in early-lactation dairy cows. Our objectives were to describe the diurnal variation in milk fatty acids (FAs) and estimate the association of hyperketonemia with concentrations and diurnal patterns of FTIR estimates of milk FA. Blood samples were collected via jugular catheters bihourly for 5 d from multiparous Holstein cows (n = 28) enrolled between 3 and 9 days in milk. Milk samples were collected thrice daily at 0600, 1400, and 2200 h for d 2, 3, and 4 of the study period. Cows were retrospectively classified as hyperketonemic (HYK; n = 13) or non-HYK (n = 15) based on blood beta-hydroxybutyrate (bBHB) concentrations analyzed during the study period. Cows were classified as HYK if bBHB was ≥ 1.2 mmol/l for ≥ 50% (22/44) of bihourly timepoints; cows were classified as non-HYK if bBHB was ≥ 1.2 mmol/l for < 50% of bihourly timepoints. The HYK cows had bBHB ≥ 1.2 mmol/l for 31.4 ± 6.8 timepoints while the non-HYK cows had bBHB ≥ 1.2 mmol/l for 8.0 ± 3.9 timepoints. We used generalized linear mixed models to analyze concentrations of milk FA over time and differences between HYK groups. The relative percentage of de novo, mixed, and preformed FAs all followed diurnal patterns, however only the yield of preformed FA diurnally cycled, reaching a nadir at 0600 h and peaking at 1400 h. The yield per milking of preformed FA was also greater in the HYK cows than in the non-HYK cows. Oleic acid in milk followed a similar diurnal pattern to the yield of preformed FA, likely driving the cyclical nature of preformed FA. Finally, stearic acid was greater in HYK cows. Our results suggest that FTIR estimates of milk FA offer the potential to provide insight on the energy status of early-lactation cows, and when interested in understanding the absolute concentrations and yields of milk FA, diurnal variation should be considered.

Blood calcium as a prognostic indicator of success after surgical correction of left displaced abomasum

JDS Communications · 2021-04-06 · 4 citations

Subclinical hypocalcemia, a reduction in blood calcium concentrations without apparent clinical signs of milk fever, occurs in 25 to 50% of early-postpartum dairy cows. Research has shown that these cows are at an increased risk of additional early-lactation diseases, including left displaced abomasum (LDA), compared with their normocalcemic counterparts. However, no work has assessed the association of total calcium (tCa) concentration at the time of LDA correction with subsequent milk yield and survival within the herd. Pending future development of an economical and accurate on-farm test for hypocalcemia, the ability to assess LDA prognosis after surgical correction based on precorrection blood tCa concentration is of interest to practitioners. Therefore, our objective was to determine the association of blood tCa concentration at the time of LDA surgical correction with milk yield and herd removal in the 60 d after correction. Nine bovine practitioners, located in New York State, were involved in sample collection from 17 herds for this prospective cohort study. Immediately following LDA diagnosis and before surgical correction, blood samples were collected from 152 dairy cows within the first 30 d in milk for serum tCa determination. The association of tCa with milk yield (n = 110) and herd removal (n = 127) in the first 60 d after LDA surgical correction was analyzed using repeated-measures ANOVA and a generalized linear mixed model, respectively, controlling for parity and days in milk at LDA surgical correction and the random effect of herd or practitioner. We found no evidence to support an association of tCa at time of LDA diagnosis with subsequent milk yield, and when cows were grouped by median tCa into low and high groups (tCa ≤2.1 and >2.1 mmol/L, respectively), subsequent milk production was similar (39.4 ± 1.6 and 40.1 ± 1.4 kg/d for low and high, respectively). Furthermore, we found no evidence to support an association of tCa at time of LDA diagnosis with the odds of herd removal (odds ratio = 0.6; 95% confidence interval = 0.4-1.7). Therefore, our study provided no clear evidence to support the association of tCa at time of LDA diagnosis and correction with either milk yield or herd removal during the 8 wk after correction. However, it did demonstrate low to extremely low tCa concentration in cows with LDA. Whether calcium supplementation would improve health and production outcomes in these cows is unclear and worth investigating further.

Blood calcium as a prognostic indicator of left-displaced abomasum postsurgical correction success

American Association of Bovine Practitioners Conference Proceedings · 2020-09-24

Subclinical hypocalcemia, a reduction in blood calcium concentrations without apparent clinical signs of milk fever, occurs in 25 to 50% of early-postpartum dairy cows. Compared to their normocalcemic counterparts, research has shown these cows are at an increased risk of additional early-lactation diseases, including left-displaced abomasum (LDA). However, no work has assessed the association of total calcium (tCa) concentration at the time of LDA correction on subsequent milk yield and survival within the herd. Pending future development of an economical and accurate on-farm test for hypocalcemia, the ability to assess LDA prognosis post-surgical correction based on pre-correction blood tCa concentration is of great interest to practitioners. Therefore, our objective was to determine the association of blood tCa concentration at the time of LDA surgical correction on milk yield and removal from herd in the 60 d post-correction.

Effect of hyperketonemia on circadian patterns of blood metabolites and milk predicted constituents in dairy cows

American Association of Bovine Practitioners Conference Proceedings · 2020-09-24

Estimates of milk and blood constituents by Fourier-transform mid-infrared (FTIR) analysis of milk offer a promising tool to monitor energy deficit in dairy cows. We sought to explore: 1) diurnal changes in plasma non-esterified fatty acids (NEFA) and β-hydroxybutyrate (BHB) and FTIR estimates of milk BHB and milk predicted blood NEFA (pbNEFA); 2) correlation between plasma BHB and NEFA; and 3) effect of hyperketonemia (HYK) on circadian patterns of plasma and milk metabolites.

Effect of hyperketonemia on the diurnal patterns of energy-related blood metabolites in early-lactation dairy cows

Journal of Dairy Science · 2020 · 19 citations

• Endocrinology
• Internal medicine
• Chemistry

Most dairy cows experience a period of energy deficit in early lactation, resulting in increased plasma concentrations of nonesterified fatty acids (NEFA) and β-hydroxybutyrate (BHB). Our objectives were to determine (1) the diurnal variation in plasma BHB and NEFA, (2) the correlation between plasma NEFA and BHB when accounting for diurnal changes, and (3) the effect of hyperketonemia (HYK) on the diurnal pattern of blood metabolites. Jugular catheters were placed in 28 multiparous Holstein cows between 3 and 9 days in milk, and blood samples were collected every 2 h for 96 h. Cows were retrospectively classified as HYK positive (HYK; n = 13) if they had plasma BHB concentrations ≥1.2 mmol/L for ≥3 study days, or HYK negative (non-HYK; n = 15) if they had plasma BHB concentrations ≥1.2 mmol/L for ≤2 study days. Generalized linear mixed models were used to analyze concentrations of analytes over time and differences in metabolites between HYK groups. The correlation between total plasma NEFA and BHB was analyzed by calculating the area under the curve for plasma NEFA and BHB for all cows. Plasma NEFA reached a peak approximately 2 h before morning feed delivery, falling to a nadir in the late evening. Plasma BHB was at a nadir at the time of morning feed delivery, peaking 4 h later. We observed a strong positive correlation between daily plasma NEFA and BHB. Additionally, HYK cows had greater concentrations of plasma NEFA and BHB than non-HYK cows. The HYK cows also experienced a greater magnitude of change in BHB throughout the day than the non-HYK cows. Our results suggest that the time relative to feeding should be considered when analyzing plasma metabolites, as classification of energy status may change throughout a day.

randomized control trial to evaluate propylene glycol alone or in combination with dextrose as a treatment for hyperketonemia in dairy cows

American Association of Bovine Practitioners Conference Proceedings · 2020-09-24

Postpartum dairy cows undergo a period of energy deficit that can lead to excessive lipolysis and formation of ketone bodies such as β-hydroxybutyrate (BHB). Cows that are hyperketonemic (HYK; blood [BHB] ≥1.2mmol/L) are at greater risk of adverse events during early lactation. Although 300 ml of oral propylene glycol (PG) has been shown to reduce these negative effects, the efficacy of intravenous (IV) dextrose is unclear. Our objective was to investigate the impact of IV dextrose as an adjunct therapy to PG on HYK resolution, disease incidence, and milk yield.

The relationship of excessive energy deficit with milk somatic cell score and clinical mastitis

Journal of Dairy Science · 2020-11-12 · 9 citations

Periparturient cows go through a period of immune suppression often marked by immune cell dysfunction. Further exacerbation of this dysfunction through early-lactation excessive energy deficit (EED) has been associated with increased susceptibility to infectious conditions such as mastitis. Our objective was to explore the association of milk somatic cell score (SCS) and clinical mastitis (CM) diagnosis in cows identified with EED, diagnosed using each of the following: blood and milk β-hydroxybutyrate (BHB), milk predicted blood nonesterified fatty acid (mpbNEFA) concentrations, or milk de novo fatty acid (FA) relative percentages (rel %). We analyzed data collected from 396 multiparous Holstein cows from 2 New York farms in a prospective cohort study. Coccygeal vessel blood samples and composite milk samples were collected twice weekly from 3 to 18 days in milk (DIM) for a total of 4 time points per cow (T1, T2, T3, T4). Blood was analyzed using a hand-held meter, and milk was analyzed using Fourier-transform mid-infrared spectrometry for milk BHB and mpbNEFA concentrations, milk de novo FA rel %, and somatic cell count. Excessive energy deficit was diagnosed as blood BHB ≥ 1.2 mmol/L, milk BHB ≥ 0.14 mmol/L, mpbNEFA ≥ 0.55 mmol/L, or de novo FA ≤ 22.7 rel %, depending on the model. Clinical mastitis cultures were collected from 4 to 60 DIM by on-farm personnel. Incidence of hyperketonemia as determined by blood BHB was 13.4%, and incidence of CM was 23.9%. Separate repeated-measures ANOVA models were developed for each EED diagnostic analyte for parity groups 2, 3, and ≥4 to assess differences in SCS; t-test analyses were similarly used to assess the association of each diagnostic analyte with CM at each time point. For all diagnostic analytes, apart from milk BHB, cows diagnosed with EED tended to have lower SCS than their non-EED counterparts. This was especially apparent at T1 for all parity groups, and at T2, T3, and T4 for blood BHB and mpbNEFA. For EED diagnosis via mpbNEFA, mean SCS were lower in parity ≥4, with a difference in mean SCS between EED and non-EED animals of 0.7 SCS units, equating to a somatic cell count in EED animals approaching half that of non-EED (EED = 67,000 cells/mL, non-EED = 107,000 cell/mL). No important relationships were observed between CM diagnosis and blood BHB, milk BHB, or mpbNEFA. For de novo FA rel %, reductions in this analyte were noted before CM diagnosis at all time points. Although the relationship between EED and CM is still unclear, our findings suggest that cows in EED, diagnosed using blood BHB or mpbNEFA during the first 18 DIM, have a tendency toward lower SCS compared with their non-EED counterparts.

A randomized controlled trial to evaluate propylene glycol alone or in combination with dextrose as a treatment for hyperketonemia in dairy cows

Journal of Dairy Science · 2020 · 17 citations

• Medicine
• Internal medicine
• Animal science

Our objective was to investigate the effect of i.v. dextrose as an adjunct therapy to oral propylene glycol on the resolution of hyperketonemia (HYK; blood β-hydroxybutyrate ≥1.2 mmol/L), disease incidence, and early lactation milk yield. Cows (n = 1,249) between 3 and 16 d in milk (DIM) from 4 New York dairy farms were screened once weekly for HYK for 2 wk. Those with HYK and no previous history of retained placenta, metritis, or HYK were randomly assigned to 1 of 3 treatment groups: 300 mL of oral 100% propylene glycol for 3 d (PG3); 300 mL of oral 100% propylene glycol for 3 d plus 500 mL i.v. 50% dextrose on d 1 (PG3D1); or 300 mL of oral 100% propylene glycol for 3 d plus 500 mL i.v. 50% dextrose on all 3 d (PG3D3). Cows with a blood β-hydroxybutyrate <1.2 mmol/L at initial screening were re-screened the following week and randomly assigned to the above treatment groups if blood β-hydroxybutyrate was ≥1.2 mmol/L. Cows were assessed for post-treatment HYK resolution 1 and 2 wk after initial HYK diagnosis. We collected farm-diagnosed occurrence of adverse events (sold, died, metritis, displaced abomasum, or ketosis) during the first 60 DIM and milk yield data from the first 10 wk of lactation from herd management software. We used mixed-effects multivariable Poisson regression models to assess the risk of post-treatment HYK resolution at 1 and 2 wk following initial HYK diagnosis and adverse event occurrence among treated cows. We used repeated-measures ANOVA to assess differences in average daily milk yield between treatments. The overall HYK incidence was 30.1% (n = 373). Sixty-four percent of cows (n = 237) were assigned to a treatment group in the first week (3 to 9 DIM), and 36% (n = 136) assigned the second week (10 to 16 DIM). The incidence of 1 or more adverse events during the first 60 DIM was 9.4% (n = 35). We found no effect of treatment on risk of post-treatment HYK resolution at wk 1 (PG3 56.9%, PG3D1 45.0%, PG3D3 50.0%) or wk 2 (PG3 60.0%, PG3D1 52.1%, PG3D3 59.5%) following initial diagnosis, or for risk of adverse event occurrence (PG3 7.4%, PG3D1 8.0%, PG3D3 12.6%). Average daily milk yield (mean ± SE) was similar between treatment groups (PG3: 42.7 ± 0.6 kg/d, PG3D1: 42.4 ± 0.6 kg/d, PG3D3: 42.6 ± 0.6 kg/d). The addition of dextrose for 1 or 3 d provided no improvement in resolution of ketosis assessed once weekly, reduction in adverse events during the first 60 d of lactation, or a difference in average daily milk yield during the first 10 wk of lactation.