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The American Veterinary Medical Association recognizes castration to be important for both human and animal safety. Lidocaine delivered through-the-needle has been shown to be effective at reducing cortisol response to castration, but this method has drawbacks for both animals and caretakers. As such, a study was conducted to examine the potential benefits of lidocaine delivery using a pneumatic needle-free device immediately before standing bovine castration. Twelve Holstein bulls weighing 400.7 ± 39.5 kg (mean ± standard deviation) were enrolled. Bulls were allocated to receive a local anesthetic block of 2% lidocaine for surgical castration by traditional needle injection or by needle-free injection. Outcomes were collected out to 48 h postcastration. Outcome variables included plasma cortisol concentrations, visual analog scale scores for pain, medial canthus temperatures as measured using infrared thermography, pressure mat changes, and chute defense scores. A time effect was observed for cortisol, visual analog scale scores, infrared thermography temperatures, and some pressure mat outcomes. No statistically significant differences between lidocaine delivery methods were observed, but further research is needed to build upon this small dataset.

The use of zwitterionic-hydrophilic interaction liquid chromatography (Z-HILIC) columns for analysis of underivatized analytes has allowed simpler sample preparation of bovine plasma for sensitive and selective analysis, when coupled with mass spectrometry (MS). The objective of this study was to evaluate and validate this analytical technique to measure AA and metabolites in bovine plasma at 2 deproteinization times. A robust method using Z-HILIC coupled to a triple quadrupole MS (TQMS) was evaluated and validated to quantitatively analyze 19 AA using isotope dilution and 8 AA metabolites qualitatively in bovine deproteinized plasma. The timing of deproteinization was investigated to determine if plasma should be deproteinized upon collection (on-site) or immediately before analysis (in-lab). Analytes were separated using a Z-HILIC column in a 21 min run and analyzed with a TQMS in positive electrospray ionization for identification and quantification. The method was validated for standard curve linearity, limits of detection (LOD) and quantification (LOQ), intra- and interday precision (% coefficient of variation; CV), recovery (%), and freeze-thaw stability (% CV) after 1 mo. Coefficients of determination (R²) were over 0.993, and LOD and LOQ were below measured values for all AA. The CV for the intraday and interday precision were below 18%, except for cystine (Cys2) and Orn in-lab. Recoveries on-site and in-lab ranged from 75% to 120% for all analytes except Cys2 in-lab. Most analytes were stable after 1 mo of freezing regardless of deproteinization timing, CV <25%, except for hydroxyproline (Hyp). The concentration of Cys2 was affected by deproteinization in-lab compared with on-site, and even though Glu and Hyp were different between the 2 deproteinization timings, the concentrations between the 2 timings were within the standard deviation.

Our previously published companion papers demonstrated improved production performance and energetic metabolism in cows fed diets with increased propiogenic potential in early lactation. Study objectives were to further explore effects of dietary starch content and monensin on hepatic gene expression of key enzymes related to gluconeogenesis and fatty acid metabolism in early lactation. From d 1 to 21 postpartum, primiparous (n = 16) and multiparous (n = 33) Holstein cows were fed a high (HS; 26.2% starch, 34.3% neutral detergent fiber, 22.7% acid detergent fiber, 15.5% crude protein) or low (LS; 21.5% starch, 36.9% neutral detergent fiber, 25.2% acid detergent fiber, 15.4% crude protein) starch diet with a daily topdress containing either 0 (Con) or 450 mg/d monensin (Mon). Cows were randomly assigned to treatment. Liver biopsies were obtained from cows on d 7 postpartum for DNA and RNA quantification and mRNA expression analysis. In primiparous cows, Mon supplementation decreased CPT1A expression relative to controls, whereas in multiparous cows Mon increased its expression. Cows fed HS and Mon tended to have decreased HMGCS2 expression relative to cows fed HS and Con. In multiparous cows, Mon supplementation tended to increase PC and PCK1 expression relative to controls. Correlation analysis was performed for all gene expression variables. Overall, relationships were similar in directionality and magnitude between cows fed HS and LS and Con and Mon. However, for cows fed Con there was a positive relationship between HMGCS2 and PC and HMGCS2 and PCK1, whereas for cows fed Mon there was no relationship. There was a similar lack of relationship between HMGCS2 and PC for cows fed HS. Overall, results support changes in performance and energetic metabolism reported in our companion papers, indicating that cows fed diets of different starch content in early lactation with Mon supplementation throughout the transition period had alterations in hepatic gene expression consistent with increased hepatic propionate supply.

Around parturition, dairy cows inevitably and perhaps necessarily experience some degree of systemic inflammation, but when excessive or dysregulated, it may contribute to health disorders. As immune activation decreases blood Ca, greater extracellular Ca availability may potentiate or sustain inflammation. We hypothesized that in clinically healthy multiparous cows, postpartum administration of supplemental Ca would increase serum concentrations of inflammatory markers. The objective of this randomized controlled trial was to investigate a possible effect of supplementing calcium (Ca) on postpartum systemic inflammation in dairy cows. Healthy cows (n = 101) from 2 commercial dairy farms in Ontario calving into parity 2, 3, or 4 were enrolled. Cows were blocked by parity and randomly assigned to receive an oral bolus of Ca (42 g of Ca) within 12 h after calving and a second bolus 12 h later (TRT; n = 51), or no Ca supplementation (CON; n = 49). Concentrations in serum of total Ca (tCa), haptoglobin (Hp), and albumin (ALB) were assessed at d 0 (within 12 h postpartum), 0.5 (12 h later), 1, 2, 4, 6, and 8 postpartum; ionized calcium was assessed at d 0, 0.5, 2, and 4, and lipopolysaccharide-binding protein (LBP) and serum amyloid A (SAA) were assessed at d 0, 2, and 4. Multivariable linear regression models of each outcome accounting for repeated measures included treatment, parity (2 vs. 3 or 4), farm, sampling day, baseline concentration (d 0), and interactions of treatment with farm, parity, and day. Results are presented as least squares means and 95% confidence intervals. Concentration of tCa tended to be greater at d 0.5 (TRT 2.07 mmol/L [2.03–2.12]; CON 2.01 [1.96–2.06]) but was lesser at d 2 (TRT 2.18 [2.13–2.23]; CON 2.27 [2.23–2.32]) in TRT than CON cows. Concentrations of LBP were greater in TRT (2.28 ng/mL [2.06–2.50]) than CON (1.99 [1.77–2.21]) in parity 2, but not different in older cows (TRT 2.28 ng/mL [2.06–2.50]; CON 1.99 [1.77–2.21]). Concentrations of SAA were greater in TRT than CON cows at d 2 (TRT 135 ug/mL [124–146]; CON 114 [75–106]). Treatment had no effect on ALB or Hp. In clinically healthy cows, oral Ca supplementation had a small transient effect on blood tCa and little indication of increasing inflammation based on the analytes evaluated.

Oxygenated polyunsaturated fatty acids (oxylipins) are important mediators of inflammation ranging from pro- to anti-inflammatory actions. Research investigating differences in the oxylipin profile of dairy cows suffering from different degrees of systemic inflammation in the early postpartum period is lacking and can help advance knowledge on potential mechanisms leading to excessive inflammation. The objective of this preliminary study was to evaluate the plasma oxylipin profile of cows classified in 1 of 4 systemic inflammation categories based on plasma haptoglobin (Hp) concentrations assessed on days in milk (DIM) 1, 2, 3, 4, 5, and 7, in addition to the presence or absence of metritis within 10 DIM, and of cows without any clinical diseases within 21 DIM. Groups were classified as follows: (1) cows with a peak Hp concentration ≤3 DIM (EarlyHp) and diagnosed with metritis; (2) cows with a peak Hp concentration 3 < DIM ≤7 (LateHp) and diagnosed with metritis; (3) cows suffering from persistently elevated Hp concentrations assessed on DIM 4 and 7 while remaining apparently healthy during the first 21 DIM (PersistentHp); and (4) apparently healthy cows not suffering from persistently elevated Hp concentrations (LowHp). Six cows from each category were randomly selected from a plasma bank of a parent cohort study including 380 multiparous cows. Plasma samples on DIM 1 and 2, 3 and 4, and 5 and 7 were proportionally pooled to create 3 samples per cow for lipidomic analysis (i.e., pool 1 = DIM 1 and 2; pool 2 = DIM 3 and 4; pool 3: DIM 5 and 7). Statistical analyses were performed using SAS v9.4 (SAS Institute Inc.) and least squares means adjusted for multiple comparisons using the Tukey-Kramer test. Comparisons for EarlyHp and LateHp were only performed on pooled samples from DIM 1 and 2 (i.e., before metritis diagnosis). EarlyHp cows had decreased concentrations of 9(S)-HOTrE compared with LowHp cows of DIM 1–2 pooled samples. LateHp cows had decreased concentrations of 9(10)-DiHOME compared with LowHp cows. Next, we sought to investigate whether cows classified as PersistentHp had time-dependent differences in oxylipin profile versus LowHp cows. PersistentHp cows had decreased concentrations of 19(R)-HETE compared with LowHp cows in a time-dependent manner (only in pooled samples from DIM 5 and 7). Our results identified oxylipins of interest that warrant further investigation to elucidate their in vitro and in vivo functions in the postpartum inflammatory process of dairy cows.

Details from every mixing load of total mixed ration (TMR) fed to ∼19,000 cows distributed in 92 pens from 21 farms, along with individual milk yield of each cow in every pen and farm, were collected from a feeding and management system (algoMilk; www.algomilk.com) between 2020 and 2022 on a daily basis to assess the impact of quality of mixing TMR on animal performance. Divergence between expected and actual amounts of ingredients mixed in every load was calculated and expressed as a percentage relative to expected amounts. Ingredients were classified as (1) energy grains (i.e., corn, wheat), (2) protein sources (i.e., soybean meal, canola meal), (3) hays (i.e., alfalfa hay), (4) grain silages (i.e., corn silage), (5) nongrain silages (i.e., alfalfa silage), (6) minerals (i.e., salt, sodium bicarbonate), and (7) straw (i.e., wheat straw). Milk yield was averaged within farm and pen on a weekly basis, and mixing divergences were also averaged by load or by ingredient type and week within pen and farm. The weekly standard deviation (SD) of mixing divergences was calculated for every pen and farm. The average divergence of the total amount of TMR prepared was 1.52 ± 0.017% (mean ± SD), which means that, in general, mixing errors were caused by adding an excess of one or more ingredients. Energy grains (1.20 ± 0.037%), grain silages (1.78 ± 0.023%), hays (2.29 ± 0.044%), and protein sources (1.82 ± 0.043%) were mixed in excessive amounts (mean ± SD), whereas nongrain silages (−1.5 ± 0.037%), molasses (−3.05 ± 0.067%), minerals (96.9 ± 0.084%), and straw (−0.6 ± 0.063%) were mixed (mean ± SD) in lower amounts than expected. Divergence in the total amount of TMR was weakly quadratically (concave) correlated (R² = 0.04) with milk yield. Similarly, divergence in the amounts of grains, protein sources, hay, silages, minerals, and molasses mixed in the TMR wagon in relation to the formulated ration was also weakly and quadratically (concave) with milk yield. Minimizing mixing errors may have positive effects on milking performance.

This experiment was conducted to evaluate the effects of feeding a Bacillus-based direct-fed microbial (DFM) on performance, nutrient digestibility, rumen fermentation, and metabolic response of lactating dairy cows. Sixty-eight lactating (50 ± 6 d in milk) Holstein-Friesian (n = 20) and Swedish Red (n = 48) cows were enrolled to a 15-wk experiment. Cows were blocked by breed, lactation number, and days in milk and, within blocks, assigned to 1 of the 2 treatments: (1) basal partial mixed ration (PMR) without DFM (n = 34; CON) or (2) basal PMR with the addition of 3 g/head per day of a DFM containing Bacillus licheniformis and Bacillus subtilis (n = 34; DFM). The DFM was mixed in a protein pellet, whereas the CON group was fed the same pellet without DFM (1 kg/cow per day). The PMR contained 53% clover grass silage and 47% compound feed plus 3 kg of a concentrate (dry matter basis) offered during milking. Milk yield and production efficiency were recorded daily, whereas milk samples were collected for 24 h every second week of the study for milk composition. During the experimental period, fecal, rumen fluid, and blood samples were collected from each cow for apparent nutrient digestibility, rumen fermentation, and metabolic responses, respectively. All data were analyzed using the MIXED procedure of SAS. No treatment effects were observed on cows final body weight and daily dry matter intake. However, cows fed DFM had a greater milk yield, milk production efficiency, lactose and total solids yield, and also tended to have a greater energy-corrected milk production efficiency and milk protein yield. No significant differences were observed on nutrient digestibility and total volatile fatty acids, but molar proportion of acetate was greater for cows fed DFM. In contrast, molar proportion of propionate was greater and butyrate tended to be greater for CON. Cows fed DFM had greater mean plasma insulin-like growth factor-I (IGF-I), but no differences were observed for plasma glucose and insulin. In summary, supplementing a Bacillus-based DFM benefited productive responses of lactating dairy cows, while also modulating rumen fermentation and serum IGF-I.

The objectives were to evaluate the effects of a 4-strain direct-fed microbial (DFM) on gastrointestinal tract (GIT) permeability and inflammation during feed restriction (FR) in heifers. Holstein heifers (n = 32; mean ± standard deviation; 295 ± 25 kg body weight; 287 ± 17 d of age) were used in an experiment conducted in 2 replicates (16/replicate). Heifers were randomly assigned to 1 of 2 top-dressed dietary treatments: (1) control (CON; 10 g/d dried lactose; n = 16) or (2) DFM containing a commercial blend of Lactobacillus animalis, Propionibacterium freudenreichii, Bacillus licheniformis, and Bacillus subtilis at 11.8 × 10⁹ cfu/d (PRO; 10 g/d 4-strain DFM; n = 16). The trial consisted of 2 experimental periods (P): P1 (14 d) served as baseline for P2 (5 d), when all heifers were restricted to 40% of their P1 dry matter intake (DMI). On P1 d 12 and P2 d 2 and 5, GIT permeability was evaluated using oral chromium (Cr)-EDTA. By design, FR decreased DMI (60%) and body weight (∼18 kg) in all heifers. Regardless of treatment, during FR, all heifers had decreased circulating glucose, β-hydroxybutyrate, insulin, and l-lactate (4, 14, 45, and 19%, respectively), but increased nonesterified fatty acids, serum amyloid A, and haptoglobin (3.0-, 1.7-, and 5.0-fold, respectively). Circulating white blood cells, neutrophils, lymphocytes, and basophils decreased (4, 7, 5, and 6%, respectively), whereas eosinophils increased (41%) during P2 irrespective of dietary treatment. Circulating IFN-γ inducible protein-10 increased (23%) during FR compared with P1 regardless of treatment. Plasma Cr area under the curve increased in all heifers on d 2 and 5 (10 and 14%, respectively) of P2 relative to P1, but this was unaltered by dietary treatment. In summary, FR compromised GIT barrier function and stimulated an inflammatory response, but this did not appear to be ameliorated by PRO.

In the dairy cattle sector, the number of crossbred genotypes increased in the last years, and therefore, the need for accurate genomic evaluations for crossbred animals has also increased. Thus, this study aimed to investigate the feasibility of including crossbred genotypes in multibreed, single-step genomic BLUP (ssGBLUP) evaluations. The Council of Dairy Cattle Breeding provided more than 47 million lactation records registered between 2000 and 2021 in purebred Holstein and Jersey and their crosses. A total of 27 million animals were included in the analysis, of which 1.4 million were genotyped. Milk, fat, and protein yields were analyzed in a 3-trait repeatability model using BLUP or ssGBLUP. The 2 models were validated using prediction bias and accuracy computed for genotyped cows with no records in the truncated dataset and at least one lactation in the complete dataset. Bias and accuracy were better in the genomic model than in the pedigree-based one, with accuracies for crossbred cows higher than those of purebreds, except for fat yield in Holstein. Our study shows that genotypes for crossbred animals can be included in a ssGBLUP analysis with their purebred ancestors to estimate genomic estimated breeding values in a single run.