Algometer Precision for Quantifying Mechanical Nociceptive Threshold When Applied to the Udder of Lactating Dairy Cows.

Objectives of this study were to: (1) quantify the reliability of an algometer for measuring mechanical nociceptive thresholds when applied to the udder of dairy cows; and (2) evaluate whether covariates, such as cow characteristics or time of the day, would influence algometer measurements. This prospective study was performed in a university herd of 37 lactating cows during five consecutive days, involving two raters. Two types of measurement were obtained: one qualitative binary measure (i.e., reaction vs. no reaction) and one quantitative measure presented in kilograms (i.e., mechanical nociceptive threshold, MNT) for the cows that reacted. Kappa statistics were used to investigate test-retest and inter-rater reliability for the qualitative measure, while concordance correlation coefficient (CCC) and limits of agreement plot were used for the quantitative measure. Whether algometer measurements were influenced by several covariates (i.e., time of the day, level of milk production, days in milk, and parity) was then evaluated using logistic or linear regression models, depending on the outcome. The algometer was moderately reliable; there was moderate test-retest reliability (Kappa = 0.53; CCC = 0.58) and inter-rater reliability (Kappa = 0.42; CCC = 0.54). The MNT varied substantially as a function of time of the day and parity. This is the first study reporting reliability of a pressure algometer for quantifying MNT and investigating covariates possibly affecting this measurement when applied to the udder of dairy cows. It is concluded that the use of an algometer for quantifying MNT on the udder is only moderately repeatable and is influenced by extraneous covariates. Its usage in research setting to quantify changes in sensitivity at the udder level should, therefore, be considered very cautiously or it should be further developed

Algometer Precision for Quantifying Mechanical Nociceptive Threshold When Applied to the Udder of Lactating Dairy Cows

Objectives of this study were to: (1) quantify the reliability of an algometer for measuring mechanical nociceptive thresholds when applied to the udder of dairy cows; and (2) evaluate whether covariates, such as cow characteristics or time of the day, would influence algometer measurements. This prospective study was performed in a university herd of 37 lactating cows during five consecutive days, involving two raters. Two types of measurement were obtained: one qualitative binary measure (i.e., reaction vs. no reaction) and one quantitative measure presented in kilograms (i.e., mechanical nociceptive threshold, MNT) for the cows that reacted. Kappa statistics were used to investigate test-retest and inter-rater reliability for the qualitative measure, while concordance correlation coefficient (CCC) and limits of agreement plot were used for the quantitative measure. Whether algometer measurements were influenced by several covariates (i.e., time of the day, level of milk production, days in milk, and parity) was then evaluated using logistic or linear regression models, depending on the outcome. The algometer was moderately reliable; there was moderate test-retest reliability (Kappa = 0.53; CCC = 0.58) and inter-rater reliability (Kappa = 0.42; CCC = 0.54). The MNT varied substantially as a function of time of the day and parity. This is the first study reporting reliability of a pressure algometer for quantifying MNT and investigating covariates possibly affecting this measurement when applied to the udder of dairy cows. It is concluded that the use of an algometer for quantifying MNT on the udder is only moderately repeatable and is influenced by extraneous covariates. Its usage in research setting to quantify changes in sensitivity at the udder level should, therefore, be considered very cautiously or it should be further developed

Incomplete Milking in Early Lactation Does Not Affect Dairy Cows Resting Behaviors: Results from a Randomized Controlled Trial.

The objective of this study was to investigate the effect of incomplete milking during the first 5 days of lactation on the resting behavior of commercial dairy cows. The hypothesis was that the elevated intramammary pressure resulting from milk retained in the udder in incompletely milked cows could lead to a change in lying behavior. This study was a randomized controlled trial in which cows from two farms were randomly allocated into a treatment (n = 18) or a control group (n = 14). Cows in the treatment group were milked incompletely (10-14 L/days) during the first 5 days of lactation, while cows in the control group were milked as usually done on farm. Resting behaviors were recorded with a data logger. Linear mixed models were used to quantify the effects of treatment group on three dependent variables measured between 2 and 14 days in milk: daily duration of lying time (h/d), lying bout frequency (bouts/day), and mean duration of lying bouts (min/bout). There was no significant effect of treatment on lying time. However, the effect of treatment on frequency of lying bouts and on mean lying bout duration varied by parity level. Incompletely milked cows in second parity had a higher number of lying bouts (11.9 vs. 9.2 bouts/day) and shorter mean lying bout duration (57.8 min/bout vs. 66.7 min) than control cows. In third parity or more, the opposite happened. Therefore, our results suggest that an incomplete milking may be slightly problematic for second parity cows and, possibly, slightly beneficial for older cows. Whether the differences observed resulted from a biologic process (discomfort due to the incomplete milking) or from random error will have to be determined by future research

Translactational associations of dry off management, milking activity, and somatic cell count in herds with automated milking systems

The objective of this study was to evaluate associations of dry off management factors, milking activity, and production data and somatic cell count prior to dry off and early in the subsequent lactation of cows milked by automated systems. Data were collected for 342 cows from 5 farms, for 2 milk tests prior to dry off and for the 2 milk tests post-calving. The results suggest that the post-calving milking performance of cows milked by automated systems may be more associated with individual cow traits than with their dry off management.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Associations of housing, management, milking activity, and standing and lying behavior of dairy cows milked in automatic systems

The objective of this cross-sectional study was to describe the housing, feeding management, and characteristics (parity and stage of lactation) of cows on commercial automatic milking system (AMS) dairies and their associations with the standing and lying behavior patterns and milking activity (frequency and yield) of lactating dairy cows. Thirteen AMS herds were enrolled in the study, with an average herd size of 71 ± 30 (mean ± SD; range: 34 to 131) lactating cows. All of the herds used freestall barns, each set up for free cow traffic to the AMS. On-farm measurements were taken to determine stocking density at the freestalls (0.9 ± 0.1 cows/stall; mean ± SD), feed bunk (0.66 ± 0.17 m of feed bunk space/cow; mean ± SD), and AMS units (55 ± 11 cows/AMS; mean ± SD). A random sample of 30 cows/herd was selected to monitor standing and lying behavior for 4 d using electronic data loggers. Times of feed delivery and feed push-up were recorded daily by the herd managers. Milking times, frequency, and yield were automatically recorded by the AMS units. Data were analyzed in a multivariable mixed regression model to determine which herd-level (housing and feeding management) and cow-level (parity, DIM, and milk yield) factors were associated with behavior and milking activity measures. Lying bout lengths were found to be negatively associated with milk yield and tended to be positively associated with more space at the feed bunk. Increased lying duration was associated with cows of lower milk production, increased space at the feed bunk, and increased frequency of feed push-up. Longer postmilking standing durations were associated with cows of higher parity. An association existed between cows milking less frequently when they were further in lactation, were of higher parity, and as stocking density at the AMS (cows/AMS) increased. Milk yield was positively associated with increased space at the feed bunk and higher parity and negatively associated with DIM. From this study, it can be concluded that increased milking frequency may be achieved in AMS herds by reducing stocking density at the AMS unit. Further, in AMS systems, greater milk yield and lying duration may be achieved by ensuring that cows have ample feed bunk space and have their feed readily available to them in the bunk

Canine Food Preference Assessment of Animal and Vegetable Ingredient-Based Diets Using Single-Pan Tests and Behavioral Observation

Knowledge of canine food selection is critical for both the pet food industry and dog owners, since owners want quality foods that are palatable, while fulfilling their pet’s nutritional requirements. There are two common methods for assessing canine food preference: the two-pan test and the one-pan test. Neither test fully accounts for the complexity of the canine feeding experience nor do they provide applicable representations of canine feeding behavior in the home. The objectives of this study were to (1) determine whether dogs display a preference for animal ingredient-based diets when compared with vegetable ingredient-based diets and (2) examine whether dogs experience neophobia when presented with a novel diet. Eight adult Beagles (average age = 24 months, weighing 8–12 kg) were individually fed each of four novel diets in a 4 × 4 replicated Latin square design, with 10-d treatment periods and four dietary treatments. Data were analyzed using a mixed model with repeated measures and significance was declared when p < 0.05. The diets were: animal and vegetable ingredient-based diets, and animal- and vegetable-based ingredients diluted with anhydrous α-d-glucose. The diluted diets were used for a larger study to determine true mineral digestibility. Dogs were fed twice per day (0800 and 1300 h). Behavioral observations were made by video on the first, and last 2 days of each 10-day treatment period of both a.m. and p.m. feedings. Time to consume feed, distraction, hesitation, level of anticipation pre-consumption, and interest post-consumption were recorded. Dogs experienced initial disruptive (neophobic) effects of a novel diet. Neophobia was demonstrated by a decreased (slower) rate of consumption, increased distraction during consumption of the diet, and increased hesitation on the first day of each new diet (p < 0.05). The level of interest post-consumption was highest when dogs consumed the animal-based ingredients diet (p < 0.05). This study presents insights into canine food preference assessment methods that may more accurately represent the dog owner’s experience. Further research is required to determine the minimum length of time necessary to eliminate neophobia to food. In addition, future research should also aim to establish whether interest post-consumption is due primarily to food preference or acute satiety

Domestic cattle (Bos taurus taurus) are motivated to obtain forage and demonstrate contrafreeloading

Domestic cattle (Bos taurus taurus) are adapted to digest high-roughage diets, but in confinement they are commonly fed low-roughage, high-energy diets. This practice may leave cattle with an unfulfilled need to consume forage. A way to quantify motivation is to require animals to work to access a resource. Using this method, we evaluated cattle motivation to obtain forage when fed high- or low-roughage diets during and 30 d before the study. Individual heifers were fed Sudan grass (Sorghum × drummondii) hay (high roughage, n = 6) or a diet with 12% forage (as fed, low roughage, n = 6) in an open feed trough. In a second trough, 200 g/d of Sudan grass hay were fed behind a push gate, to which additional weight was added daily until heifers no longer pushed. We predicted heifers would push heavier weights, show a shorter latency, and spend more time pushing the gate when fed a low- vs. high-roughage diet. Indeed, heifers fed a low-roughage diet pushed the gate immediately after hay delivery (1.7 min) and much sooner than those fed a high-roughage diet (75.7 min). On the day before they no longer pushed the gate, latency for heifers in the low-roughage treatment remained only 3.2 min after hay delivery. The suddenness with which they ceased pushing the next day suggests they were unable to move heavier weights to express their motivation. This may explain why maximum weight pushed and time spent pushing the gate did not differ between treatments. The gate pushing by heifers with unrestricted hay access is the first demonstration by cattle of contrafreeloading: performing work to obtain a resource that is simultaneously available for free. In conclusion, consuming forage is important to cattle and is affected by both their primary diet and an internal motivation to work to obtain feed

Barriers to recording calf health data on dairy farms in Ontario

Establishing accurate illness and treatment rates in dairy calves is crucial, yet calf health records are often incomplete. Thus, the objective of this study was to investigate barriers for dairy farmers for recording calf illnesses and treatments on dairy farms in Ontario, Canada. An online survey was completed by a convenience sample of 88 Ontario dairy farms in 2022, with 34 questions regarding farm demographics, current practices surrounding record keeping and analysis, and factors that would improve recording compliance. Multivariable models were built to assess associations between explanatory variables and the following outcomes: likelihood of making management or treatment protocol changes based on records analysis, factors that would increase the use of electronic recording methods, and whether all calf illnesses and treatments are recorded. Pearson's chi-squared tests were also used to investigate associations between explanatory variables and whether the respondent agreed or disagreed with a proposed reason for why a calf illness or treatment would not be recorded on their farm. Producers had 3.45 times greater odds of recording all antimicrobial treatments if they used a computer software system compared with those that did not. With respect to anti-inflammatory treatments, producers had 3.11 times greater odds of recording these treatments if records were located in the calf barn than elsewhere. Nonfamily employees had 6.08 times greater odds of recording all supportive therapy treatments than farm owners. When calf health records were kept in the calf barn, respondents were less likely to report that illnesses were not recorded due to time constraints (5% vs. 36% if records were elsewhere) or because calf health records were not analyzed (10% vs. 34% if records were elsewhere). On farms that recorded calf treatments in a paper booklet, respondents were more likely to report that treatments were not recorded because calf health records were not analyzed (44% for paper records vs. 21% for other systems). The most commonly indicated factors that would increase recording of illness were recording with a mobile app (27% of respondents) and for the recording system to be easy to use (31% of respondents). Overall, these data indicate that recording may be improved by keeping calf health records in close proximity to the calves and using a recording method that allows for data analysis. An easy-to-use mobile app may also improve recording if it could be used in the calf barn, provide data analytics, and allow for time-efficient data entry

The effect of prepartum negative dietary cation-anion difference and serum calcium concentration on blood neutrophil function in the transition period of healthy dairy cows

Our objectives were to assess the effects of a diet with a negative dietary cation-anion difference (DCAD) before calving on phagocytosis (Pc) and oxidative burst (OB) function of circulating neutrophils, and to determine the associations of serum ionized (iCa) and total calcium (tCa) concentrations with Pc and OB in transition dairy cows. We hypothesized that multiparous cows fed a negative DCAD diet prepartum would have greater iCa and tCa, and thus improved Pc and OB. From 3 wk before expected parturition until calving, 38 healthy multiparous cows from 3 farms were assigned to negative DCAD treatment (TRT; −100 mEq/kg of diet dry matter; n = 21) or a control (CON; 95 mEq/kg of dry matter; n = 17) diet. Each farm was on one treatment or the other at a time, but all farms contributed cows to both groups. Urine pH was measured weekly and in TRT was 6.1 ± 0.8 with 80% of 50 samples <7 and 74% ≤ 6.5. Phagocytosis, OB, iCa, and tCa were measured at d −7, 1, and 4 relative to calving. Median fluorescence intensity for Pc (MFIP) and OB (MFIOB), and the shift of percentage of cells active for Pc (PPc) and OB (POB) were measured in isolated, stimulated neutrophils via flow cytometry. Outcomes were assessed with mixed linear regression models accounting for repeated measures. There were no differences between treatments in the 4 neutrophil function outcomes. Although MFIOB varied over time, there were no interactions of treatment with time for any outcome. Serum ionized and tCa did not differ between TRT and CON. The least squares means ± standard deviation for iCa were: d −7, 1.23 ± 0.12 vs. 1.21 ± 0.12; d 1, 1.07 ± 0.12 vs. 1.02 ± 0.12; d 4, 1.16 ± 0.12 vs. 1.17 ± 0.12 mmol/L for TRT and CON, respectively; and for tCa: d −7 2.39 ± 0.25 vs 2.44 ± 0.31; d 1, 2.01 ± 0.25 vs 1.97 ± 0.31; d 4, 2.33 ± 0.25 vs 2.32 ± 0.31 mmol/L, respectively. The proportion of blood samples with tCa <2.15mmol/L at d −7, 1 and 4 was 5, 76, and 13%, respectively, with no differences between TRT and CON. Correlations of iCa or tCa with each of the 4 polymorphonuclear leukocyte (PMN) function outcomes were weak (r < |0.3|). We did not observe the hypothesized differences in aspects of innate immunity in clinically healthy multiparous cows fed a negative DCAD. We underline that cows that experienced clinical disease were excluded from this study, which is important for interpretation of the results

Domestic cattle (<i>Bos taurus taurus</i>) are motivated to obtain forage and demonstrate contrafreeloading

<div><p>Domestic cattle (<i>Bos taurus taurus</i>) are adapted to digest high-roughage diets, but in confinement they are commonly fed low-roughage, high-energy diets. This practice may leave cattle with an unfulfilled need to consume forage. A way to quantify motivation is to require animals to work to access a resource. Using this method, we evaluated cattle motivation to obtain forage when fed high- or low-roughage diets during and 30 d before the study. Individual heifers were fed Sudan grass (<i>Sorghum × drummondii</i>) hay (high roughage, <i>n =</i> 6) or a diet with 12% forage (as fed, low roughage, <i>n</i> = 6) in an open feed trough. In a second trough, 200 g/d of Sudan grass hay were fed behind a push gate, to which additional weight was added daily until heifers no longer pushed. We predicted heifers would push heavier weights, show a shorter latency, and spend more time pushing the gate when fed a low- vs. high-roughage diet. Indeed, heifers fed a low-roughage diet pushed the gate immediately after hay delivery (1.7 min) and much sooner than those fed a high-roughage diet (75.7 min). On the day before they no longer pushed the gate, latency for heifers in the low-roughage treatment remained only 3.2 min after hay delivery. The suddenness with which they ceased pushing the next day suggests they were unable to move heavier weights to express their motivation. This may explain why maximum weight pushed and time spent pushing the gate did not differ between treatments. The gate pushing by heifers with unrestricted hay access is the first demonstration by cattle of contrafreeloading: performing work to obtain a resource that is simultaneously available for free. In conclusion, consuming forage is important to cattle and is affected by both their primary diet and an internal motivation to work to obtain feed.</p></div