Dairy producers’ colostrum practices, marketing, and attitudes toward male dairy calves

Optimal early-life care of surplus calves born on dairy farms is critical for health and welfare. This cross-sectional study aimed to describe the marketing practices of male dairy calves, differences in the co-lostrum management between male and female calves on dairy farms, and the relationship between discrepant colostrum practices and dairy producers’ attitudes toward male calf care. US dairy producers (n = 1,000) in the states of Florida, Michigan, Ohio, Vermont, and Wisconsin were selected using stratified random sampling. A questionnaire containing questions about farm demographics, colostrum management (including quantity and timeliness of colostrum delivery), and producers’ attitudes toward male calf care was mailed in February 2021. Attitudes toward male calf care were assessed using 5-point Likert scales for 10 statements regarding perceptions of the value of male calves and barriers in providing optimal care. Producer responses to questions about the quantity and timeliness of co-lostrum delivery between male and female calves were compared using a non-parametric Wilcoxon rank-sum test. Multivariable logistic regression models were used to investigate the association between differences in colostrum management and producers’ attitudes. By May 2021, 953 surveys were delivered and 315 (33.1%) were returned with complete responses. Most producers (>90%) reported feeding equal volumes of colostrum and performing the first post-birth feeding within a similar time frame for male and female calves. However, compared with females, male calves had a longer delay to the first colostrum feeding. Approximately 40% of producers marketed their male calves through auctions, and over half (54.6%) of farms sold the male calves between 3 and 10 d of age. Large farms (≥500 lactating cows) were found to market male calves at a younger age (≤3 d of age). Most producers (>78%) believed their male calves were receiving optimal care and did not consider the workload and financial costs as obstacles to providing good care to male calves. However, those who viewed the workload as an obstacle to good care and produced organic products were marginally more likely to feed a lower volume of colostrum to male calves in the first feeding after birth. These findings suggest that interventions to improve colostrum practices should be more broadly targeted to all calves born on dairy farms, and that age at transport is markedly different between large and small farms.


INTRODUCTION
Optimal early-life care enables good calf health, welfare, and productivity (Windeyer et al., 2014).On dairy farms, a portion of calves, often males or infertile females, cannot be used to replace the milking herds (i.e., surplus calves).Since surplus calves provide limited profitability to farms, they are often marketed within the first 2 weeks of life (Windeyer et al., 2014;Renaud et al., 2018bRenaud et al., , 2020)).The low value and earlylife sale of surplus calves may contribute to suboptimal neonatal care on the source dairy farm and contribute to higher morbidity and mortality in veal and dairybeef production (reviewed by Creutzinger et al., 2021).
Colostrum feeding management (e.g., the source, quality, and volume of colostrum delivered to calves, and the timeliness of the first colostrum feeding after the birth) is considered a critical factor in the successful transfer of passive immunity and calf health (Uetake, 2013;Fischer et al., 2018;Godden et al., 2019;Hue et al., 2021).Failed transfer of passive immunity (FTPI) from the dam to calves is associated with increased morbidity, mortality, duration of disease, pathogen shedding, and reduced growth in preweaning calves (reviewed by Bandlow et al., 2023).However, suboptimal colostrum feeding practices for surplus calves have been reported on dairy farms and is associated with an increased incidence of FTPI.For example, Fecteau et al. (2002) reported higher counts of mastitis pathogens in colostrum offered to male calves, suggesting a higher pathogen exposure in male calves compared with females.A previous study on Canadian dairy farms reported that producers provided different sources of colostrum, lower quality and volume of colostrum, and longer time from birth to the first colostrum feeding for male calves (Renaud et al., 2020).These practices are often related to producers' distribution and prioritization of resources regarding the time, workload, and costs (Wilson et al., 2021).
In addition to poor colostrum management practices, surplus calves often undergo health and welfare challenges during marketing (Wilson et al., 2020a;Creutzinger et al., 2021).In Canada, surplus calves were often marketed at 3 to 7 d of age and experienced at least 12 h long-distance transportation, leading to an increased risk of health problems (e.g., navel disease, nasal discharge, depression) upon arrival (Wilson et al., 2020a;b).Although interventions such as regulating the minimum calf age for marketing/transportation have been a trend worldwide (National Animal Welfare Advisory Committee, 2018; Canadian Food Inspection Agency, 2019; European Union, 2019), a similar regulatory approach to ensure robust calf health and immunity before marketing has not been implemented for the US dairy industry.Given the potential impact on health and welfare, additional understanding of male calf marketing practices in the US is necessary.
Dairy producers' attitudes can influence their onfarm practices and act as predictors of future behavior (Kraus, 1995;Willock et al., 2008;Rahelizatovo and Gillespie, 2015).Producers' attitudes can be influenced by their background, farming experience, and the opinions of relevant stakeholders (Pempek et al., 2017).However, producers' specific perspectives on the value  1. Final multivariable logistic regression analysis of dairy producers' characteristics and attitudes associated with feeding less colostrum (n = 11) to male calves compared with females

Outcome
Variable Odds ratio a (95% CI b )

P-value
Whether male calves were fed with less volume (L) of colostrum than females in the first feeding (Yes/No).
Attitude on male calf care c "My male calves are receiving optimal care."1.18 (0.47 -3.79) 0.74 "I cannot provide the level of care I wish to provide to male calves due to the financial cost." a Odds ratio represents the times of odds of providing less colostrum to male calves than females, i.e., "Yes" of the binary outcome.b Profile likelihood 95% confidence interval.c Survey participants were asked to rate their level of agreement to statements among "Strongly disagree," "Disagree," "Neither agree nor disagree," "Agree," "Strongly agree."The levels of agreement were numerically converted into scores as 1 "Strongly disagree" to 5 "Strongly agree," and included in the multivariable model as continuous variables.
and management of surplus male dairy calves have not been well documented and may help explain variation in the early-life care of surplus calves, including colostrum management.Therefore, the objectives of this study were to: 1) describe producers' marketing practices for male calves born on dairy farms, 2) compare colostrum practices between male and female calves, and 3) characterize dairy producers' attitudes toward male calf care and identify associations with discrepant colostrum practices for male and female calves.

MATERIALS AND METHODS
This study was reported following the Strengthening and Reporting of Observational Studies in Epidemiology -Veterinary Extension (STROBE-Vet) statement (O'Connor et al., 2016) and a Consensus-based Checklist for Reporting of Survey Studies (CROSS) guidelines (Sharma et al., 2021).

Ethics
This study was approved by the Institutional Review Board (IRB) at The Ohio State University (Ohio, USA) (IRB# 2021E0065).

Questionnaire design and distribution
The self-administered questionnaire (available at https: / / doi .org/ 10 .5281/zenodo .7019271)used in this study was part of a larger survey addressing animal welfare and antimicrobial treatment practices in dairy production systems.Demographics of dairy producers (e.g., age, education, farming experience) and farms (e.g., herd housing, milking system, veterinary visit frequency) were collected with 12 multiple-choice questions.On-farm calf colostrum management and marketing practices were collected by 9 multiple-choice and 9 open-ended questions.To measure attitudes,  2. Final multivariable logistic regression analysis of dairy producers' characteristics and their attitude to male calf care associated with longer delay from birth to the first colostrum feeding (n = 18) in male calves compared with females.One subject was excluded as an outlier (Cook's Distance = 0.17) to improve model fit

Outcome
Variable Odds ratio a (95% CI b )

P-value
Whether male calves received the first colostrum feeding later than females (Yes/No).
Attitude on male calf care c "My male calves are receiving optimal care."1.05 (0.39 -2.87) 0.92 "I cannot provide the level of care I wish to provide to male calves due to the financial cost."0.45 (0.14 -1.43) 0.18 "I would rather my male calves go to a dairy-beef grower than a veal grower.: 1.02 (0.54 -1.94) 0.95 "A price premium would influence my decision to give male calves more or higher quality colostrum" Odds ratio represents the times of odds of providing first colostrum feeding to male calves later than females, i.e., "Yes" of the binary outcome.
b Profile likelihood 95% confidence interval.c Survey participants were asked to rate their level of agreement to statements among "Strongly disagree," "Disagree," "Neither agree nor disagree," "Agree," "Strongly agree."The levels of agreement were numerically converted into scores as 1 "Strongly disagree" to 5 "Strongly agree," and included in the multivariable model as continuous variables.
Surveys were mailed to dairy producers in February 2021 and contained a paper-based questionnaire, consent statement, a USD $2 bill incentive, and a postage-paid return envelope.The questionnaire was also digitized and uploaded to an online survey platform (Qualtrics ® XM Platform, Qualtrics International Inc., Seattle, WA), and accessible by scanning a Quick Response (QR) code on the paper version of the questionnaire.Thus, survey recipients were given options to complete and return the questionnaire on paper or online.Responses were anonymous, and study IDs were assigned in the order surveys were returned.Two reminder postcards were mailed to all survey recipients in March (i.e., one month after the initial questionnaire mailing) with the questionnaire QR code attached.

Selection of dairy producers
Licensed grade A dairy producers in 5 US states (Florida, Michigan, Ohio, Vermont, and Wisconsin) were eligible to participate in this study.These states were selected because of the substantial population of dairy cattle, the varied farm demographics between states, and the availability of state producer lists of grade A farms from the respective State Departments of Agriculture.A total distribution list of 1,000 producers was calculated to garner 450 usable survey responses (i.e., 45% expected response rate, Habing et al. (2016)), which would provide sufficient statistical power (1 -β = 0.8) to identify significant (α = 0.05) differences between 2 comparison groups assuming 1) the risk factor would be equally distributed between 2 groups and 2) 20% and 31% of the 2 groups would report the outcome of interest.Proportionate stratified sampling was used to select 1,000 producers from each of the 5 states (i.e., 5 strata) using Equation 1.For all farms, the probability of being selected is the proportion of total sample size (1,000) to the total number of grade A farms in 5 states.

Number of selected farms in state A = 1,000 × Number of total farms in state A
(1)

Number of total farms in 5 states
Data processing and statistical analysis.Physically and electronically returned surveys with complete responses were manually entered into an online database (Access ® , Microsoft ® Corp., Redmond, WA) by the research team and later exported into Excel ® spreadsheets (Microsoft ® Corp., Redmond, WA).Data entry error checking was performed in Access ® using pre-determined query criteria and drop-down menus for numeric and multiple-choice questions, respectively.Verified databases were imported into SPSS ® Statistics (IBM ® , version 28.0) and R 4.2.2 (R Core Team, 2022) for data analyses.Missing responses were excluded for each question, resulting in different number of available data for corresponding analyses.
To reach our first objective, the source and delivery method of colostrum for male and female calves, and the marketing strategy of male calves were reported using kernel density histograms.The histograms show Proposed causal diagram for the relationships between measured herd and producer characteristics, producer's attitudes toward male calf care practices, and whether the male calves received poorer colostrum feeding practices than females.
the distribution of shape of data with the wider/thinner section representing a higher/lower probability of producers reporting a certain percentage of calves for each category.
For the second objective, differences in the volume (quarts) of colostrum fed and the time (hours) from birth to the first colostrum feeding between male and female calves were compared using a nonparametric, paired Wilcoxon signed rank test, as the data did not meet the assumption of normality (Rey and Neuhäuser, 2011).The volume data were analyzed in quarts as according to the questionnaire wording, but results were converted and reported in liter (1 quart = 0.946 L), following the journal guidelines.Where an upper/lower boundary of numbers was provided for volume of colostrum or time to colostrum feeding, the boundary was used for analysis (e.g., 4 quarts for " ≥ 4 quarts," 12 h for " ≤ 12 hours").In addition, for range of numbers   (e.g., 6 -10 quarts) provided, the mean of the range was used (e.g., 8 quarts for "6 -10 quarts").Responses in text (e.g., "as much as they will drink," "depends on calf size") were excluded for quantitative analysis.The association between the number of lactating cows and the marketing age of male calves was investigated using the Fisher's Exact Test.
To achieve the third objective, producers' level of agreement with 10 male calf care statements (Q23) was numerically converted into scores as 1 "Strongly disagree" to 5 "Strongly agree" and descriptively summarized.Responses to one statement regarding on-farm male calf euthanasia was excluded from the analysis due to redundancy with another questionnaire item (Q25).In addition, dairy producers' marketing routes of on farm male calves and the importance of stakeholders' calf management opinions (Q25 and Q30) were descriptively summarized.
Logistic regression models were used to test the hypothesis that the producers' levels of agreement (i.e., attitudes) on 9 male calf care statements were associated with discrepant colostrum management between male and female calves.Two farm-level multivariable logistic regression models were created for the binary outcomes: 1) whether male calves received lower volume of colostrum than females for the first feeding, and 2) whether male calves received the first colostrum feeding later than females.The score of agreement on 9 statements was included in both models as 9 continuous independent variables (i.e., predictors).To provide generalizable estimates to the commercial dairy industry, producers milking less than 20 cows per day were excluded from the analysis.Herd characteristics (e.g., state, the number of lactating cows, housing, milking system) and producer characteristics (e.g., age, on-farm role, education, Supplementary material 1 [S1]) were identified as likely confounders using a causal diagram (Figure 1, created by DAGitty [Textor et al., 2016]) and included as fixed effects in both models.The number of lactating cows (Q7) was categorized into 3 groups (S1) representing herd sizes because of the lack of linear relationship with the 2 logit-transformed outcomes.For certain questions (S1), categories with a small number or no responses were combined with others to avoid the issue of complete separation and parameter inflation in the regression models.Multicollinearity was further controlled using Cramér's V, and one of 2 strongly correlated confounding variables (Cramér's V >0.25) was excluded from modeling (Akoglu, 2018).The effect of each predictor and confounding variable is reported as an odds ratio with a profile likelihood based 95% confidence interval, indicating the fold change of odds of feeding less colostrum or feeding colostrum later to male calves compared with females.For modeling results, Wald Chi-squared test P-values <0.05 were considered statistically significant while 0.05 ≤ P-values <0.10 indicated trends.Influential outliers were detected using the Cook's distance (Stevens, 1984) and models' goodness of fit was assessed by the Hosmer-Lemesbow test (Hosmer and Lemesbow, 1980) using the ResourceSelection package (Lele et al., 2023).Subjects were excluded from the model analysis based on the Cook's distance (from largest to smallest) until the model fit was adequate (P ≥ 0.05, Hosmer-Lemesbow test).

Marketing of male calves
Producers most frequently marketed male dairy calves between 3 and 7 d of age (45.8%; 137/299) while only 14.7% (44/299) of farms sold their male calves within 3 d of age (Table 3).In total, 72.2% (216/299) of farms sold their calves before 10 d of age while 45.2% (135/299) kept male calves on farms for more than a week.Overall, approximately 50% of small (<250 lactating cows; n = 235) and medium (250 -499 lactating cows; n = 27) farms sold their male calves at 3 to 7 d of age, whereas 48% of large (≥500 lactating cows; n = 29) farms sold before 3 d of age (Table 4).For all participating producers and those marketing their male calves before weaning, an inverse association between the number of lactating cows and the marketing age of male calves was observed (P < 0.05).That is, the larger the lactating herd, the younger the calves were when they were sold.
Approximately 40.3% (118/293) and 23.2% (68/293) of dairy producers marketed >50% of their male calves through auctions and sales to other farms, respectively (Figure 5), and only 3 producers reported euthanizing >50% of male calves after birth.The distribution of dairy producers by calf marketing methods, size of lactating herds, and the state of dairy farms was summarized in Table 5.Furthermore, the marketing methods were found to be associated with the size of lactating herds (P = 0.02) and the located state (P < 0.001).5.The distribution of participating dairy producers on the primary marketing methods for >50% of male calves, the number of lactating cows, and the state of dairy farms Male calves were often delivered from the farm by external transportation services (74.0%; 208/281) and, therefore, producers usually never received feedback from buyers (55.6%; 160/288).However, 37.9% (47/124) of producers reported making changes in male calf care practices according to feedback from buyers.Table 5 summarizes the distribution of respondents by the lactating herd size, state of dairy farm, calf marketing method, whether calves were delivered by on-farm personnel, the reception of calf buyers' feedback, and whether producers made practice changes according to calf buyers' feedback.In addition, the state of dairy farms was associated with the reception of feedback from calf buyers (P < 0.001), where most producers in Florida and Michigan (>70%) received feedback from their calf buyers while those in Vermont and Wisconsin mostly did not (>65%).
Additionally, over half of the producers (61.3%; 193/315) provided calf care themselves or through their family members rather than farm employees.Regarding making decisions on calf care practices, 75% of producers reported that opinions from their herd veterinarians were important, which was higher than the importance of opinions from other stakeholders (e.g., calf buyers, the public, other dairy producers) (Figure 6).

Producers' attitudes on male calf care and their associations with colostrum management
Overall, most producers (89% agreed or strongly agreed) believed their male calves were receiving optimal care and agreed or strongly agreed (95%) that they were responsible for providing optimal on-farm male calf care (Figure 4).Over half of producers (57% agreed or strongly agreed) considered male calves as The distribution of percentages of calves reported by survey respondents of male and female calves that received colostrum from 6 sources (Q14 and Q19).The kernel density histogram shows the distribution shape of data with the wider section representing a higher probability of producers reporting a given percentage of calves and thinner sections corresponding to a lower probability.
an asset to the dairy industry and believed their male calves were well taken care of (89% agreed or strongly agreed).In contrast, producers mostly disagreed that they were not able to provide optimal male calf care due to financial costs (80% disagreed or strongly disagreed) and workload (79% disagreed or strongly disagreed).
Strong correlations (Cramér's V >0.25) were found among potential confounders (S3).Overall, age of the producer, herd size (number of lactating cows), producing organic products, and the percentage of dairy animals bred with beef sires/semen were not mutually correlated (S3) and, therefore, were each considered for inclusion in the final models.One subject was excluded from the model investigating the likelihood of longer delay in the colostrum feeding for male calves to ensure adequate model fit.In the final models, there were no associations between discrepant colostrum management between male and female calves (volume [n of fitted observations = 185], timeliness of colostrum feeding [n of fitted observations = 184]) and the producers' attitudes toward male calf care, controlling for selected confounders (Table 1 and 2).Producers that strongly believed they could provide the level of male calf care as they wished regardless of high workload were marginally less likely to feed a lower volume of colostrum to male calves compared with females (odds ratio [OR] = 0.43, 95% CI: 0.15 -1.08, P = 0.08).Likewise, there was a marginally smaller likelihood of feeding a lower volume of colostrum to male calves compared with females among conventional producers compared with organic producers (OR = 0.17, 95% CI: 0.02 -1.25, P = 0.07).Associations were not reported for other producers' attitudes and demographics (e.g., age, number of lactating cows, and percent of dairy animals bred with beef sires/semen) in both models (Table 1 and 2).

DISCUSSION
Male calves within dairy-beef and veal production systems often experience high morbidity and mortality, and it is important to understand the early-life care on dairy farms that may contribute to these negative health outcomes.The current study aimed to describe US dairy producers' marketing strategies for male calves, compare their colostrum management practices between male and female calves, and investigate the association between their discrepant colostrum practices and their attitudes toward male calf care.
For the marketing strategies, approximately half of small and medium farms sold calves between 3 and 7 d of age, in line with previous estimates from Canadian dairy producers (Renaud et al., 2018b;Wilson et al., 2020a).Furthermore, the marketing age of male calves was found to be associated with the herd size (number of lactating cows).That is, large farms (≥500 lactating cows) tended to market male calves before 3 d of age while small (<250 lactating cows) and medium The distribution of percentages of calves reported by survey respondents of male and female calves that received colostrum by 5 delivery methods (Q15 and Q20).The kernel density histogram shows the distribution shape of data with the wider section representing a higher probability of producers reporting a given percentage of calves and thinner sections corresponding to a lower probability.
(250 -499 lactating cows) farm marketed their calves between 3 and 7 d (Table 4).Small farms may only have calf transportation on a weekly or biweekly basis, whereas large farms with more frequent calvings often transported calves daily.The impact of early transpor- The distribution of percentages of male calves reported by survey respondents of male calves marketed by 6 methods (Q25).The kernel density histogram shows the distribution shape of data with the wider section representing a higher probability of producers reporting a given percentage of calves and thinner sections corresponding to a lower probability.
fore, certain countries have implemented regulations of minimum transport calf age to assure calf health and welfare (Wilson et al., 2020a).Furthermore, our results showed most producers marketed male calves through auctions and other farms and did not consider on-farm euthanasia as a reasonable mean to remove male calves even when the selling price was low.In contrast, previous studies reported some Canadian dairy producers might euthanize male calves at birth (an average of 19% male calves, Renaud et al., (2017)), and prefer selling male calves directly off the farm regardless of the buyers (Wilson et al., 2021).
Recent estimates showed a 13.1% (Scott et al., 2019) to 23.4% (England et al., 2023) of surplus dairy calves failed to receive passive immunity (FTPI), which can increase calves' risk of morbidity (Godden, 2008) and early mortality (Renaud et al., 2018a) in the veal and dairy-beef markets.In this study, male and female calves were fed with approximately 2.8 L of colostrum within 4 h after birth, which is comparable to previous Canadian studies (Renaud et al., 2018b;Wilson et al., 2022).A lower colostrum volume (2.83 L to females versus 2.80 L to males) and longer time until the first feeding (3.57h for females versus 3.70 h for males) were identified in male calves compared with females, however, these differences were smaller than those previously reported by Renaud et al. (2020) (0.21 L) and Shivley et al. (2019) (1.4 h).Nonetheless, similar to Renaud et al. (2020), the majority of surveyed producers provided consistent colostrum management practices to male and female calves, indicating male calves often received equal colostrum practices as females despite other on-farm challenges (e.g., pre-transportation sorting, early marketing, inadequate milk feeding) (Creutzinger et al., 2021).A large proportion of surveyed dairy producers valued opinions from their herd veterinarians over other stakeholders and the public in making calf management decisions.Herd veterinarians have been consistently considered as a source of trustworthy advice regarding calf management and animal welfare by Canadian dairy producers (Wolf et al., 2016;Sumner et al., 2018;Wilson et al., 2021;Russell et al., 2022).In contrast, opinions from other producers, stakeholders, and the public were perceived with varying degrees of importance (Russell et al., 2022;Wilson et al., 2022).Dairy producers' trust in herd veterinarians giving calf management advice was associated with the established faith for treating/advising lactating herds and providing relevant knowledge based on the familiarity with other farms (Sumner et al., 2020).Thus, our results verified that herd veterinarians played a critical role in calf management practices of dairy farms and might better implement interventions to improve on-farm calf management.
Most producers (57%, Figure 4) considered male dairy calves to be a valuable part of the dairy industry, higher than that reported by a previous study (47%) that implemented a similar questionnaire to Canadian producers (Wilson et al., 2022).In addition, producers reported a sense of responsibility for providing optimal care to on-farm male calves, considered male dairy calves to be a valuable part of the dairy industry, per- ceived male calves as an asset to the dairy industry, and believed their male calves were well taken care of.These results are in line with findings from Wilson et al. (2021Wilson et al. ( , 2022)), which reported that producers' willingness to provide optimal male calf care may be influenced by social norms, intrinsic pride, and ethical obligation.Additionally, approximately a third of producers recognized calf sale price as a motivation for optimal male calf care practices, suggesting financial incentives/profits can be an approach to improve on-farm care to male calves (Wilson et al., 2021;Creutzinger et al., 2022).Regarding to on-farm male calf care, our results showed most producers did not consider workload and financial costs as barriers to good male calf care (Figure 4).However, those who viewed workload as a barrier were marginally more likely to feed a lower volume of colostrum to male calves in the first feeding (Table 1).Because dairy farms profit primarily by selling milk, producers may place less value on male calves with less priority in care practices compared with females (Reed et al., 2022), and may implement suboptimal care practices for male dairy calves regarding colostrum and feeding management and disease prevention (Fecteau et al., 2002;Renaud et al., 2020;Creutzinger et al., 2022).The necessary time and effort needed to care for male calves have been identified as a barrier to optimal male calf care as producers may be unwilling or unable to provide care to male calves at the same level as females (Wilson et al., 2021;Reed et al., 2022).Likewise, the model identified that the organic farms (n = 46) were more likely to feed less colostrum to male calves in the first after-birth feeding.This effect of producing organic products on the colostrum management of male calves may relate to the fact that organic producers more frequently allowed calves to receive the first colostrum feeding by directly suckling from the dams (Pempek et al., 2017).Besides, as the questionnaires were mostly returned in physical mails by producers in Midwestern US (Table 1), responding organic dairy producers are more likely to be Amish and may have a variety of different management and attitudes about calf care (Brock and Barham, 2009).Although most dairy producers implemented identical colostrum practices to their male and female calves, these identified factors may affect how producers prioritize aspects and limited resources of calf care and implement different levels of care practices to male and female calves (Wilson et al., 2021).
There were several limitations to the current study.For example, the lack of associations in 2 multivariable regression models is in part due to the low frequency of discrepantly worse care practices for male calves (Table 3 and 4).Since the survey responses were self-reported, producers may incorrectly recall specific practices (re-call bias) or provide answers associated with a more positive perception (response bias).Besides colostrum feeding, male calves often undergo other challenges on the dairy farms, such as insufficient milk feeding and sorting for transportation (Creutzinger et al., 2021), which were not investigated herein.Furthermore, the indirect effect of discrepant colostrum practices and producers' attitudes on calf FTPI was not examined in the current study but should be considered for future studies.Likewise, although most producers did not receive feedback from calf buyers in this study, the potential effect of feedback on calf care practice changes and improvements is worth investigating.Since the questionnaire was delivered to 5 states east of Mississippi, these results are not generalizable to farms in western US regions or other countries.Some non-response bias is likely to be present.For instance, a higher proportion of US respondents reported producing organic milk (14.6%; 46/314) relative to the 2019 national census of the same 5 states (6.7%; 1,065/15,982) (USDA, 2019, 2020).A relatively high proportion of respondents also reported using atypical milking systems (e.g., 'Other' in Table 1) and reported having no regular veterinary visits.Since infrequent veterinary visits among organic producers has been previously noted (Brock et al., 2021), organic producers, who are commonly members of Plain or Amish communities, may be overrepresented in the data set.

CONCLUSION
The present study provides information on marketing strategies of male calves, differences in dairy producers' colostrum management between male and female dairy calves, and the association with producer attitudes toward male calf care.Male calves were often marketed through auctions between 3 and 7 d of age, however, large farms (≥500 lactating cows) more frequently sold their male calves before 3 d of age.Although male calves were found to experience a longer delay receiving the first colostrum feeding than females, most US dairy producers implemented similar colostrum feeding practices (source, delivery method, volume, timing) regardless of their demographics, farm characteristics, and attitudes toward male calf care.Most enrolled dairy producers perceived value in male calves and were willing to provide optimal care regardless of the workload and financial costs.Overall, the findings of this study indicate male dairy calves in this population were marketed at a younger age by large farms, but uncommonly received discrepantly worse on-farm colostrum management than females.Therefore, interventions to improve colostrum practices should be more broadly targeted toward all calves born on farms.
Cheng et al.: ATTITUDES ON MALE DAIRY CALF CARE Table Figure1.Proposed causal diagram for the relationships between measured herd and producer characteristics, producer's attitudes toward male calf care practices, and whether the male calves received poorer colostrum feeding practices than females.
Cheng et al.: ATTITUDES ON MALE DAIRY CALF CARE Cheng et al.: ATTITUDES ON MALE DAIRY CALF CARE Cheng et al.: ATTITUDES ON MALE DAIRY CALF CARE Table Figure2.The distribution of percentages of calves reported by survey respondents of male and female calves that received colostrum from 6 sources (Q14 and Q19).The kernel density histogram shows the distribution shape of data with the wider section representing a higher probability of producers reporting a given percentage of calves and thinner sections corresponding to a lower probability.
Figure3.The distribution of percentages of calves reported by survey respondents of male and female calves that received colostrum by 5 delivery methods (Q15 and Q20).The kernel density histogram shows the distribution shape of data with the wider section representing a higher probability of producers reporting a given percentage of calves and thinner sections corresponding to a lower probability.
Figure 4. Proportions of US dairy producers (n = 272) responding to the Likert-scaled questions regarding the level of agreement of 10 male calf care statements (Q23).*Percentages on the right end of the plot represent the total proportion of responses to "Strongly agree" and "Agree," while those on the left end indicate the sum of "Strongly disagree" and "Disagree." Figure 6.Proportions of US dairy producers (n = 272) responding to the Likert-scaled questions regarding the importance of opinions from 7 different stakeholders when making calf management decisions (Q30).*Percentages on the right end of the plot represent the total proportion of responses to "Very important" and "Important," while those on the left end indicate the sum of "Of little important" and "Not important." Cheng et al.: ATTITUDES ON MALE DAIRY CALF CARE Cheng et al.: ATTITUDES ON MALE DAIRY CALF CARE

Table 3 .
Male calf marketing strategy of responded dairy producers

Table 4 .
The distribution of participating dairy producers on the marketing age of male calves and the number of lactating cows