key: cord-1003463-7wx5v9b8
authors: Tautenhahn, A.; Merle, R.; Müller, K. E.
title: Factors associated with calf mortality and poor growth of dairy heifer calves in northeast Germany
date: 2020-09-24
journal: Prev Vet Med
DOI: 10.1016/j.prevetmed.2020.105154
sha: 26f050ebfabbf86cb93c0876b3fc7423859c651e
doc_id: 1003463
cord_uid: 7wx5v9b8

A cross-sectional study was conducted on fifty German dairy farms to identify risk factors for high mortality and poor growth in calves. Between 2012 and 2014, farm visits took place and a questionnaire on farm management practices was completed by in-person interview. In addition, heart girth measurements of calves around weaning were performed to estimate average daily weight gain. Furthermore, blood and faecel samples of calves were collected and a score addressing calf welfare was determined. The epidemiological associations between risk factors and high mortality and poor growth were estimated using two regression models. The factors significantly associated with high calf mortality (> 5%) were a high rate of calves with failure of passive transfer (> 25%) and the metaphylactic use of halofuginone lactate. A small amount of concentrates consumed around weaning, relocating calves more than twice until weaning and a low incidence risk of milk fever (< 5%) were found to be significantly associated with poor growth (median: 675 grams). Although the fifty farms cannot be considered as a representative sample for North-East Germany, the results indicate that the farm management has a big impact on growth and survival of dairy calves and needs to be addressed more thoroughly when raising the future dairy cow.

defence, by improvement of colostrum management and nutrition as well as minimizing stress by professional stockman ship in animal handling and by reducing the number of pathogens in the calf's environment (Lago et al., 2006; Windeyer et al., 2014; Al Mawly et al., 2015; Urie et al., 2018b) .

Previous studies reported average calf mortality rates between 3.3% and 5.3% for Norway, Canada, Switzerland, United States and the Netherlands (Gulliksen et al., 2009; Bleul, 2011; Windeyer et al., 2014; Urie et al., 2018a; Santman-Berends et al., 2019) . Few current data is available on calf mortality rates in Germany. Zitzmann et al. (2019) reported an average calf mortality rate of 7.7% for Thuringia in , Hoedemaker (2018 8.1%

for Lower Saxony in 2016 and Sanftleben (2009) 6,4% for Mecklenburg-Western Pomerania in 2007. No data is available on growth rates of preweaned dairy calves and calf rearing practices on German dairy farms.

Identifying risk factors for high dairy calf mortality and poor growth, will contribute to improve housing, feeding and management strategies on German dairies. Therefore, the objective of the present study was to identify factors associated with high mortality (> 5%) in dairy calves during the first six months of life and with poor growth in calves in the first three months of life.

The study was designed as an observational study and consisted of two models. In both models, the herd was the unit of concern. In the model "Risk factors associated with high calf mortality", a cross-sectional study was J o u r n a l P r e -p r o o f conducted with calf mortality, defined as mortality of calves between the second day and sixth month of life, as the dependent variable. At herd level calf mortality was not normally distributed and was therefore dichotomized in herds with high risk of calf mortality (> 5%) and herds with a low risk (≤ 5%). The classification of herds was based on the median calf mortality in the study population in 2012, which is in agreement with the target value for calf mortality of 5% proposed by Roy (1990) . In the model "Risk factors associated with median ADG from birth to weaning", average daily weight gain (ADG) of calves from birth until twelve weeks of life was the dependent variable at herd level.

Due to the limited study period and resources, we decided to enrol a total of 50 dairy herds in the study. For logistical reasons farms had to be located in northeastern Germany (Brandenburg, Saxony, Lower Saxony and Mecklenburg-Western Pomerania). Inclusion criteria for the study were an average herd size of ≥ 50 dairy cows and in-house rearing of calves and heifers. Most farms were enrolled in the projects "Brandenburger Testherden" of the cattle breeders' association Brandenburg (visited/contacted: n=20/58) and "Veredelungsland Sachsen 2020" of the state control association of Saxony (visited/contacted: n=10/10) and were invited to participate in the study by letter (Müller et al., 2016) . Additional farms belonged to the clientele of the Clinic for Ruminants and Swine of the Some of these farms have been working together with the clinic for several years; others contacted the clinic due to problems with calf rearing. We offered them to participate in the study as a first diagnostic step. During the study visits no other investigations than on the purpose of this study were made. In October 2013, members of the project "Brandenburger

Testherden" and of the Educational and Experimental Institution for Animal Husbandry Echem were asked for help with farm acquisition. Between

October 2013 and October 2014 the remaining 33 farms were visited.

Overall, 88 farms were invited to participate in the study. In detail, 68 farms were contacted by letter and 20 farms by phone with a response rate of 44%

and 100%, respectively. The overall response rate was 57%, which can be considered a high response rate. All farms entered the study voluntarily.

Each herd was visited on a single occasion by the same veterinarian (corresponding author) between September 2012 and October 2014. A questionnaire on farm management practices, morbidity and calf mortality was completed by in-person interview. In addition, blood und faecel samples were obtained to evaluate for failure of passive transfer (FPT), selected metabolic parameters (serum albumin, globulin) and enteropathogens often observed in calves with NCD. Heart girth measurements were conducted around weaning (12th week) to estimate ADG from birth to weaning.

Additionally, a score addressing calf welfare (Animal Needs Index by Winckler et al. (1994) ) was determined.

All variables were collected and retrieved on farm by a single investigator at a single farm-visit. This made a separate data collection of exposure and outcome variables impossible and therefore rules out blinding of the study.

This could lead to biased data what should be in mind when interpreting the results of this study.

The questionnaire was created hypothesis driven and corresponding to literature (Taffe et al., 2006; Schäffer et al., 2007; Bundesministerium, 2009; Lorenz et al., 2011a; Lorenz et al., 2011b) In this study we applied the centimetre scale. As described by Heinrichs et al. (1992) , heart girth measurements were carried out and the described formula was used to estimate life weight in kilograms for the breed German Holstein. One herd kept mainly the breed Jersey and was excluded from the model "Risk factors associated with median ADG from birth to weaning", because the calculation of ADG is not suitable for this breed.

Colostral antibody transfer was estimated on basis of serum total protein levels The test was carried out following the operating instructions.

For evaluation of husbandry conditions with respect to calf welfare a modified version of the Animal Needs Index 94 for calves (Tiergerechtheitsindex 94 für Kälber) described by Winckler et al. (1994) was applied. The Animal Needs Index (ANI) for calves covers seven areas of influence: movement behavior, feeding behavior, social behavior, resting behavior, comfort behavior, hygiene and supervision. In each area of influence, several parameters are graded using a score. A farm can achieve 

Calf mortality risk was calculated as follows: The average birth weight of 43 kg refers to Trilk and Münch (2008) , who determined the birth weights for the breed German Holsten in Northern Germany.

Data at individual calf level from blood and faecel testing as well as from heart girth measurements were transformed into data at herd level using the herd median or percentage of calves. The cut-off value for FPT and successful antibody transfer was set at < 55 g/l and ≥ 55 g/l, respectively, as recommended by Vandeputte et al. (2011) when the biuret-test for serum total protein examination is applied. At herd level, the percentage of calves with FPT was used for further analyses. Serum albumin levels in calves around the twelfth week of life was used to evaluate appropriate nutrition and health status before weaning. The authors assumed a threshold value of < 33 g/l serum albumin to be an indicator for malnourishment (and chronic disease) of preweaned calves. At herd level, the percentage of calves with low serum albumin was used for further analyses.

After execution of the ANI, the results were transferred into score values for each area of influence. At herd level results were expressed as percentage of the achieved score from maximum possible score value in each area of influence. For example: a farm with 13 points in the area of influence "supervision" (maximum possible score value: 20 points) achieved 65% of all possible points in this area of influence.

Due to possible information bias, we excluded the incidence risks of NCD, BRD and navel-ill as outcome variables. Diseases were treated at very different degrees of severity and most farmers estimated all incidence risks freely. Others counted the cases out of the treatment register (herd management program or stable book) and calculated incidence risks by dividing counted cases by the number born alive calves for NCD, BRD and navel-ill and by the number of calvings for milk fever and ketosis in the past J o u r n a l P r e -p r o o f twelve month before farm visit. Because of the importance of these variables for the outcome variables calf mortality and ADG we kept them in these models. Due to the convenience sampling strategy of farms selection bias cannot be ruled out. Confounding was controlled by including potential confounders in the multivariable regression models.

Before statistical analyses the data set was revised by using data cleaning techniques as removing duplicate data and correcting or marking obviously incorrect data. Missing or incorrect data was marked as missing values.

All statistical analyses were performed using the software SPSS (Version 20.0, SPSS Inc. 2012, USA). For the investigation of associations between potential risk factors with calf mortality and ADG from birth to weaning a multivariable model each was built.

At first, the large data set was reduced. Therefore, descriptive analyses of all data at herd level were performed. Continuous not normally distributed data was dichotomized or categorized. Potential risk factors were eliminated from further analyses if they were lacking variance (< 5% observations per category in binary outcomes), were missing biological causality or had too many missing values (> 20%, except for "Amount of concentrates consumed around weaning in kg" in the model for poor growth). Then all variables were tested for correlation using the Spearman's rank correlation coefficient. If the correlation coefficient was above 0.6, only the factor with the better biological plausibility was selected for further analyses. The remaining potential risk factors as well as categories and observed J o u r n a l P r e -p r o o f frequencies are summarized in Table 1 . Table 1 is displayed in the Supplements of this article.

The associations of calf mortality (binary: ≤ 5%, > 5%) with potential risk factors (n = 52) were tested in univariable analyses. Candidate variables with binary outcome were tested using chi-square-test and those with categorical or continuous outcome using logistic regression. Factors with a p-value ≤ 0.2 (n = 16) qualified for multivariable analysis. Due to a limited number of herds (n = 50) in the study the number of candidate variables was reduced according to the p-value to a maximum of seven candidate variables. In the first step, the multivariable logistic regression model was reduced by using a manual stepwise backward procedure, with p < 0.1 as criterion for retention. In the second step, excluded variables were reentered one by one. The final model only included variables that were significant at a significance level of p < 0.05. Confounding and interaction effects were considered in the model. In the end, no confounders were discovered in the model and none of the two-way interactions were significant in the model and therefore, all interaction terms were removed. variables with binary outcome were tested using Student's t-test, those with categorical outcome using analysis of variance (ANOVA) and with continuous outcome using linear regression. Factors with a p-value ≤ 0.2 (n = 25) qualified for multivariable analysis. As described in the previously model a maximum of seven candidate variables were included in a multivariable linear regression model. The potential risk factor "amount of concentrates consumed around weaning" was used in the model with an adjusting factor to weight the observations, to account for heteroscedasticity of the data (weighting was done using "weighted least squares"). Further analysis was performed as described above. In the model "Risk factors associated with median ADG from birth to weaning", the fit of the model was evaluated with the adjusted R-squared and by assessing the residuals.

Plots of the standardized residuals against the predicted values were observed for their pattern and distribution and for outliers.

Herd size ranged from 70 to 1414 cows (median: 419 cows) with a median milk yield of 9800 kg per cow and year (range: 7680 -12000 kg). Median calf mortality risk in 2012 was 5.0% (range: 0.0% -17.7%). Herd characteristics of low and high mortality herds are presented in Table 2 .

Median herd level incidence risk for NCD, BRD and navel-ill in calves (treatment) was 12.0% (range: 0.0% -90.0%, Q 25%: 5.0%; Q 75%: 27.0%),

17.5% (range: 0.1% -90.0%, Q 25%: 9.4%; Q 75%: 30.0%) and 1.6%

(range: 0.0% -30.0%, Q 25%: 1.0%; Q 75%: 4.2%), respectively. Median herd level incidence risk for milk fever and ketosis treatment of dairy cows J o u r n a l P r e -p r o o f was 4.6% (range: 1.0% -35.0%, Q 25%: 3.0%; Q 75%: 6.7%) and 3.1%

(range: 0.5% -46.0%, Q 25%: 1.5%; Q 75%: 6.6%), respectively. with FPT compared to farms visited in winter (p = 0,077).

Serum albumin, total protein and globulin levels were determined in 518 calves around weaning with a herd median of 34.7 g/l (range: 29.5 g/l -37.4 g/l), 60.9 g/l (range: 52.0 g/l -72.1 g/l) and 25.5 g/l (range: 18.7 g/l -37.6 g/l), respectively. 40.0% of the herds had at least 25% calves per herd with a serum albumin concentration < 33.0 g/l. The authors assume a threshold value of ≥ 33 g/l serum albumin to be an indicator for malnourishment of preweaned calves. respectively. Relevant descriptive data of the questionnaire and the ANI is presented in a summarized form in Table 1 .

Results from univariable analyses are presented in Table 3 . Seven of these variables were introduced to the model "Risk factors associated with high 

Results from univariable analyses are presented in Table 5 . Seven of these variables were introduced into the model "Risk factors associated with median ADG from birth to weaning" selected by the lowest p-value in univariable analyses. After manual backward selection, the variables "Amount of concentrates consumed around weaning" (p < 0.001),

"Frequency of relocation of calves between birth and weaning" (p < 0.001) and "Incidence risk of milk fever" (p = 0.001) remained in the final multivariable linear regression model (Table 6 ) and explained 72.8% of the variance between herds (adjusted R-squared). The amount of consumed concentrates around weaning was associated with ADG until weaning.

Median ADG increased by 160 grams (95% confidence interval 107 -213) at herd level. Frequent relocation of calves turned out to be a risk factor for poor growth until weaning. Calves that were relocated on the same farm more than twice from birth until weaning gained 119 grams per day less until weaning than calves that were relocated not more than twice (95% confidence interval -172 --67). Farms with a high incidence risk of milk fever treatment in periparturient cows (> 5%) had 115 grams more ADG until weaning than farms with a lower incidence risk (95% confidence interval 55 -175). 

FPT of more than 25% of the neonatal calves in a herd was associated with high calf mortality. This finding is in accordance with results of previous studies demonstrating that total serum protein levels below 55 g/l in J o u r n a l P r e -p r o o f neonatal calves are a risk factor for lethal outcome (Rea et al., 1996; Tyler et al., 1998; Torsein et al., 2011) .

In the present study, Cryptosporidium parvum was detected in faecel samples obtained from calves on 49 (98%) farms with a median percentage of 72.7% of calves between 5 and 28 days of age. Halofuginone lactate was administered to all neonatal calves on nearly half (46%) of the farms visited.

Farms on which routine administration of halofuginone lactate was performed had 10.0 times higher odds for calf mortality risk above 5%.

Similar observations were made by Fourichon et al. (1997) , who observed a higher mortality in neonatal calves on farms applying medical prevention

for digestive disorders. One explanation could be that farms with high risk of calf mortality due to NCD use halofuginone lactate more often than farms with less problems with NCD. In contrast to these observations, other researchers demonstrated the beneficial effect of metaphylactic halofuginone treatment (Keidel and Daugschies, 2013) . A toxic effect of halofuginone lactate as reason for increased calf mortality is unlikely as Villacorta et al. (1991) observed toxic side effects at much higher dosages (500 µg/kg BW) than those recommended by producers (5-10 µg/kg).

Risk factors that did not remain in the multivariable model for high calf mortality, but showed a significant (p < 0.05) association with calf mortality, are discussed in this section.

The risk factor "age at first offer of hay" did not remain in the model although no offer of hay in the first days of life compared to early supply was associated with higher calf mortality in the univariable analysis (p = 0.033).

J o u r n a l P r e -p r o o f Torsein et al. (2011) and Perez et al. (1990) observed lower calf mortality rates on farms that offered roughage to calves from the first week of life onwards compared to those farms that offered roughage shortly before weaning. Perez et al. (1990) assumed that the supply of roughage to neonatal calves enhances early rumen development. In practice, feeding concentrates to young calves is preferred to offering hay as concentrates were proven to enhance rumen development more efficiently than hay (Noci, 2010 ). In addition, hay feeding was shown to reduce the amount of concentrates consumed (Žitnan et al., 1998) . Early supply of high amounts of concentrates without any roughage was shown to cause hyperkeratosis and clumping of rumen papillae. To this end, the hay provided is thought to prevent hyperkeratosis of rumen papillae by evoking a scratching effect on the rumen epithelium (Suárez et al., 2007; Noci, 2010) .

Promoting solid feed intake of calves during the pre-weaning period has a positive effect on rumen development and facilitates the transition from milk to solid feed at weaning (Khan et al., 2011b) . The intake of high amounts of concentrates in the pre-weaning period was associated with high ADG until weaning (+ 130 ADG per kg concentrates). This is in line with the results of Relocating calves more than twice from birth until weaning was related to lower ADG. Corresponding observations were made by Mormède et al. (1990) and Siegel and Latimer (1975) in rats and chickens. As a result of repeated regrouping and relocation, animals showed signs of chronic stress such as aggression against herd mates and insufficient ADG. Veissier et al.

(2001) did not observe adverse effects on ADG due to regrouping and relocating of calves but measured an increased stress response compared to controls. They suspected a negative effect of regrouping and relocation on ADG and calf health under field conditions when more than two calves form a group. More research is needed to confirm their assumptions.

The association between incidence risk of milk fever in dairy cows and ADG in calves was an unexpected result. Calves showed higher ADG on farms with a higher milk fever incidence risk. This result is in contrast to former publications that describe significant health implications for both dams and calves on farms with a high milk fever incidence risk, among these, dystocia and the weak calf syndrome (Gröhn et al., 1989; Houe et al., 2001; Wilhelm et al., 2017) . Weak calves consume less first colostrum, fall ill more often and have reduced ADG (Besser et al., 1990; Wittum and Perino, 1995; Weaver et al., 2000) . One explanation for our findings could be a higher percentage of cows with ≥ 3 parities on farms with higher incidence risk of milk fever treatment. Milk fever is usually a disease of dairy cows in their third lactation or beyond (Correa et al., 1993) . At the same time multipara J o u r n a l P r e -p r o o f have richer first colostrum (Tyler et al., 1999; Scholz et al., 2011) and therefore their offspring has a decreased risk of FPT, sickness and reduced ADG (Robison et al., 1988; Wittum and Perino, 1995; Windeyer et al., 2014) .

Risk factors that did not remain in the multivariable model for median ADG, but showed a significant (p < 0.05) association with ADG, are discussed in this section.

As expected the risk factors "time per day without staff at the farm" (p = 0.024) and "maximal time interval between calving and harvesting first colostrum of the dam" (p = 0.019) were associated with ADG. A precondition for early first colostrum harvesting is that staff members are present to take over the latter task. In our study, collecting first colostrum within two hours after calving at maximum versus a more extended period was associated with better growth in neonatal calves. Several studies proved before, that a delay in first colostrum harvesting leads to reduced immunoglobulin G concentrations due to the diluting effect of milk synthesis in the freshly calved cow (Moore et al., 2005; Morin et al., 2010; Scholz et al., 2011) .

Calves that consume first colostrum with low concentrations of immunoglobulin G have a higher risk of FPT (Besser et al., 1991) and thus are at risk for diseases and poor growth (Robison et al., 1988; Wittum and Perino, 1995; Windeyer et al., 2014) .

Feeding at least three litres of first colostrum at first meal was associated with higher weight gains before weaning (p = 0.031). This finding is in accordance with observations by others (Faber et al., 2005 ; Trotz-Williams J o u r n a l P r e -p r o o f Beam et al., 2009) . Early and sufficient colostrum supply is one of the main protective factors against FPT, which is connected to poor growth, as described above.

Farms that started offering concentrates to calves beyond two weeks of life had lower ADG from birth to weaning than farms that fed concentrates earlier (p = 0.015). Most of the study farms reared their calves with a restricted milk feeding routine und tried to wean calves as early as possible to reduce feeding costs. In particular, calves fed restricted depend on early rumen development for sufficient growth. Therefore, concentrates that are supposed to be the most effective feed for early rumen development need

to be offered to calves as early as possible (Tamate et al., 1962; Forbes, 1971; Noci, 2010) .

Farms that abandoned hay from the diet of preweaned calves had higher ADG in this study than farms that fed hay unchopped and separately (p = 0.025). This result is in line with studies (Warner et al., 1956; Jahn et al., 1970; Kertz et al., 1979) in which calves were exposed to a restricted milk feeding routine. Pre-ruminant calves consumed less concentrates when they were fed hay separately. The authors concluded that limited rumen capacity in young calves determines the amount of solid feed intake. To this end, the simultaneous offer of hay and concentrates would reduce ADG due to the lower energy density of hay compared to concentrates. In further studies, pre-ruminant calves were fed chopped hay either separately, or mixed with concentrates (Coverdale et al., 2004; Suárez et al., 2007; Khan et al., 2011a) . None of these authors could show a negative effect of hay on ADG. Taking the protective effect of hay on calf mortality into account hay feeding to calves seems to be recommendable.

Evaluating the data from the Animal Needs Index, we observed higher ADG on those farms that fulfilled the requirements of calves more efficiently than farms with insufficient ADG. Farms with more than 65% of points in the area of influence "supervision" in the Animal Needs Index had higher ADG than farms with less points (p = 0.002). Differences between farms relied mainly on differences in documentation of symptoms and treatment of diseases.

This corresponds to the results of Lundborg et al. (2005) . They found a positive correlation between proper documentation and good calf health and draw the conclusion that thoroughness in documentation reflects a good quality of calf raising management.

In our study, we found a strong positive correlation of median serum albumin concentrations and ADG until weaning (p < 0.001). At herd level, each onegram increase in serum albumin concentration was associated with a rise in ADG by 46 grams. Low serum albumin levels are a constant finding in malnourished and underweight children (Clarke et al., 2006; Cripps et al., 2008) . In piglets and calves, the predictive capacity of serum or plasma albumin concentrations has been examined in the context of different rearing intensities (restricted vs. ad libitum feeding) in the first month of life (Hammon et al., 2002; Liu et al., 2015; Maccari et al., 2015) . A positive association between body weight and plasma albumin concentration was detected in mature humans by Jeejeebhoy et al. (2015) . Although in individual animals low serum albumin concentrations can be the J o u r n a l P r e -p r o o f consequence of either malnutrition or a variety of disorders (protein loosing enteropathy, liver degeneration), on herd level, we consider low serum albumin (< 33 g/l) as predicting indicator for malnourishment or for an elevated proportion of calves with chronic diseases leading to insufficient ADG from birth to weaning. Its suitability as indicator, however, has to be investigated in subsequent studies.

Our statistical analyses included dealing with data challenges such as multicollinearity, finding associations 'due to chance alone', confounding and interaction effects (Dohoo et al., 1997) . We used techniques to reduce the number of independent variables and to select for variables with the highest explanatory power before inserting them into multivariable models.

Furthermore, confounding and interaction effects were considered for in the models. Due to the limited number of farms in this study, the number of independent variables per final multivariable regression model had to be reduced to a maximum of seven variables to reduce the possibility to find associations just due to chance alone. Since more than seven risk factors may effect multifactorial diseases in calves, we had to select the variables carefully.

The results of the present field study indicate that high calf mortality (> 5%), FPT in the neonate (serum protein < 55 g/l) and low ADG from birth to weaning (< 700 g/day) are still a problem on dairy farms under livestock production conditions in northeast Germany. As the welfare of food producing animals and in particular of young stock comes more and more J o u r n a l P r e -p r o o f into the focus of society, the management of calf rearing should be systematically evaluated and improved in the light of recent insights into nutrition, husbandry conditions, animal handling and disease prevention.

Especially colostrum and feeding management routines on most farms need to be revised and checked more frequently. Feeding routines should focus on high rates of ADG until weaning. Offering water and concentrates right from the start enables calves to consume sufficient amounts of concentrates at weaning and leaves them prepared for the milk deprivation at weaning.

Animal handling and husbandry conditions should be reviewed from an animal perspective to reduce unnecessary stressful routines as frequent relocating of calves until weaning.

connected with the funding associations, helped with the farm acquisition and supervised the corresponding author in this study. The author Roswitha

Merle supported the study with the development of the assessment strategy and by performing data analysis.

All examinations and sample collections were performed in line with legal regulations on the performance of experiments on animals (Bundesministerium, 2010) .

In conduct with this research quality standards like standard operating procedures for peripheral venous blood sampling and faecel sampling of the Clinic for Ruminants and Swine of the Freie Universität Berlin and ‚Safeguarding Good Scientific Practice' of the German Research Foundation (DFG) were taken into account. J o u r n a l P r e -p r o o f 

Risk factors for neonatal calf diarrhoea and enteropathogen shedding in New Zealand dairy farms

Tiergerechtheit bewerten. Kuratorium für Technik und Bauwesen in der Landwirtschaft e

Meta-analysis of the effect of initial serum protein concentration and empirical prediction model for growth of neonatal Holstein calves through 8 weeks of age

Comparison of three methods of feeding colostrum to dairy calves

Decreased colostral immunoglobulin absorption in calves with postnatal respiratory acidosis

Risk factors and rates of perinatal and postnatal mortality in cattle in Switzerland

Investigation about quantitative benchmarking of animal health. Dissertation

An examination of the influence of marketing organisations on animal health and meat quality of fattening pigs on the basis of collected slaughter check results, pH-values and meat temperature of the ham

Verordnung zum Schutz landwirtschaftlicher Nutztiere und anderer zur Erzeugung tierischer Produkte gehaltener Tiere bei ihrer Haltung: TierSchNutzV. In: Bundesgesetzblatt

Tierschutzgesetz: TierSchG

The influence of various degrees of confinement and supervision on the incidence of dystokia and stillbirths in Hereford heifers

New Common Animal Health Strategy

Case study: effects of colostrum ingestion on lactational performance 1

Effects of increased dietary protein and energy on composition and functional capacities of blood mononuclear cells from vaccinated, neonatal calves

Physiological changes affecting voluntary food intake in ruminants

Critical points related to housing and management in control programmes for calf morbidity and mortality in French dairy herds. 9 th International Congress in Animal Hygiene

Fuel feeds function: energy metabolism and the T-cell response

Management risk factors associated with calf diarrhea in Michigan dairy herds

Potential risk factors for Cryptosporidium infection in dairy calves

Epidemiology of metabolic disorders in dairy cattle: Association among host characteristics, disease, and production

Calf mortality in Norwegian dairy herds

Feed intake patterns, growth performance, and metabolic and endocrine traits in calves fed unlimited amounts of colostrum and milk by automate, starting in the neonatal period

Predicting body weight and wither height in Holstein heifers using body measurements

Verminderung von Aufzuchtverlusten in niedersächsischen Milchviehbetrieben

Milk fever and subclinical hypocalcaemia--an evaluation of parameters on incidence risk, diagnosis, risk factors and biological effects as input for a decision support system for disease control

Nutritional assessment: comparison of clinical assessment and objective variables for the prediction of length of hospital stay and readmission

Integration of halofuginone lactate treatment and disinfection with p-chloro-m-cresol to control natural cryptosporidiosis in calves

An early weaning calf program: summarization and review

Hay intake improves performance and rumen development of calves fed higher quantities of milk

Invited review: Effects of milk ration on solid feed intake, weaning, and performance in dairy heifers

Farm characteristics and calf management practices on dairy farms with and without diarrhea: A case-control study to investigate risk factors for calf diarrhea

Calf respiratory disease and pen microenvironments in naturally ventilated calf barns in winter

Effects of dietary protein/energy ratio on growth performance, carcass trait, meat quality, and plasma metabolites in pigs of different genotypes

Calf health from birth to weaning. III. housing and management of calf pneumonia

Calf health from birth to weaning. I. General aspects of disease prevention

Effects of two different rearing protocols for Holstein bull calves in the first 3 weeks of life on health status, metabolism and subsequent performance

Multikausale Infektionskrankheiten

Effect of delayed colostrum collection on colostral IgG concentrationin dairy cows

Effect of colostral volume, interval between calving and first milking, and photoperiod on colostral IgG concentrations in dairy cows

Multiple neuroendocrine responses to chronic social stress: Interaction between individual characteristics and situational factors

Bewertung von Hygiene

Effects of different rations on growth and rumen development of calves. Dissertation

Effects of chronic environmental cold on growth, health, and select metabolic and immunologic responses of preruminant calves

Composition and functional capacity of blood mononuclear leukocyte populations from neonatal calves on standard and intensified milk replacer diets

Management Factors Related to Calf Morbidity and Mortality-Rates

The effects of disease, management, and nutrition on average daily gain of dairy heifers from birth to four months

Herd health and production management in dairy practice

Prediction of calf mortality by use of tests for passive transfer of colostral immunoglobulin

Relationship of various incoming cattle traits with feedlot performance and carcass traits

Effects of Passive-Immunity on Growth and Survival in the Dairy Heifer

Invited review: Influence of climatic conditions on the development, performance, and health of calves

Influence of weaning method on health status and rumen development in dairy calves

The calf: Volume 1 Management of health

Vorbeuge von Kälberkrankheiten durch richtige Aufzucht und Fütterung in der Milchviehhaltung. 27. Fachtagung LKV/RGD

Quantifying calf mortality on dairy farms: Challenges and solutions

Critical control points (CCP) for the housing and management of calves

Factors of influence on the quality of colostrum from dairy cows

Preweaned heifer management on US dairy operations: Part VI. Factors associated with average daily gain in preweaned dairy heifer calves

Social interactions and antibody titres in young male chickens (Gallus domesticus)

The effect of respiratory disease and a preventative antibiotic treatment on growth, survival, age at first calving, and milk production of dairy heifers

Effect of roughage source and roughage to concentrate ratio on animal performance and rumen development in veal calves

Morbidity in Swedish dairy calves from birth to 90 days of age and individual calf-level risk factors for infectious diseases

Kälbersterblichkeit senken, Aufzuchtverluste minimieren

Effect of various dietaries on the anatomical development of the stomach in the calf

Risk factors for calf mortality in large Swedish dairy herds

Connections between health of calves, growth and later yields of dairy cattle

Use of serum protein concentration to predict mortality in mixedsource dairy replacement heifers

Colostral immunoglobulin concentrations in Holstein and Guernsey cows

Preweaned heifer management on US dairy operations: Part I. Descriptive characteristics of preweaned heifer raising practices

Preweaned heifer management on US dairy operations: Part V. Factors associated with morbidity and mortality in preweaned dairy heifer calves

Comparison of four refractometers for the investigation of the passive transfer in beef calves

Calves' responses to repeated social regrouping and relocation

Efficacy of halofuginone lactate against Cryptosporidium parvum in calves

Ruminant nutrition, dietary factors influencing development of ruminant stomach

Passive transfer of colostral immunoglobulins in calves

Effect of serum calcium status at calving on survival, health, and performance of postpartum Holstein cows and calves under certified organic management

Tiergerechtheitsindex für Kälber

Factors associated with morbidity, mortality, and growth of dairy heifer calves up to 3 months of age

Antimicrobial resistance global report on surveillance: 2014 summary. World Health Organization

Influence of dietary concentrate to forage ratio on the development of rumen mucosa in calves

Risk factors for calf mortality influence the occurrence of antibodies against the pathogens of enzootic bronchopneumonia

The study was supported by the cattle breeders' association Brandenburg "Brandenburger Testherden", the managers of the project "Veredelungsland Sachsen 2020" of the state control association of Saxony and the Educational and Experimental Institution for Animal Husbandry Echem by helping with the farm acquisition. The authors thank the participating farmers for their interest and support.

Declarations of interest: none.