Factors associated with neonatal dairy calf mortality in a hot-arid environment

Calf mortality in Turkish dairy farms: Economic impact, regional disparities, and farm-level drivers

This study investigates the economic burden of calf mortality in Turkish dairy farms and its impact on the national economy. We gathered research data by directly surveying dairy farms in seven provinces, each representing a distinct region of Turkiye. By conducting these surveys, we captured data on various aspects of calf mortality, including losses among non-pregnant cows aged two and older, pregnant cows, and those experiencing complications during birth, as well as losses within the 0-6 month age bracket. These figures were then amalgamated to establish the overall calf loss rate. Using a fractional probit model, we examined the empirical relationship between total calf loss rates and the socio-demographic characteristics of farm operators and their establishments. Our findings revealed that approximately 82 % of farms experienced some degree of calf loss, with the calf loss rate among dairy cattle farming accounting for nearly 20 %. Notably, regional disparities emerged as a key observation, alongside the identification of certain socio-demographic farm characteristics that proved statistically significant. Specifically, factors such as the prevalence of local cattle breeds, the proportion of crossbred bulls, as well as the numbers of heifers and calves, stood out as influential. Further scrutiny, fortified by ANOVA tests and relationships between the number of cows and total calf loss rate, underscored pronounced geographical disparities in post-estimation calf loss rates. Meanwhile, correlation heatmaps illuminated noteworthy relationships between specific cattle traits and the extent of calf losses. These findings not only underscore the severity of the issue but also highlight the urgency of preventive measures. In light of these insights, we offer pertinent policy recommendations to stakeholders and policymakers aimed at mitigating this considerable economic burden effectively.

Calf care workers' attitudes and personality and their association with calf mortality in large-scale dairy farms

Although calf mortality is a multifactorial problem, little is known about the attitudes and personalities of calf care workers (CCWs) and their association with calf mortality. This study aimed to describe the attitudes, satisfaction, and personality of CCWs in large Estonian dairy herds and to analyze their associations with herd calf mortality. A questionnaire registering CCWs' attitudes toward their work and calf mortality, personality characteristics, satisfaction and importance of different job-related factors was developed. In total, completed questionnaire data of 161 CCWs from 108 large (>100 cows) Estonian dairy farms were analyzed. Herd-level yearly calf mortality risk (MR) was calculated. Cluster analysis and variance partitioning analysis were applied to reveal the explanatory capacity of CCWs' attitudes and personalities on calf mortality. The mean yearly herd-level calf MR was 5.4% during the first 21 days of life and 2.7% during 22-90 days of life. Although good calf health and low calf mortality was important for CCWs, dead calves were often seen as inevitable. CCWs were generally doubtful regarding their capacity and available knowledge to influence calf mortality. In high-mortality herds, CCWs were dissatisfied with the calf health situation and farm working equipment and felt that the situation was out of their control. Despite striving, they had less faith that farmworkers could affect the outcomes, such as calf mortality. CCWs' personality domains explained <5% of the variance in the herd's calf MR, whereas their attitudes and satisfaction explained 20% of the variability in calf MR. The current study revealed the importance of the attitudes and satisfaction of CCWs on calf mortality and highlighted the need to allocate proficient assistance to herds with high calf mortality to mitigate calf health problems and the resulting consequences for CCWs.

Incidence and Predictors of Calf Morbidity and Mortality From Birth to 6-Months of Age in Dairy Farms of Northwestern Ethiopia

The Ethiopian government has initiatives for expanding the commercial and smallholder market-oriented urban and peri-urban dairy production systems to meet the demands for dairy products. However, there have been only limited on-farm studies on the health performance of commercial dairy breeds. The aim of this longitudinal study was to quantify the incidence and identify predictors of calf morbidity and mortality from birth to 6 months of age in urban and peri-urban dairy farms of Northwest Ethiopia. A total of 439 calves aged below 6 months from 174 dairy farms were included in the study. We collected data on 35 potential risk factors to determine their effect on calf morbidity and mortality in the area. Kaplan-Meier survival analysis was used to summarize survival probability. The Cox proportional hazard regression model with shared frailty to account for unmeasured herd-specific heterogeneity was also used to identify and quantify factors associated with time to morbidity and mortality. Among 439 calves enrolled for 6 months of follow-up period, a total of 141 morbidities and 54 mortality events were recorded. This gives an overall morbidity and mortality incidence rates of 64 per 100-calf 6-months at risk (risk rate of 47.3%) and 19 per 100-calf 6-months at risk (risk rate of 17.9%), respectively. Diarrhea was the most frequent calf health problem with a risk rate of 25.2%. It was the cause of death for 33.3% of all the 54 calf deaths. Next to diarrhea, pneumonia ranked second with risk rate of 8.6% and was responsible for death of 12.9% of all the 54 calf deaths. Among 35 potential risk factors, calf age, vigor status at birth, calf breed, colostrum ingestion, and herd size were significant (p < 0.05) predictors of calf morbidity and mortality. The Cox-shared frailty model revealed that the herd frailty component had no significant effect on hazard estimates of the covariates of all-cause morbidity and mortality. This implies that the dairy herds participated in the study were homogeneous in the distribution of unmeasured random effects. In conclusion, the magnitude of calf morbidity and mortality was higher and above economically tolerable level in this study. This could impede the success of Ethiopia's dairy development initiative in general, and the livelihood of smallholder dairy producers in particular. Therefore, educating farmers aimed at mitigating the identified risk factors can reduce calf morbidity and mortality in the study areas.

Refining livestock mortality indicators: a systematic review

Background: Livestock mortality impacts farmer livelihoods and household nutrition. Capturing trends in livestock mortality at localised or national levels is essential to planning, monitoring and evaluating interventions and programs aimed at decreasing mortality rates. However, livestock mortality data is disparate, and indicators used have not been standardised. This review aims to assess livestock mortality indicator definitions reported in literature, and define the ages where mortality has greatest impact. Methods: A systematic review was conducted, limited to articles focussed on mortality of cattle, sheep and goats. Peer-reviewed articles in Web of Science until year 2020 were assessed for inclusion of age-based definitions for mortality indicators and data on age distribution of mortality. Indicator definitions for each species were collated and similar terms and age groups most targeted were compared. The cumulative distribution of age at mortality was compared across studies graphically where possible; otherwise, age patterns for mortality were collated. Results: Most studies reported mortality risk rather than rate, and there was little agreement between indicator definitions used in the literature. The most common indicators reported were perinatal and neonatal mortality in cattle, and for perinatal, neonatal and pre-weaning mortality indicators for sheep and goats. Direct comparison of age distribution of mortality was only possible for cattle, which found that approximately 80% of all mortalities within the first 12 months had occurred by six months of age. A significant finding of the study is the variation in age groups for which mortality is reported, which impedes the comparison of mortality risk across studies, particularly for sheep and goats. Conclusions: This study demonstrates the importance and value of standardising mortality risk indicators for general use, including a young stock mortality risk indicator measuring mortality in the highest risk period of birth to six months of age in cattle, sheep and goats.

The Effect of Metaphylactic Use of Tildipirosin for the Control of Respiratory Disease in Long-Distance Transported Dairy Calves

The objective of this study was to evaluate the efficacy of two metaphylactic strategies using tildipirosin for the control of bovine respiratory disease (BRD) in dairy calves transported to a heifer raising facility within their first week of life. A total of 2,100 calves were enrolled in the study. Animals were transported for ~1,715 km, from dairies located in Minnesota to a calf raising facility located in New Mexico, where they were housed in individual hutches until weaning. Three days after arrival, calves were randomly allocated into three groups: (1) META1: single subcutaneous (SQ) injection of tildipirosin (Zuprevo™, Merck Animal Health) at enrollment at 4 mg/kg; (2) META2: SQ injection of tildipirosin at enrollment and 17 days later; (3) CON: untreated controls. The BRD incidence was 11.4, 10.8, and 9.4% for calves enrolled in the CON, META1, and META2, respectively (P = 0.44). Lung lesions diagnosed through ultrasonography was found in 21.0, 21.0, and 21.8% of calves enrolled in CON, META1, and META2, respectively (P = 0.99). Mortality tended to be greater for CON calves in comparison to META2 calves (1.5 vs. 0.6%, P = 0.06), but did not differ between calves enrolled in CON and META1 groups (1.5 vs. 1.2%, P = 0.55). Growth was not affected by metaphylaxis. The average daily gain for calves enrolled in CON, META1, and META2 was 517, 518 and 525 g, respectively (P = 0.25). Blood analysis revealed that some of the markers of inflammation assessed were influenced by metaphylaxis. At 27 days after enrollment, META2 calves had decreased concentrations of haptoglobin, serum amyloid A, and aspartate aminotransferase, compared to CON calves (P < 0.05). Additionally, CON calves had increased concentrations of globulins and lower albumin to globulin ratio than META2 calves at the end of the weaning period (P < 0.05). In conclusion, tildipirosin metaphylaxis did not decrease the incidence of BRD nor did it have an impact on weight gain. However, metaphylaxis with two injections of tildipirosin at enrollment and 17 days later tended to reduce mortality and improved the systemic inflammatory status of calves during the preweaning period.

Heat stress in dairy calves from birth to weaning

This Research Reflection collects current knowledge on the effects of heat stress in dairy calves. Chapters cover the concept of foetal programming, animal-based and environmental indicators of heat stress in the postnatal period, and methods of heat stress abatement. Conclusions for further research about economic efficiency, research methodology and an integrated approach of pre- and postnatal heat stress are also proposed.

Immunofluorescence and molecular diagnosis of bovine respiratory syncytial virus and bovine parainfluenza virus in the naturally infected young cattle and buffaloes from India

Pneumonia in bovines is a multifactorial disease manifestation leading to heavy economic losses. Infections of bovine respiratory syncytial virus (BRSV) and bovine parainfluenza virus-3 (BPI-3) are among the important contributing factors for the development of pneumonia in young animals. These viral agents either primarily cause pneumonia or predispose animals to the development of pneumonia. Although, the role of BRSV and BPI-3 in the pathogenesis of pneumonia is well established, there are no reports of involvement of BRSV and BPI-3 from Indian cattle and buffaloes suffering from pneumonia. In the present investigation, we performed postmortem examinations of 406 cattle and buffaloes, which were below twelve months of age. Out of 406 cases, twelve (2.95%) cases were positive for BRSV and fifteen (3.69%) cases were positive for BPI-3, screened by reverse transcriptase polymerase chain reaction (RT-PCR). Further, positive cases were confirmed by sequence analysis of RT-PCR amplicons and direct immunofluorescence antibody test (d-FAT) in paraffin-embedded lung tissue sections. BRSV positive cases revealed characteristic findings of bronchiolar epithelial necrosis, thickened alveolar septa by mononuclear cells infiltration and edema; alveolar lumens were filled with mononuclear cells and numerous syncytial cells were seen having intracytoplasmic inclusions. The BRSV antigen distribution was found to be in bronchiolar and alveolar epithelium and syncytial cells in the lung sections. In fifteen cases, where BPI-3 was detected, bronchointerstitial pneumonia in the majority of cases with thickened alveolar septa by mild macrophage infiltration, hyperplasia of type-II pneumocytes and bronchiolar necrosis along with syncytial cells having intracytoplasmic inclusions in the majority of cases were observed. The BPI-3 antigen distribution was found to be in bronchiolar and alveolar epithelium and syncytial cells in the lung sections. RT-PCR amplicons of BRSV and BPI-3 obtained were sequenced and their analysis showed homology with already available sequences in the NCBI database. It is the first report of detection of BRSV and BPI-3 from pneumonic cases by RT-PCR and d-FAT from cattle and buffaloes of India, indicating the need for more epidemiological studies.

•

BRSV and BPI-3 induce primary pneumonia.

•

Syncytia with cytoplasmic inclusion was seen.

•

RT-PCR and dFAT are confirmatory diagnosis.

Incidence of Calf Morbidity and Its Predictors in North Shewa, Amhara, Ethiopia

Calf morbidity is an important productivity factor that results in huge economic losses in the success of livestock production in Ethiopia. However, there is no robust information on its rate and its predictors in the mixed crop livestock production system as most studies are targeted to intensive dairy farms. A longitudinal study design was conducted from December 2018 to April 2019 in Siyadeber and Wayu districts of Amhara region, Ethiopia. A total of 135 apparently healthy calves were enrolled from randomly selected fifty-fifty households in three Kebeles of the district, namely, Gash-amba, Siyadeber, and Wale-deneba. A pretested structured questionnaire was used to collect data about the potential risk factors upon the face-to-face interview made with the owners. Calves were monitored for the incidence of morbidity in a weekly visit basis, and any clinical abnormalities were recorded on registries. The chi-square and Fisher’s exact test followed by Generalized Linear Models for binomial family extensions for risk estimate were run, and a p value <0.05 was considered statistically significant. In this study, the overall incidence rate of calf morbidity among under six months of age was 388 calves per 100,000 days of follow-up, with a cumulative incidence of 34.1% (95% CI: 26.1–42.7). Calf diarrhea, pneumonia, septicemia, dehydration, and navel ill were the encountered health problems consecutively. Among the potential risk factors, calves from Siyadeber Kebele (RR = 2.11, 95% CI: 1.13–3.94), calves housed with other livestock (RR = 2.05, 95% CI: 1.10–3.80), housed with their dam (RR = 1.92, 95% CI: 1.20–3.05), without bedding (RR = 1.89, 95% CI: 1.20–2.94), and calves whose dam age ranges from 5 to 8 years (RR = 1.87, 95% CI: 1.05–3.35) were found to be predictors of calf morbidity. In general, the high calf morbidity rates established in this study together with the alarming predictors of calf morbidity entail attention by the concerning bodies on proper management and improved health care so as to reduce the calf morbidity.

Bovine respiratory disease (BRD) cause-specific and overall mortality in preweaned calves on California dairies: The BRD 10K study

Mortality in preweaned dairy calves is a significant source of economic loss for dairy producers. In particular, bovine respiratory disease (BRD) is a leading cause of death in preweaned dairy calves. The objectives of this study were to investigate management practices and their effects on mortality, both that specifically attributed to BRD and overall mortality due to all causes, in preweaned dairy calves. Rates of failure of passive transfer of immunity (FPT) are also reported. The study consisted of a convenience sample of 5 dairies across California, selected based on management practices, calf records, location, and size. Trained study personnel performed comprehensive calf management surveys on every dairy at least once every season. Calves were enrolled in the study at birth and followed until weaning. Mixed-effect logistic regression models were specified for the outcomes all-cause mortality (any death before weaning) and mortality attributed to BRD. The 2 final models included a total of 11,470 calves that were born on the study dairies and followed until weaning. The study cohort's overall crude mortality was 2.8%, with crude mortality of individual dairies ranging from 1.7 to 7.2%. The proportion of mortality attributed to BRD was 19.3%, with a range of 0 to 27.1% on the study dairies. Increasing the frequency of changing maternity pen bedding was associated with a decreased risk of mortality due to BRD. Calves diagnosed with BRD in the spring had an increased risk of mortality compared with calves born in the summer; mortality in calves with fall and winter BRD diagnoses did not different significantly from that in summer. Season of mortality was not significant in either model. Feeding ≥5.7 L of milk per day per calf (vs. ≤3.7 L/d) decreased the risk of mortality in calves over 21 d of age. Twins had a 68% increased risk of all-cause mortality compared with calves born as singletons. Both mortality models showed an association between administration of a modified live vaccine in dams (targeting BRD pathogens) and a decreased risk of mortality in calves. Using a serum total protein cut-off of 5.2 g/dL, 16.8% of calves had FPT, with a mean serum total protein concentration of 5.94 ± 0.06 g/dL across all calves sampled.

Management factors associated with mortality of dairy calves in Finland: A cross sectional study

Mortality at herd level is an indicator of overall calf welfare on dairy farms. The aim of this cross sectional study was to identify management factors associated with calf mortality on dairy farms in Finland. Calf mortality data and information on management practices collected during farm visits and farmer interviews were analysed using linear models. The average size of 82 herds enrolled in the study was 125 ± 41 cows. The mortality risk of calves <7 days of age was 5 (or 5.2) ± 2.3% and was associated with larger herd size and the practice of not separating sick calves from other calves (6.0 ± 0.4 vs. 4.7 ± 0.3%; P < 0.05). The mortality risk of calves aged 7-180 days was 6 (or 5.7) ± 6.2% and increased with a shorter whole milk feeding period, longer period in the calving pen and lower average herd production level (P < 0.05). The mortality risk of calves was lower on farms where a veterinarian disbudded calves instead of farmer. Longer milk feeding and improved management of sick calves are recommended to reduce calf mortality. Specific management practices associated with lower mortality risk should be emphasised when advising farmers on how to enhance calf welfare.