Calf Mortality Research Articles

No long‐term effect of black bear removal on elk calf recruitment in the southern Appalachians

AbstractIn 2001 and 2002, 52 elk (Cervus canadensis; 21 males, 31 females), originally obtained from Elk Island National Park, Alberta, Canada, were transported and released into Cataloochee Valley in the northeastern portion of Great Smoky Mountains National Park (GRSM, Park), North Carolina, USA. The annual population growth rate (λ) was negative (0.996, 95% CI = 0.945–1.047) and predation by black bears (Ursus americanus) on elk calves was identified as an important determinant of population growth. From 2006 to 2008, 49 bears from the primary elk calving area (i.e., Cataloochee Valley) were trapped and translocated about 70 km to the southwestern portion of the Park just prior to elk calving. Per capita recruitment (i.e., the number of calves produced per adult female that survive to 1 year of age) increased from 0.306 prior to bear translocation (2001–2005) to 0.544 during years when bears were translocated (2006–2008) and λ increased to 1.118 (95% CI = 1.096–1.140). Our objective was to determine whether per capita calf recruitment rates after bear removal (2009–2019) at Cataloochee were similar to the higher rates estimated during bear removal (i.e., long‐term response) or if they returned to rates before bear removal (i.e., short‐term response), and how those rates compared with recruitment from portions of our study area where bears were not relocated. We documented 419 potential elk calving events and monitored 129 yearling and adult elk from 2001 to 2019. Known‐fate models based on radio‐telemetry and observational data supported calf recruitment returning to pre‐2006 levels at Cataloochee (short‐term response); recruitment of Cataloochee elk before and after bear relocation was lower (0.184) than during bear relocation (0.492). Recruitment rates of elk outside the removal area during the bear relocation period (0.478) were similar to before and after rates (0.420). In the Cataloochee Valley, cause‐specific annual calf mortality rates due to predation by bears were 0.319 before, 0.120 during, and 0.306 after bear relocation. In contrast, the cause‐specific annual mortality rate of calves in areas where bears were not relocated was 0.033 after the bear relocation period, with no bear predation on calves before or during bear relocation. The mean annual population growth rate for all monitored elk was 1.062 (95% CI = 0.979–1.140) after bear relocation based on the recruitment and survival data. Even though the effects of bear removal were temporary, the relocations were effective in achieving a short‐term increase in elk recruitment, which was important for the reintroduction program given that the elk population was small and vulnerable to extirpation.

Production systems and breeding practices of Begaria cattle breed as input for a community-based breeding program

This study aimed to describe the production systems and breeding practices of Begaria cattle breeds as a resource for community-based conservation and breeding program. A semi-structured questionnaire and focus group discussions were employed to identify and describe the breeding practice of the farmer. Three kebeles: Almahal, Fanguso, and Mankush were considered for the study. The data were analyzed using R software. Cattle were kept for a variety of reasons, including milk, breeding, meat, cash, and saving. It was typical throughout the study area to see herd mixing and keeping together (4.7 ± 0.33 herds on average), herd movement during the dry season, and breeding bull sharing (1.9 ± 1.55 shared bulls). During the summer season, cattle rearing in the areas was hindered by feed and water shortages. The breed's major reproduction constraints were abortion (24 %), repeat breeding (19), and calf mortality (14). The primary reason for keeping Begaria cattle was for milk (29 %), cash (26), meat (22), and breeding (0.22). The average age at first calving (AFC), calving interval (CI) and milk yield per day of the breed were 41.5 ± 1.63, 16.0 ± 0.43 months, and 3.2 ± 0.12 L respectively. The average age of breeding bull selection was 3 ± 0.1 years, and it was based on several criteria, including their phenotype, growth, and white coat colour. Based on the current findings, it is recommended that a multi-trait selection program be designed with full stakeholder participation.

OUTBREAK PREDICTION METHODS AND MEASURES TO CONTROL THE SPREAD OF BOVINE VIRAL DIARRHEA IN KAZAKHSTAN

Bovine viral diarrhea (BVD) is a contagious, acute disease of cattle that is reported in many countries around the world. BVD is caused by pestiviruses Pestivirus A and Pestivirus B belonging to the genus Pestivirus, family Flaviviridae. The disease causes significant economic damage to livestock breeding, leading to reproductive dysfunction (reduced reproductive capacity, delayed births, early embryonic death, abortion, congenital anomalies) and decreased productivity (morbidity, high calf mortality, decreased milk yield). In recent years, outbreaks of BVD have occurred in several regions of Russia and China bordering Kazakhstan, indicating a high risk of introducing the infection into the country. Although Kazakhstan is officially considered free from BVD, there are numerous indications that this infection is present in many regions of the country, which requires the use of effective control measures in regions at risk for infection. This article provides methods for assessing the epizootological situation and forecasting outbreaks, as well as recommendations for carrying out veterinary measures and monitoring BVD in Kazakhstan, based on the results of a monitoring study of the epizootological situation and an analysis of the risks of the spread of BVD in Kazakhstan in 2021-2023

Pathological and genetic characterization of foot and mouth disease viruses collected from cattle and water buffalo in Egypt.

Foot-and-mouth disease (FMD), a highly contagious viral disease caused by FMD virus (FMDV) that threatens Egypt's livestock industry. FMDV causes severe economic losses in the livestock, with restriction of international trade from endemic regions. Surveillance for FMDV serotypes circulating in Egypt is urgently needed to assess the epidemiological situation in the country. FMD outbreaks reported in Egypt in between December 2016 and January-March 2017. A cross-sectional study was conducted to identify the FMDV serotypes responsible for the outbreaks and to collect information on the virus's morphopathological effects. Postmortem tissue and clinical samples (oral swabs, vesicular fluids from ruptured vesicles, and blood) were collected from recently deceased and infected animals. Pathological examination revealed classical FMD lesions as vesicular and erosive lesions on epithelial tissues with non-suppurative lymphoplasmacytic myocarditis. Phylogenetic and sequencing analyses demonstrated that FMDV serotype O, EA-3 topotype, VP1 is the prevalent serotype responsible for the pathological alterations and the high mortality in young calves, adult cattle, and water buffalo. The outcomes indicate continuous mutations in the circulating FMDV, which result in the occasional failure of vaccination. Based on these findings, extensive continuous monitoring and serotyping of the existing circulating FMDV isolates and regular vaccination with reevaluation of the currently used vaccine in Egypt are recommended to prevent the recurrence of such outbreaks.

Isolation of Common Calves Diarrhoea Causing Bacterial and Protozoal Enteropathogen and Associated Risk Factors from the Dairy Farms in and Around Assela Town Arsi Zone, Oromia Regional State of Ethiopia

Calf morbidity and mortality resulted from diarrhea hinder the replacement of older cows by calves and lower economic benefit from the secretor in Ethiopia. Bacterial and Protozoal infectious disease were the main causes of calves’ diarrhea in dairy farms. The aim of the current study was conducted to isolate calf’s diarrhea causing Bacterial and Protozoal infection and asses the risk factors associated with it in and around the Assela town. Accordingly, 26 small, medium, and large-scale dairy farms were purposively selected for collection of faecal and serum samples and risk factors related information diarrhoeic calves. From 108 calves, 2 × 10 g of feces and 10 mL of jugular blood from each calf were collected. Bacterial culturing and serodiagnosis and protozoal microscopic examination were conducted. From 26 small, medium, and large dairy farms in the Assela region were investigated for the percentage of significant enteropathogens in diarrhoeal calves over six months. They contained proportions of E. coli, Eimeria, Cryptosporidium, Giardia and Salmonella Typhimurium of 55 (50.9%), 42 (38.9%), 23, 8 (7.4%) and 3‘(2.8%), respectively. All risk factors assessed had equal impact on the occurrence of Enteropathogen hence there was no significant difference among them (P-value > 0.05). the high calf Diarrhea causing Enteropathogen 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 to reduce the incidence of Calves diarrhea.

A systematic review of the relationship between housing environmental factors and bovine respiratory disease in preweaned calves – Part 1: Ammonia, air microbial count, particulate matter and endotoxins

Bovine respiratory disease (BRD) is one of the leading causes of mortality and morbidity in calves across diverse management systems. Despite expert opinion often citing the influence of housing environment on the level of respiratory disease in calf groups, there have been few reviews of environmental factors that predispose to BRD. This systematic review was undertaken to identify the measurable environmental variables associated with respiratory disease in housed preweaned calves. To achieve this Pubmed, CAB Direct and Scopus databases were searched. To be considered for inclusion, publications had to be fully published in English, published before 24 November, 2022 and include at least one measurable/ manipulated environmental variable and a standardized method of BRD detection.Twelve publications were included in this review. These examined a wide range of risk factors including air microbial count (four publications), air particulate matter (one publication); air endotoxins (one publication) and air ammonia (four publications). From the included publications, a statistically significant relationship to BRD was identified in 2/4 examining air microbial count, 1/1 examining air particulate matter, 1/1 examining air endotoxins and 2/4 examining air ammonia. This review indicated a paucity of evidence from the peer-review literature demonstrating a significant association between the many investigated exposure factors and BRD occurrence. An optimal environment for housed calves could not be clearly identified in this review.

Risk factors and genetic parameter estimates for preweaning survival of Fogera calves

This study utilised mortality records of 1 043 Fogera calves maintained at Andassa Livestock Research Center from 1984 to 2021 to investigate the factors that influence survival and estimate genetic parameters for the preweaning survival of Fogera calves. Survival was defined as the probability of surviving in a given length of time. Survival analysis was done using the Weibull proportional hazard model with Survival Kit version 6.1 software. Genetic variance and heritability estimates were estimated using the sire model. The proportion of right-censored calves up to 1, 4, and 8 months of age was 90.8, 87.8, and 83.5%, respectively. Around 55.8% of all deaths (16.5%) occurred up to one month of age. In addition to birth year, sex, season, and weight at birth were the most important risk factors for calf mortality. The heritability estimates for the survival of calves at 1, 4, and 8 months of age were 0.26 ± 0.14, 0.22 ± 0.13, and 0.38 ± 0.18, respectively. Moderate heritability was estimated at the age of eight months, implying that the inclusion of survival traits in the selection criteria and inclusion in the breeding goal will enhance the preweaning survival rate of calves. Similarly, higher differences in estimated breeding values of sires for survival suggest that the selection of sires with higher estimated breeding values could improve the survival potential of calves. The decreased genetic trend of 3.34% year−1 for the survival potential of Fogera calves during the study periods suggested that survival traits should be included in the breeding goal to reduce the mortality rate.

Risk factors associated with calf mortality in Western Canadian cow-calf operations.

This study examined the influence of management practices and herd demographics on calf mortality proportions in Western Canadian cow-calf operations, utilizing data from the second Western Canadian Cow-calf Survey. The survey was conducted between October 23, 2017, and February 28, 2018. The survey, which was open to all cow-calf producers across Western Canada, provided producer-reported data regarding calf death loss and corresponding herd-level factors. A fractional logit model was employed to identify significant factors associated with calf mortality proportions. The findings revealed that shorter breeding seasons (<63 days), calves born within the same season, and regular pregnancy checks for breeding females were negatively associated with calf mortality proportions. Conversely, regular breeding soundness evaluations for breeding bulls, traditional weaning methods, and vaccinating heifers for scours showed positive associations with increased calf mortality proportions. Herd operations where dams were vaccinated against clostridial and bovine respiratory diseases had lower calf mortality proportions. Notably, operations with experienced primary decision-makers holding off-farm jobs had lower predicted calf mortality proportions compared to those managed by full-time cattle producers. Higher predicted calf mortality proportions were observed in operations employing a backgrounding system. The study's limitations included potential biases due to its cross-sectional nature and reliance on producer-reported data, which might lead to an underestimation of calf mortality proportions. Also, the limited sample size and missing data might have affected the statistical significance of some variables. This study contributed to the research on cow-calf operation by using a fractional logit model to analyze the correlation between risk factors and calf mortality proportions, and by identifying novel herd-level risk factors. It provided a basis for future research aimed at developing empirically-based management strategies to optimize calf health outcomes.

Decreased gene expression of RIPK1 and RIPK3, necroptosis players, in calves with sepsis

Background With the increase in the world population, the need for livestock-based nutrition is also increasing. In addition, the livestock sector becomes more important as it contributes to the economy However, sepsis has high morbidity and mortality rate in newborn calves and can cause severe economic losses. Therefore, new biomarkers to distinguish sepsis from other diseases are urgently needed in veterinary medicine. In the present study, we investigated for the first time the gene expression levels of necroptosis members, including RIPK1 and RIPK3, and one of the NF-kB activators RIPK2, in calves with sepsis.&#x0D; Methods and results We examined the mRNA levels of RIPK1, RIPK3, and RIPK2 using qPCR in 10 healthy Holstein calves and 20 Holstein calves with sepsis due to suffering from enteritis infection between 1-20 days of age. The hematologic parameters, including leukocytes, erythrocytes, hemoglobin, hematocrit, and platelets, were evaluated in the calves included in this study. The results showed that calves with sepsis had prominently lower mRNA levels of RIPK1 and RIPK3 than those in healthy calves. Besides, RIPK2 mRNA expression was absent in healthy calves and calves with sepsis. &#x0D; Conclusions In veterinary medicine decreased RIPK1 and RIPK3 mRNA levels might be biomarkers to diagnose sepsis in calves.

Failure of Passive Immunity Transfer Is Not a Risk Factor for Omphalitis in Beef Calves.

Omphalitis is the third most frequent disease in newborn calves after neonatal diarrhea and bovine respiratory disease (BRD), but limited data on the prevalence and risk factors are available in the literature. Failure of passive immunity transfer (FPIT) is recognized as a major risk factor for diseases and mortality in calves. However, the association between omphalitis and FPIT remains poorly described. To assess this association, 964 suckler beef calves from 22 farms were included in a longitudinal cohort study for 5 months. Each calf was examined twice (mean ages: 4.4 and 11.1 days old) to diagnose omphalitis through clinical examination and ultrasonographic evaluation (USE) if necessary. Measurements of the total solids percentage (TS-%Brix) and total protein (TP) were performed on the serum during the first visit to evaluate the calves' passive immunity status. FPIT (fair and poor) was defined as serum %Brix < 8.1 or TP < 5.1 g/dL; among calves with omphalitis, 14% had FPIT and among calves without omphalitis 12% had FPIT. The omphalitis prevalence was 32.3% in calves without any other disease (overall prevalence of 30.9%). No statistical association between the prevalence of omphalitis and FPIT was observed. Further research is needed to identify the risk factors and promote the prevention measures for omphalitis in cow-calf systems, such as calving difficulty, hygiene of housing, and navel disinfection.

Metagenomic and metabolomic analyses reveal the role of gut microbiome-associated metabolites in diarrhea calves.

Calf diarrhea is a multifactorial disease that affects the cattle industry and accounts for more than 50% of calf mortality. Although there is evidence of an association between altered gut microbiota and diarrhea, remarkably little is known about the microbial and metabolic mechanisms underlying the link between gut microbiota dysbiosis and the occurrence of calf diarrhea. Here, we performed fecal metagenomic and metabolomic studies on fecal samples from diarrheic and healthy calves of Xia-nan cattle breed. Results revealed that composition of the gut microbiome and metabolome was remarkably altered in diarrheic calves, and gut microbial alterations were associated with diarrhea and linked to the changes in metabolites. Metabolite profiles showed that diarrheic calves exhibited a marked decrease in some purines (adenosine, adenine, 2'-deoxyguanosine, allantoate, deoxyinosine, and deoxyguanosine) and arachidonic acid (prostaglandin F2α and prostaglandin E2) compared to healthy calves. Purine-producing microbial species, including Lactiplantibacillus plantarum, Campylobacter coli, Treponema porcinum, Klebsiella pneumoniae, and Phocaeicola coprophilus, were significantly reduced in diarrheic calves compared to healthy calves, whereas the arachidonic acid-producing species such as Neisseria gonorrhoeae, Staphylococcus aureus, and Clostridiales bacterium exhibited a marked increase. These microbial signatures were closely associated with the metabolic dysbiosis of purine and arachidonic acid in diarrhea calves. Our study showed that gut microbiota-driven metabolic disorders of purine or arachidonic acid were associated with calf diarrhea. The findings prove that altered gut microbiota plays a role in diarrhea pathogenesis and indicate that gut microbiota-targeted therapies could be useful for both prevention and treatment of diarrhea. IMPORTANCE Calf diarrhea is of great concern to the global dairy industry as it results in significant economic losses due to lower conception rates, reduced milk production, and early culling. Although there is evidence of an association between altered gut microbiota and diarrhea, remarkably little is known about the microbial and metabolic mechanisms underlying the link between gut microbiota dysbiosis and the occurrence of calf diarrhea. Here, we used fecal metagenomic and metabolomic analyses to demonstrate that gut microbiota-driven metabolic disorders of purine or arachidonic acid were associated with calf diarrhea. These altered gut microbiotas play vital roles in diarrhea pathogenesis and indicate that gut microbiota-targeted therapies could be useful for both prevention and treatment of diarrhea.

Genome-wide association study identifies functional genomic variants associated with young stock survival in Nordic Red Dairy Cattle

Identifying quantitative trait loci (QTL) associated with calf survival is essential for both reducing economic loss in cattle industry and understanding the genetic basis of the trait. To identify mutations and genes underlying young stock survival (YSS), we performed GWAS using de-regressed estimated breeding values of a YSS index and its component traits defined by sex and age in 3,077 Nordic Red Dairy Cattle (RDC) bulls and 2 stillbirth traits (first lactation and later lactations) in 5,141 RDC bulls. Two associated QTL regions on Bos taurus autosome (BTA) 4 and 6 were identified for the YSS index. The results of 4 YSS component traits indicate that same QTL regions were associated with bull and heifer calf mortality, but the effects were different over the growing period and suggested an additional QTL on BTA23. The GWAS on stillbirth identified 3 additional QTL regions on BTA5, 14, and 24 compared with YSS and its component traits. The conditional test of BTA6 showed at least 2 closely located QTL segregating for YSS component traits and stillbirth. We found 2 independent QTL for stillbirth on BTA23. The post-GWAS revealed LCORL, PPM1K, SSP1, MED28, and LAP3 are putative causal genes on BTA6, and a frame shift variant within LCORL, BTA6:37401770 (rs384548488) could be the putative causal variant. On BTA4, the GRB10 gene is the putative causal gene and BTA4:5296018 is the putative causal variant. In addition, NDUFA9 and FGF23 on BTA5, LYN on BTA14, and KCNK5 on BTA23 are putative causal genes for QTL for stillbirth. The gene analysis also proposed several candidate genes. Our findings shed new light on the candidate genes affecting calf survival, and the knowledge could be utilized to reduce calf mortality and thereby enhance welfare of dairy cattle.

Association between transfer of passive immunity, health, and performance of female dairy calves from birth to weaning

The objective of this observational study was to compare calf health, average daily weight gain, and calf mortality considering the proposed categories of transfer of passive immunity (TPI) by the consensus report of Lombard et al. (2020). The consensus report defines 4 categories of passive immunity (excellent, good, fair, and poor) of calves obtained after colostrum ingestion. The association between the 4 TPI categories was analyzed on calf health (i.e., hazards for morbidity and mortality), and average daily weight gain (ADG) of female Holstein Friesian calves during the first 90 d of age. A further aim of this study was to examine the effects of calving-related factors, such as dystocia or winter season, on TPI status. We hypothesized that calves with excellent TPI have greater ADG, lower risks for infectious diseases such as neonatal diarrhea, pneumonia, and omphalitis, and lower mortality rates. This observational study was conducted from December 2017 to March 2021. Blood was collected from 3,434 female Holstein Friesian dairy calves from 1 commercial dairy farm. All female calves aged 2 to 7 d were assessed for TPI status by determination of total solids (TS) in serum via Brix refractometry by the farm personnel once a week. Passive immunity was categorized according to Lombard et al. (2020) with excellent (≥9.4% Brix), good (8.9-9.3% Brix), fair (8.1-8.8% Brix), or poor TPI (<8.1% Brix). For the analysis of ADG and calving ease 492 or 35 calves had to be excluded due to missing data. The distribution of calves according to TPI categories was as follows: 4.8% poor (n = 166), 29.5% fair (n = 1,012), 28.3% good (n = 971), and 37.4% excellent (n = 1,285). From the calving-related factors, parity of the dam, calving ease, birth month, calving assistance by different farm personnel, and day of life for TPI assessment were significantly associated with TS concentration. Out of 3,434 calves, 216 (6.3%) had diarrhea, and 31 (0.9%) and 957 (27.9%) suffered from omphalitis and pneumonia during the first 90 d of life, respectively. Overall, the morbidity during the preweaning period was 32.6% (n = 1,118), and the mortality was 3.1% (n = 107). The ADG was 0.90 ± 0.15 kg with a range of 0.32 to 1.52 kg. The Cox regression model showed that calves suffering from poor TPI tended toward a greater hazard risk (HR) for diarrhea (HR = 1.57, 95% CI: 0.92-2.69) compared with calves with excellent TPI. Calves suffering from TPI had a greater HR for pneumonia (HR = 2.00, CI: 1.53-2-61), overall morbidity (HR = 1.99, CI: 1.56-2.55), and mortality (HR = 2.47, CI: 1.25-4.86) in contrast to excellent TPI. Furthermore, calves with good and fair TPI had significantly greater HR for pneumonia (good TPI: HR = 1.35, CI: 1.15-1.59; fair TPI: HR = 1.41, CI: 1.20-1.65) and overall morbidity (good TPI: HR = 1.26, CI: 1.09-1.47; fair TPI: HR = 1.32, CI: 1.14-1.53) compared with the excellent TPI category. Average daily weight gain during the first 60 d of life was associated with TPI categories. Calves with excellent and good TPI status had ADG of 0.90 ± 0.01 kg/d and 0.92 ± 0.01 kg/d (mean ± SE), respectively. The ADG of calves with fair TPI status was 0.89 ± 0.01 kg/d, and calves suffering from poor TPI had 0.86 ± 0.01 kg/d. Average daily weight gain differed in calves with poor TPI compared with the other categories. Fair and excellent TPI differed additionally from good TPI. We found no statistical difference between the TPI categories fair and excellent. In conclusion, poor TPI was associated with higher morbidity and mortality during the first 90 d of life. Furthermore, calves with fair, good or excellent TPI had greater ADG.

Differential gene expression in peripheral leukocytes of pre-weaned dairy calves with respiratory disease

Bovine respiratory disease (BRD) is a leading cause of calf morbidity and mortality in both beef and dairy sectors of the United States cattle industry resulting in financial losses and compromised welfare. Differential gene expression (DGE) al­lows detailed insight into individual immune responses and can identify enriched pathways and biomarkers that contrib­ute to disease susceptibility and outcome. Differential expres­sion of genes related to innate immune function has been well documented in both feedlot and post-weaned dairy cattle with experimentally induced or naturally occurring BRD. However, little is known regarding DGE in pre-weaned Holstein calves. Therefore, the aims of this study were to evaluate gene expres­sion in peripheral leukocytes relative to BRD diagnosis, dis­ease progression and age progression in Holstein heifer calves throughout the preweaning period.

Study of calf health and management problems in urban and per-urban dairy farms of selected districts of East Wollega Zone of Oromia Regional State, Western Ethiopia

Calf care is not only essential for the sustenance of the dairy industry but is also essential for preserving and maintaining good-quality of germplasm. On the contrary, high levels of calf mortality have limited dairy herd expansion and genetic improvement in the study area. Therefore, the study was developed to evaluate the existing calf health and management problems and to assess the level of farmers’ knowledge and calf health and management practices in the study areas. Thus, a cross-sectional study design was used and the study districts and peasant association were selected purposely where as the individual household was selected randomly using a systematic random sampling method. A total of 50 households were selected from the three districts and a detailed questionnaire survey format was designed to generate baseline information related to the calf health management system and major calf health problems. As the study result indicated diseases like blackleg, pneumonia, and internal and external parasites were the most dominant calves’ health problems. About 50% of the respondents informed that most calf mortalities occurred due to pneumonia, blackleg, starvation, heartwater, diarrhea, and bloat. Even though all calves were getting access to colostrum feeding, they do not access the optimum level, and regarding calves’ feed natural grass is categorized in the first rank where as concentrated feeds (ground maize, grain, noug cake) and food left over (local brewery by product and straw) were placed in the second and third rank, respectively. And all farmers in the study area have access to veterinary services, however, the accessibility is not uniform among the farmers. In general, as the study revealed there has been poor management practice regarding both feeding and housing of calves in the study area. Therefore, identifying economically important animal diseases and designing strategic preventive and control measures and improvement of calf management practices through awareness creation among farmers is valuable.

Invited Review: Bovine neonatal morbidity and mortality - causes, risk factors, incidences, sequelae and prevention.

The neonatal period may be defined as the first month of the calf's life; it may be considered part of the fourth trimester. It is the most hazardous due to the immaturity of the neonate's immune system and the environmental challenge from infections, the main causes of both bovine neonatal morbidity and mortality. The five most common morbidities causing mortality in neonatal calves are, in descending order, gastro-intestinal infections, respiratory infections, abomasal disorders, umbilical infections and developmental abnormalities. This review describes the aetiology, incidence, risk factors and sequelae of these common morbidities and highlights current preventive strategies both at farm- and national-levels.

Shiga Toxin-Producing Escherichia coli (STEC) Associated with Calf Mortality in Uruguay.

In Uruguay, the mortality of dairy calves due to infectious diseases is high. Escherichia coli is a natural inhabitant of the intestinal microbiota, but can cause several infections. The aim of the work was to characterize E. coli isolates from intestinal and extraintestinal origin of dead newborn calves. Using PCR, virulence gene characteristics of pathogenic E. coli were searched. The pathogenic E. coli were molecularly characterized and the phylogroup, serogroup and the Stx subtype were determined. Antibiotic susceptibility was determined using the Kirby-Bauer disk diffusion method and plasmid-mediated quinolone resistance (PMQR) genes with PCR. Finally, clonal relationships were inferred using PFGE. Gene characteristics of the Shiga toxin-producing E. coli (STEC), Enteropathogenic E. coli (EPEC) and Necrotoxigenic E. coli (NTEC) were identified. The prevalence of the iucD, afa8E, f17, papC, stx1, eae and ehxA genes was high and no f5, f41, saa, sfaDE, cdtIV, lt, sta or stx2 were detected. The prevalence of STEC gene stx1 in the dead calves stood out and was higher compared with previous studies conducted in live calves, and STEC LEE+ (Enterohemorrhagic E. coli (EHEC)) isolates with stx1/eae/ehxA genotypes were more frequently identified in the intestinal than in the extraintestinal environment. E. coli isolates were assigned to phylogroups A, B1, D and E, and some belonged to the O111 serogroup. stx1a and stx1c subtypes were determined in STEC. A high prevalence of multi-resistance among STEC and qnrB genes was determined. The PFGE showed a high diversity of pathogenic strains with similar genetic profiles. It can be speculated that EHEC (stx1/eae/ehxA) could play an important role in mortality. The afa8E, f17G1 and papC genes could also have a role in calf mortality. Multidrug resistance defies disease treatment and increases the risk of death, while the potential transmissibility of genes to other species constitutes a threat to public health.

CROSSBRED CALF MORTALITY AND MANAGEMENTAL PRACTICES IN OPERATIONAL AREA OF DAIRY VIGYAN KENDRA

The study objective is to know the prevailing crossbred calf mortality &amp; managemental practices in the operational area of Dairy Vigyan Kendra (DVK), Vejalpur, Gujarat, India. A total of 300 crossbred cattle owners from 30 villages of 10 talukas were selected using the simple random sampling method for the study from August to December 2022. The data were collected based on the pre-tested structured interview schedule. Overall crossbred calf mortality was observed 33.70 per cent in the study area. There was a higher mortality rate in male calves (56.78%) than in female crossbred calves (16.98%) due to limited attention towards the male calf. The mortality rate was recorded higher during the first three months of age (70.78%) and during the monsoon (39.72%). The primary reason for calf mortality was malnutrition/ male calf negligence. Farmers urgently need extension services on scientific calf rearing practices such as providing concentrate feed, cutting navel cord with the sterilized object, providing milk as per body weight, on-time colostrum feeding, provision of milk replacer, calf starter, salt, mineral mixture, deworming, and vaccinations against diseases.

Prevalencia puntual de enteropatógenos basada en ELISA en terneros diarreicos en la región de Anatolia Central de Turquía

This study reports potential causes of diarrhea in neonatal calves, leading to calf mortality, from the selected population of the three Provinces of Turkey. A total of 300 fecal samples were collected purposively from diarrheic neonatal calves distributed to the three age groups (1–14 days, 15–29 days, and 30–90 days), from Konya, Karaman, and Aksaray Provinces of Turkey. The fecal specimens were examined for the existence of Cryptosporidium spp., rotavirus, coronavirus, and Escherichia coli by commercially available capture direct enzyme linked immunosorbent assay (ELISA) kit. The oocysts and coproantigens of Cryptosporidium were identified in 109 (36.3%) and 156 (52%) of the 300 calves, respectively. While, rotavirus, E. coli and coronavirus antigens were detected (P&lt;0.05) in 57 (19%), 17 (5.6%) and 6 (2%) calves, respectively. Mixed infection of the study pathogens has also been found in this report. These results provide a baseline information on the frequent causes of neonatal calf diarrhea in the studied Provinces which can be used to develop a prophylaxis plan.

Economics of Yak herding in the Kanchenjunga landscape of the Eastern Himalayas

Yak herding is one of the oldest market-based traditions, which is part of an integrated social-ecological system. But, it is at risk of extinction as yak herders are gradually shifting towards alternative occupations. The discontinuation of herding may have several implications such as loss of culture and degradation of the rangeland ecosystem. Though yak herding is not limited to the financial aspect of herding, this is considered a main cause of the discontinuation. Therefore, it is important to understand the economics of yak herding. A benefit–cost analysis of yak herding was carried out based on the interviews with 60 yak herders in the Kanchenjunga landscape, Nepal. The results indicate that yak herding is not financially attractive. High mortality of calves and adults is threatening this occupation, and degrading rangelands are increasing the costs. Yak herding generates substantial amount of social and ecological benefits in terms of preserving culture, maintaining rangeland ecosystems and curbing illegal activities. If these benefits are included, then the benefit–cost ratio and internal rate of return would be 1.32 and 10.44 respectively. Since yak herding generates low direct profits and requires herders to stay in remote areas, there is a high risk of discontinuation of this profession by successive generations of youth. This study suggests to improve rangeland management through prescribed burning and provisioning of health services, particularly in summer pastures and incentivize yak herders for generating positive externalities.