Calf Mortality Research Articles

Utility of postmortem bacterial culture of abdominal organs at autopsy of young calves.

Postmortem bacterial culture is controversial in human medicine, and veterinary-specific research in this area is lacking. To address this knowledge gap, we cultured liver, kidney, and spleen individually from on-farm calf mortalities to determine the number of bacterial species present, concordance between organ cultures, and agreement with gross and histologic findings. We hypothesized that the spleen, a filtering organ, would be the most useful organ with the least amount of postmortem contamination given that it does not have a direct conduit to a bacterial population. Fresh liver, kidney, and spleen were collected for culture from 30 calves 5-28-d-old with various causes of mortality. Bacterial growth of ≥2 species was observed in ~48% of cultures, with Escherichia coli and Streptococcus spp. being most frequent. One bacterial species was present in 20% of cultures, with E. coli predominating. No growth was observed in ~32% of cultures. In 43% of cases, there was agreement in the culture results for all 3 organs; however, the majority were mixed bacterial growth. The best agreement was observed when there were no gross and/or histologic septic lesions in target organs and no bacterial growth on culture. The spleen was not helpful in determining bacterial significance in comparison to kidney or liver.

Longitudinal study of calf morbidity and mortality and the associated risk factors on urban and peri-urban dairy farms in southern Ethiopia

BackgroundCalf morbidity and mortality are among the leading causes of economic losses on dairy farms around the world. Poor calf management practices exacerbate the problem in developing countries like Ethiopia. This prospective, longitudinal study was conducted on 70 selected dairy farms in southern Ethiopia with the aim of estimating calf morbidity and mortality rates, identifying the associated risk factors and determining whether the mortality rate is above economically tolerable levels. For this purpose, a total of 274 calves on 70 farms were followed up every two weeks from birth to six months of age for major clinical health problems and deaths.ResultsThe study found a morbidity rate of 13.2 cases and a mortality rate of 3.8 cases per 100 calf-months at risk in the study calves. The cumulative incidence of morbidity and mortality was also found to be 40.29% and 12.85%, respectively. Diarrhea was the leading cause of morbidity and mortality in calves, accounting for 71.3% and 62.1% of all morbidity and mortality, respectively. In a multivariable Cox regression analysis, the risk of morbidity was significantly (p = 0.022) higher in calves born to dystocia-affected dams (HR = 2.4) and on farms where dairy farming is the farmers’ secondary source of income (HR = 1.7). However, the risk of morbidity was significantly (p < 0.001) lower in calves older than three months (HR = 0.22), female calves (HR = 0.57), calves raised by farmers who had completed secondary school (HR = 0.26) or college education (HR = 0.30). Similarly, calves aged over three months (HR = 0.14), calves separated from their dams only after ingestion of colostrum (HR = 0.40) and calves owned by farmers who completed secondary school (HR = 0.08) or college education (HR = 0.13) all had lower mortality rates than other groups. On the other hand, calves born to cows with dystocia were 5.2 times more likely to die.ConclusionThe study concluded that calf morbidity and mortality rates in the study area are higher than economically tolerable levels and therefore it is recommended to raise awareness among farmers to improve calf management practices.

Acute Kidney Injury Is Associated with Higher Serum Cys-C and NGAL Concentrations, and Risk of Mortality in Premature Calves with Respiratory Distress Syndrome.

The purpose of the present study was to establish the development of acute kidney injury (AKI) and evaluate the usefulness of kidney-specific biomarkers in diagnosing AKI in premature calves with respiratory distress syndrome (RDS). Ten-term healthy and 70 premature calves with RDS were enrolled. Clinical examination, blood gases, and chemical analysis were performed at admission and 72 h. Serum concentrations of blood urea nitrogen (BUN), creatinine (Cre), phosphorus (P), cystatin-C (Cys-C), neutrophil gelatinase-associated lipocalin (NGAL), uromodulin (UMOD), and liver-type fatty acid-binding protein (L-FABP) were measured to evaluate kidney injury. Our findings showed that 38.5% of the premature calves with RDS developed AKI. The RDS-AKI group had a 4-fold higher mortality risk than the RDS-non-AKI group. Cys-C, with 90% and 89% specificity, and NGAL, with 100% sensitivity and 85% specificity, were the most reliable biomarkers to determine AKI in premature calves. The usefulness of any biomarker to predict mortality was not found to be convincing. In conclusion, AKI can develop as a consequence of hypoxia in premature calves and may increase the risk of mortality. In addition, serum Cys-C and NGAL concentrations may be useful in the diagnosis of AKI in premature calves with RDS.

Calf circumference change and all-cause mortality among community-dwelling Chinese older people

Previous studies have described an association between single time point calf circumference (CC) and mortality. Evidence of associations between CC change and mortality is lacking. We aimed to determine the relationship between the CC change over time and all-cause mortality. We conducted a retrospective cohort study of 906 participants in the 2014-2018 Chinese Longitudinal Healthy Longevity Survey (CLHLS). Restricted cubic splines were used to analyze associations between the relative CC change (exposure) and all-cause mortality (primary outcome). When there was evidence of non-linearity, a piecewise Cox regression model was next fitted, adjusting for sociodemographic characteristics, health behaviours, health status and baseline CC. The mean (SD) age was 83.8 (12.2) years old, and 50.2% (455/906) of participants were male. We observed a U-shaped association between the relative CC change (%) and all-cause mortality (P for non-linearity <0.001). Participants with stable CC over time had the lowest risk of death. After adjusting for covariates, when CC decreased over time, the hazard ratio per 10% higher in CC change was 1.32 (1.01-1.69). When CC increased over time, the hazard ratio per 10% higher in CC change was 1.35 (1.10-1.66). Stable CC over time was associated with the lowest mortality risk. Our findings indicate the practical significance of monitoring CC change in older adult.

DETECTION OF ELEPHANT ENDOTHELIOTROPIC HERPESVIRUS 1A IN ARCHIVAL TISSUE USING RNASCOPE® IN SITU HYBRIDIZATION.

Hemorrhagic disease due to elephant endotheliotropic herpesvirus infection (EEHV-HD) is an important cause of calf mortality in managed and free-ranging Asian (Elephas maximus) and African elephant (Loxodonta spp.) populations. Consequently, infection has profound implications for elephant population growth and sustainability. The mechanisms of disease caused by EEHV (i.e., infection, dissemination, shedding, latency) are relatively undefined, in part because of a lack of robust validated assays for detecting viral gene products in relevant samples. To address this issue, we used RNAscope® in situ hybridization (ISH) based on EEHV1A DNA polymerase and terminase genes to detect EEHV1A RNA in archival formalin-fixed, paraffin-embedded Asian elephant heart and tongue from PCR-confirmed cases (n = 4) of EEHV-HD and Asian elephants (n = 2) that died from other causes. EEHV1A-positive cases had positive hybridization signal in endothelial cell nuclei of both tissues for both DNA polymerase and terminase. EEHV-negative cases lacked signal. In positive cases, the number of positive nuclei was manually assessed to provide an estimate of the viral load and compare sensitivity of the two probes. In all cases, heart had greater signal than tongue for both probes (Wilcoxon rank test; P ≤ 0.01). Overall, terminase hybridization signal was greater than DNA polymerase signal (Wilcoxon rank test; P ≤ 0.01). Results indicate RNAscope ISH is a valuable tool for detection of EEHV in archival samples and for confirming infection. Additionally, the terminase gene is the optimal target and heart is preferable to tongue for detection in cases of EEHV-HD. Results will inform future investigations of viral tropism in EEHV-HD cases due to EEHV1A.

Epidemiology of Rotavirus Infection in Dairy Calves in Central Ethiopia

Rotavirus is a major pathogen responsible for diarrheal disease in calves and neonates resulting in loss of productivity and economic losses in dairy farms in developed and developing countries. In Ethiopia, the diarrheal disease caused by Rotavirus is not so far studied adequately. Across-sectional study was conducted from October 2019 to May 2020 to estimate the prevalence, assess associated factors, and isolate Rotavirus in calves below two months of age in the central part of Ethiopia, namely Holeta, Sululta, Bishoftu, and Sebeta. A total of 404 fecal samples, comprising 213 diarrheic and 191 non-diarrheic cases, were collected from calves of less than two months of age by simple random sampling technique. Rotavirus infection was detected using antigen detection Enzyme-linked immunosorbent assay technique. All samples positive for ELISA were propagated in Madin Darby bovine kidney cells. Data was analyzed using STATA version 13. Fisher’s exact test and logistic regression analysis were used to determine the association between prevalence of rotavirus and potential risk factors. An overall rotavirus prevalence of 1.24% (95%CI 0.40 – 2.86%) was found. The prevalence of rotavirus in diarrheic calves (1.41%) was not significantly different from the prevalence of rotavirus in non-diarrheic calves (1.04%) (p&gt;0.05). Similarly, the origin, breed, sex, age, management, and type of farm had no significant association with the prevalence of rotavirus infection of calves (p&gt;0.05). After 3 subsequent passages, progressive cytopathic effect i.e. Cell swelling and obscure cell boundaries, detachment and floatation of cells, cytoplasmic vacuolationas, increased cell granularity and cytoplasmic stranding were observed in all samples. The presence of rotavirus in dairy calves might entail morbidity and mortality in calves. Moreover, rotavirus infection might also lead to zoonotic transmission. Therefore, further detailed molecular epidemiological studies are warranted. Good hygienic and husbandry practices are essential to limit the spread of infection.

An investigation into potential genetic predictors of birth weight in tropically adapted beef cattle in northern Australia

Context Birth weight can be an important trait in beef cattle through its association with dystocia and increased likelihood of calf and cow mortality. Recording large numbers of birth weights in beef cattle to obtain a suitable genetic evaluation has often been hard to achieve. Aims We assess if coronet circumference measurements taken at birth and weights and coronet circumference measured post-birth are suitable predictors of birth weight for use in genetic evaluation in northern Australian tropically adapted beef breeds. Methods Animals were recorded at birth for weight (N = 5352) and coronet circumference (N = 2552), at 3 months of age for the liveweight (N = 2848) and coronet circumference (N = 2855) and liveweight at 6 months (N = 4929). Data were from three tropically adapted beef cattle breeds (viz. Brahman, Droughtmaster and Santa Gertrudis) recorded in two northern Australia herds. Genetic parameters were estimated from a pooled dataset containing all three breeds. Results Birth weight had an estimated direct and maternal heritability of 0.51 (0.04) and 0.14 (0.02) respectively. Coronet circumference also had high heritabilities, with estimates at birth and 3 months of 0.50 (0.07) and 0.55 (0.06) respectively. The estimated genetic correlation between birth weight and coronet circumference measured at birth was 0.86 (0.03). Birth weight genetic correlations were 0.75 (0.05) with 3-month weight, 0.69 (0.05) with weaning weight and 0.62 (0.05) with coronet circumference at 3 months. Conclusions Coronet measurements could be used in genetic evaluation as a proxy for birth weight. However, the most useful coronet measure was when it was recorded at birth. This would still require catching the calf at birth, thus greatly reducing the benefit of having an alternative measure. Coronet circumference recorded in the branding cradle at 3 months of age was also a useful predictor of birth weight but added little if post-birth weights were available. Importantly, all post-birth indirect measures of birth weight require adjustment for animal age and, therefore, would need recording of the individual calf’s date of birth. Implications Coronet circumference recorded at birth and 3 months of age does not appear to be a suitable proxy for genetic evaluation of birth weight.

Effects of use of conventional and sexed semen on conception rate, calf sex, calf birth weight, and stillbirth in Holstein heifers

Pregnancy rate is low in artificial insemination with sexed semen compared to conventional semen. This situation poses a major problem for dairy farms. The aim of this study was to determine the effects of semen type on conception rate, calf sex and birth weight, stillbirth, pregnancy loss, and postpartum maternal body weight (MBW) in Holstein heifers inseminated with sexed (n = 229), and conventional semen (n = 153). The female and male calf ratios of the heifers inseminated with sexed and conventional semen were found to be 88% to 54.8% and 12% to 45.2%, respectively. There was a significant difference between sperm type and calf sex (p < 0.001). While 36.7% of calves between 34 and 36 kg birth weights were born from heifers inseminated with sexed semen, 15.7% were born from heifers inseminated with conventional semen. Moreover, 46% and 17.3% of calves that had birth weights of 36.1-38.1 kg and > 38.2 kg were born from heifers inseminated with sexed semen while 40% and 44.3% were born from heifers inseminated with conventional semen, respectively. A statistically significant relationship was found between semen type and calf birth weights (p < 0.001). After calving, there was a significant difference between semen type and MBW after calving (p < 0.001). In the sexed and conventional semen groups, the MBW after calving was found to range from 11.3% to 23.5% in the 400-460 kg, 46.7% to 57.4% in the 461-511 kg, and 42% to 19.1% in the 512-587 kg weight categories, respectively. There was no statistically significant difference (p > 0.05) between sperm type and mean gestation length and calf birth weight, pregnancy loss, stillbirth rate, and weaning calf mortality rates. There was a strong positive correlation between semen type, sex, and calf birth weight. Furthermore, there was a significant correlation between the MBW, the gestation period and the survival status of the calves. It was determined that there was a minor positive relationship between the insemination season and the gestation period, MBW, and the survival status of the calves. Our results demonstrated that with careful and consistent application of herd management program in dairy cattle farms, the rates of pregnancy obtained with sexed and conventional semen will increase, whilst parameters such as stillbirth and pregnancy loss will decrease.

PUFA supplements to improve diarrhea, fecal consistency, and disease resilience in neonatal and preweaning calves

The flaxseed oil (FSO) rich in polyunsaturated fatty acids (PUFA) were supplemented orally to ten male and female neonatal calves from day 6 of birth to day 28 to improve resilience to disease incidences (TG) and compared to calves reared without PUFA supplement (CG). The PUFA supplementation in liquid form was discontinued on day 29 and fed as bolus consisting of 25 g of ground flaxseed and 25 g of jaggery until day 90. The total dry matter intake in cluding milk solids in neonata calves was 400 g in CG and 428 g in TG (P=0.38). Digestible DMI, CP and energy intake in male and female calves of TGs was significantly (P&lt; 0.05) higher the CG. However, the body weight gain in calves during neonatal (P=0.08) and preweaning (P=0.14) age was comparable between groups. The serum IgG were 30 mg/mL on day 2 but higher in calves in TGs on day 7 (P=0.08) and day 14 (P=0.07)after birth but comparable in subsequent period until day 30 after birth. Calves resilience to diarrhea, pyrexia, anorexia, skin infection, profused lacrimation, navel ill, muzzle keratinization, umbilical hernia, fecal consistency (FC), and egg count (FEC) were examined. PUFA supplementation reduced the disease risk rate in TG by 42% (P&lt; 0.001) and diarrhea by three folds compared to CG. Haemoglobin, erythrocytes, and lymphocytes improved significantly from day 30 after birth. The intervention was recommended to reduce calf mortality and imrpoved health and body weight gain during neonatal and preweaning age.

Association of a variant upstream of growth differentiation factor 11 (GDF11) on carcass traits in crossbred beef cattle.

The mature peptide of growth differentiation factor 11 (GDF11) in Bos taurus breeds, shares 90% amino acid sequence similarity to myostatin (MSTN), where loss-of-function mutations result in muscular hyperplasia causing a phenotype known as double-muscling. Mutations in the MSTN coding sequence increase muscle mass and reduce fat and bone tissues, but also confer poor fertility, reduced stress tolerance, and increased calf mortality. GDF11 influences skeletal muscle development in mice, and muscular atrophy can be induced by exogenous GDF11 treatment. To date, there are no reports of GDF11's role in bovine carcass traits. To determine associations between GDF11 and carcass quality in beef cattle, bovine GDF11 was examined in crossbred Canadian beef cattle populations during finishing. Few coding variants were found in this functionally important gene, but an upstream variant c.1-1951C > T (rs136619751) with a minor allele frequency of 0.31 was identified and further genotyped in two separate populations of crossbred steers (n = 415 and 450). CC animals had lower backfat thickness, marbling percentage, and yield score than CT or TT animals (P < 0.001 and < 0.05). These data suggest a role of GDF11 in carcass quality in beef cattle and may provide a selection tool to improve carcass traits in cattle.

Detailed analysis of mortality rates in the female progeny of 1,001 Holstein bulls allows the discovery of new dominant genetic defects.

Reducing juvenile mortality in cattle is important for both economic and animal welfare reasons. Previous studies have revealed a large variability in mortality rates between breeds and sire progeny groups, with some extreme cases due to dominant mutations causing various syndromes among the descendants of mosaic bulls. The purpose of this study was to monitor sire-family calf mortality within the French and Walloon Holstein populations, and to use this information to detect genetic defects that might have been overlooked by lack of specific symptoms. In a population of heifers born from 1,001 bulls between 2017 and 2020, the average sire-family mortality rates were of 11.8% from birth to 1 year of age and of 4.2, 2.9, 3.1, and 3.2% for the perinatal, postnatal, preweaning, and postweaning subperiods, respectively. After outlining the 5 worst bulls per category, we paid particular attention to the bulls Mo and Pa, because they were half-brothers. Using a battery of approaches, including necropsies, karyotyping, genetic mapping, and whole-genome sequencing, we described 2 new independent genetic defects in their progeny and their molecular etiology. Mo was found to carry a de novo reciprocal translocation between chromosomes BTA26 and BTA29, leading to increased embryonic and juvenile mortality because of aneuploidy. Clinical examination of 2 calves that were monosomic for a large proportion of BTA29, including an orthologous segment deleted in human Jacobsen syndrome, revealed symptoms shared between species. In contrast, Pa was found to be mosaic for a dominant de novo nonsense mutation of GATA 6 binding protein (GATA6), causing severe cardiac malformations. In conclusion, our results highlight the power of monitoring juvenile mortality to identify dominant genetic defects due to de novo mutation events.

EVALUATION OF BACTERIAL INVOLVEMENT IN AN EPISODE OF NEONATAL CALF DIARRHEA

Diarrhea and digestive disorders represent one of the leading causes of mortality in calves during the first days of life. This study aimed to establish the level of antibiotic resistance of the flora identified in calves with digestive problems and also in their environment. Bălțată Românească calves aged up to three weeks, showing an increased morbidity/mortality from a farm in Brașov county, as well as their habitat were sampled. Eight antimicrobials used in ruminants and on this specific farm (penicillin, streptomycin, amoxicillin, gentamicin, oxytetracycline, tulathromycin, cefaclor, trimethoprim/ sulfamethoxazole) were tested for their efficacy against the bacterial isolates. The samples were subjected to standard microbiological examinations; subsequently, strains such as Escherichia fergusoni, Escherichia hermannii, Shigella dysenteriae, Proteus penneri, Morganella morganii ssp. siboni, Escherichia coli, Escherichia vulneris, with potentially high pathogenicity were identified. The highest antibacterial efficacy was observed with gentamicin. The MAR (multiple antibiotic resistance) index exceeded the value of 0.2 for each of the tested strains, indicating a high level of antibiotic resistance of the isolated bacterial population, thus supporting the inducive role of isolated species in the clinical episodes.

Dry Period Length in Dairy Cattle: II. Influence on Calf Survival and Growth Performance

This study was conducted to investigate the effects of dry period length (DPL) on survival rate, gender, growth performance, mortality of Holstein calves. Data belonged to 800 Holstein cows in different parities (2nd, 3rd and ≥4th) and 800 calves delivered by these cows. DPL were classified in 5 categories (≤40, 41-50, 51-60, 61-70, ≥71 days). Calves were weighed and body dimensions (body length, wither height, hearth girth) at birth and 6th months of age. There were significant relationships between DPL and calf gender (P

Isolation of common Calves diarrhea 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 &gt; 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.

Epidemiological, clinico-diagnostic and therapeutic aspects of bovine respiratory disease in Indian buffaloes

Bovine Respiratory Disease (BRD) is major health problem occurring worldwide in bovines, responsible for high morbidity and mortality in calves and heavy economic losses in terms of production losses in milch animals and cost of veterinary treatment. Hence the present study was planned to investigate epidemiological, clinico-diagnostic and therapeutic aspects of BRD in Indian buffaloes. A total of 805 buffaloes reported to TVCC, COVAS, Udgir during the study period were screened for Bovine respiratory disease. On the basis of history of varying degree of nasal discharge, coughing, dyspnoea and abnormal lung sounds, 37 buffaloes were found positive for BRD, indicating 4.60% overall prevalence. The haemoanalysis showed significant (P&lt;0.01) leukocytosis associated with neutrophilia. The radiographic examination of thorax revealed variable degree of congestion and diffuse consolidation of lungs. The bacteria isolated from nasal swabs were Staphylococcus sp., Streptococcus sp., E. coli, Corynebacterium sp., Klebsiella sp., Manheimia haemolytica, Brevundimonas sp. and Pseudomonas sp. Antibiogram of pure culture organisms isolated from BRD affected buffaloes revealed highest sensitivity for gentamicin (83.33%), followed by enrofloxacin (58.33%), ceftiofur sodium (50.00%), moxifloxacin (33.33%). Thirty-one BRD affected buffaloes were randomly distributed in four groups and treated with gentamicin 4 mg/ kg, enrofloxacin 5 mg/kg, moxifloxacin 5 mg/kg and ceftiofur 1.6 mg/kg respectively. All treated buffaloes from different groups clinically cured within 5 to 15 days. Based on results of current therapeutic trial, gentamicin proved most effective and economic in treatment of BRD in buffaloes.

Development of an Aggressive Treatment Protocol against Neonatal Calf Diarrhea: The Last Chance to Rescue Severely Infected Calves

Despite many efforts to control and treat neonatal calf diarrhea (NCD), it remains the primary cause of calf mortality in dairy herds worldwide. The objective of this article was to develop and discuss an empirical therapeutic protocol to save newborn calves with severe diarrhea. The pathophysiology of diarrhea has been well described previously. However, there is a significant gap between scientific findings and practical implementations. Reducing the number of calves with failure of passive transfer, regular sanitation of the calf environment, and optimal dry cow nutrition and management are fundamental measures in controlling diarrhea in commercial settings. As such, optimizing colostrum feeding management and improving ambiance hygiene are among the most important management practices to prevent calf diarrhea. Nonetheless, the occurrence of NCD would be unavoidable due to its multifactorial nature and pathophysiology. According to the degree of dehydration and general appearance of ill calves (e.g., degree of sunken eye and loss of suck reflex), NCD can be classified into mild to severe cases. Early diagnosis and treatment of both mild and severe cases could reduce pathogens shedding into the calf environment. Notably, diarrhea treatment needs profound scientific farm education and mentoring regarding the physiology of NCD. Since a variety of organisms, such as bacteria, viruses, and protozoa, may be responsible for NCD, it is evident that reliable diagnosis requires optimal sampling and laboratory analysis. However, waiting for laboratory results may waste the golden time of treatment. Therefore, rapid and decisive treatment would be mandatory, especially in severely infected calves or sepsis cases. Accordingly, an effective aggressive treatment protocol was developed and discussed in this article as the last chance to keep diarrheic calves alive.

Stochastic, individual animal systems simulation model of beef cow-calf production: development and validation.

A stochastic, individual animal systems simulation model describing U.S. beef cow-calf production was developed and parameterized to match typical U.S. Angus genetics under cow-calf production conditions in the Kansas Flint Hills. Model simulation results were compared to available actual, multivariate U.S. cow-calf production data reported according to beef cow-calf standardized performance analysis (SPA) methodology through North Dakota State University's CHAPS program to assess model validity. Individual animal nutrition, reproduction, growth, and health characteristics, as well as production state are determined on a daily time step. Any number of days can be simulated. These capabilities allow for decision analysis and assessment of long-run outcomes of various genetic, management, and economic scenarios regarding multiple metrics simultaneously. Parameterizing the model to match Kansas Flint Hills production conditions for the years 1995 through 2018, 32 different genetic combinations for mature cow weight and peak lactation potential were simulated with 100 iterations each. Sire mature cow weight genetics ranged from 454 to 771 kg in 45 to 46 kg increments. Sire peak lactation genetics were considered at 6.8, 9, 11.3, and 13.6 kg/d for all eight mature cow weights. Utilizing model results for the years 2000 to 2018, raw model results were assessed against actual historical cow-calf production data. Exploratory factor analysis was applied to interpret the underlying factor scores of model output relative to actual cow-calf production data. Comparing modeled herd output with CHAPS herd data, median average calf weaning age, average cow age, percent pregnant per cow exposed, and percent calf mortality per calf born of model output was 3.4 d greater, 0.2 yr greater, 1 percentage point less, and 1.7 percentage points greater, respectively. Subtracting the median CHAPS pre-weaning average daily gain from the median modeled pre-weaning average daily gain for each of the eight respective mature cow weight genetics categories, and then calculating the median of the eight values, the median difference was -0.21 kg/d. Performing the same calculation for birth weight and adjusted 205 d weaning weight, the modeled data was 4.9 and 48.6 kg lighter than the CHAPS data, respectively. Management and genetic details underlying the CHAPS data were unknown.

Evaluating the effectiveness of colostrum as a therapy for diarrhea in preweaned calves.

Diarrhea is the primary cause of morbidity and mortality in dairy calves. Many cases of diarrhea in calves are treated with antimicrobials, increasing the risk of antimicrobial resistance, therefore, creating a need for alternative therapies. The objective of this study was to evaluate the effects of feeding spray-dried maternal derived bovine colostrum replacer at the onset of diarrhea on calf growth and duration and severity of the disease in preweaning dairy calves. At a calf-raising facility in southern Ontario, calves were scored for fecal consistency twice daily on a scale of 0 to 3 and enrolled into the trial when they had 2 consecutive fecal scores of 2 (runny or spreads readily) or one fecal score of 3 (liquid consistency, splatters). Calves were then randomly allocated to receive one of the following 3 treatments: (1) control (CON; n = 35): 8 feedings over 4 d of 2.5 L of milk replacer at a concentration of 130 g/L (26% crude protein and 17% fat); (2) short-term colostrum supplementation (STC; n = 35): 4 feedings over the first 2 d of 2.5 L of a mixture of milk replacer at 65 g/L and bovine colostrum replacer at 65 g/L (26% IgG and 14.5% fat) followed by 4 feedings over 2 d of 2.5 L of milk replacer at a concentration of 130 g/L; or (3) long-term colostrum supplementation (LTC; n = 38): 8 feedings over 4 d of 2.5 L of a mixture of milk replacer at 65 g/L and bovine colostrum replacer at 65 g/L. Serum IgG was determined at arrival to the facility and body weight, days to enrollment since facility arrival, and severity of diarrhea were recorded at enrollment. Daily health exams evaluating fecal consistency were performed for 28 consecutive days after enrollment and body weight was measured at d 0, 1, 2, 3, 4, 7, 14, 21, 28, 42 and 56 after enrollment. The median days to resolution of a case of diarrhea was 3.5 d (range: 0.5-11.5 d), 2.75 d (range: 0.5-11.0 d), and 2.75 d (range: 0.5-7.0 d) in CON, STC, and LTC, respectively. Using a Cox proportional hazards model, it was found that calves in LTC group had faster resolution of diarrhea compared with calves in the CON group. In addition, there was an association between both days to enrollment since facility arrival and body weight and resolution of diarrhea, where calves who were at the facility longer before enrollment and heavier at the onset of diarrhea, resolved diarrhea quicker. In addition, calves with a fecal score of 3 at enrollment took longer to resolve their case of diarrhea. With respect to body weight, a linear regression model was built and found that over the 56 d following enrollment calves in the LTC treatment grew 98 g/d more than calves in the CON group. These results suggest that bovine colostrum may be an effective therapy for diarrhea in preweaning calves.

Some factors associated with mortality rate of Friesian calves during first year of age in Egypt

Some factors associated with mortality rate of Friesian calves during first year of age in Egypt

Reduction in Mortality of Calves with Bovine Respiratory Disease in Detection with Influenza C and D Virus

Both influenza C (ICV) and influenza D (IDV) viruses were recently included as bovine respiratory disease (BRD) causes, but their role in BRD has not been evaluated. Therefore, the mortality and reproductive performances of BRD calves with different isolated viruses were determined in this study. Data on 152 BRD calves with bovine viral diarrhoea virus (BVDV), bovine respiratory syncytial virus (BRSV), bovine coronavirus (BCoV), bovine parainfluenza virus 3 (BPIV-3), ICV, or IDV from nasal swab samples using real-time rt-PCR were used. The general data and respiratory signs were recorded immediately, and thereafter, the data on dead or culling calves due to BRD and reproductive performance were collected. The percentages of the BRD calves were 71.7%, 52.6%, 40.8%, 10.5%, 68.4%, and 65.8% for BVDV, BRSV, BCoV, BPIV-3, ICV, and IDV, respectively. Mucous secretion (OR = 4.27) and age ≤ 6 months (OR =14.97) had higher risks of mortality than those with serous secretion and older age. The calves with IDV had lower risks of culling than those without IDV (OR = 0.19). This study shows that most viral infections in BRD calves are a combination of viruses with BVDV, ICV, and IDV. In addition, IDV might have a role in reducing the severity of BRD calves.