Replacing Inorganic Source of Zinc with Zinc Hydroxy Chloride: Effects on Health Status, Hemato-biochemical Attributes, Antioxidant Status, and Immune Responses in Pre-ruminant Crossbred Calves.

The current research aimed to assess the feasibility of using Zn hydroxy chloride (ZnOHCl) as an alternative to ZnSO4 in pre-ruminant crossbred calves. Twenty-four male crossbred calves (Tharparkar × Holstein Friesian) were categorized into four groups according to body weight and age (body weight 31 kg; age 10 days). Experimental calves were kept on a similar feeding regimen except that different groups were supplemented with either 0 mg Zn/kg DMI (Zn-0), 80 mg Zn/kg DMI as ZnSO4 (ZnS-80), 40 mg Zn/kg DMI as ZnOHCl (ZnH-40), or 80 mg Zn/kg DMI as ZnOHCl (ZnH-80). All the calves were fed for 90 days as per ICAR (2013) feeding standard to fulfill their nutrient requirements for growth rate of 500 g/day. The study observed the influence of different sources and varying levels of Zn supplementation over a 90-day experimental period on health status, hemato-biochemical attributes, antioxidant status, immune responses, and plasma minerals and erythrocyte Zn concentrations. The data was examined using a randomized complete block design (RCBD) with fixed effects of treatment, period, and their interaction. The results indicated that irrespective of the sources and levels of Zn, supplementation did not lead to significant changes in health status as assessed by fecal score, nasal score, ear score, and eye score. Hematological parameters remained unchanged following supplementation with different sources and levels of Zn. Zn-supplemented groups showed higher levels of total protein, globulin, and alkaline phosphates (ALP) compared to the non-supplemented group. However, no significant variations were detected within the Zn-supplemented groups. Zinc supplementation significantly increased total antioxidant capacity (TAC), antioxidant enzyme activity, total immunoglobulin (Ig), immunoglobulin G (IgG), cell-mediated immunity (CMI), and humoral immunity (HI); however, no significant variations were detected among Zn-supplemented groups. Zn supplementation enhanced plasma and RBC Zn concentration without affecting the plasma concentration of other minerals. However, among the Zn-supplemented groups, 80 mg Zn/kg DMI as ZnOHCl resulted in the highest RBC Zn concentration. The study results demonstrate that Zn supplementation enhanced biomarkers of zinc status, antioxidant levels, and immune responses in pre-ruminant crossbred calves. Nevertheless, no significant variations were observed between the different Zn sources (ZnSO4 and ZnOHCl) utilized in this study. Research suggests that ZnOHCl could be a feasible alternative to ZnSO4 in the diet of pre-ruminant crossbred calves.

Evaluation of candidate data-based welfare indicators for veal calves in Switzerland.

Welfare assessment protocols have been developed for dairy cows and veal calves during the past decades. One practical use of such protocols may be conducting welfare assessments by using routinely collected digital data (i.e., data-based assessment). This approach can allow for continuous monitoring of animal welfare in a large number of farms. It recognises changes in the animal welfare status over time and enables comparison between farms. Since no comprehensive data-based assessment for veal calves is currently available, the purposes of this review are (i) to provide an overview of single existing data-based indicators for veal calves and (ii) to work out the necessary requirements for data-based indicators to be used in a comprehensive welfare assessment for veal calves in Switzerland. We used the Welfare Quality Protocol® (WQ) for veal calves and the Terrestrial Animal Health Code from the World Organisation of Animal Health for guidance throughout this process. Subsequently, routinely collected data were evaluated as data sources for welfare assessment in Swiss veal operations. The four WQ principles reflecting animal welfare, i.e., 'good feeding', 'good housing', 'good health' and 'appropriate behaviour' were scarcely reflected in routinely available data. Animal health, as one element of animal welfare, could be partially assessed using data-based indicators through evaluation of mortality, treatments, and carcass traits. No data-based indicators reflecting feeding, housing and animal behaviour were available. Thus, it is not possible to assess welfare in its multidimensionality using routinely collected digital data in Swiss veal calves to date. A major underlying difficulty is to differentiate between veal calves and other youngstock using routine data, since an identifying category for veal calves is missing in official Swiss databases. In order to infer animal welfare from routine data, adaptations of data collection strategies and animal identification are required. Data-based welfare assessment could then be used to complement on-farm assessments efficiently and, e.g., to attribute financial incentives for specifically high welfare standards accordingly.

Study of Akabane disease in an Iranian dairy herd: a re-emerging disease.

Akabane virus is a teratogenic pathogen transmitted by Culicoides spp. to ruminants. The virus induces anomalies in the central nervous system in the developing fetus, resulting in arthrogryposis-hydranencephaly (A-H) syndrome. During three outbreaks of the disease (2002, 2013, and 2020), 77 calves were born in Varamin, Iran, with A-H syndrome. The presenting neurologic signs were categorized into three main groups, as common, less common, and uncommon signs. The common signs were unawareness of the surroundings, blindness, deep depression, partial failure of suckling, and unintelligent behavior. The less commonly noted signs were hyperexcitability, regurgitation, head pressing, compulsive walking, and kicking, while the uncommon signs comprised protrusion of the tongue, making sounds resembling barking, carnivore-like milk drinking, and deafness. Arthrogryposis, dome-shaped skull, kyphosis, torticollis, lordosis, scoliosis, and spina bifida were the diagnosed skeletal defects. Upon necropsy, hydranencephaly, hydrocephaly, and microencephaly were seen in the calves presenting neurologic signs, while astrocytosis, astrogliosis, focal gliosis, perivascular, perineuronal, and submeningeal edema, perivascular cuffing, non-suppurative meningitis, non-suppurative encephalitis and lymphoplasmacytic infiltration, and perivascular and parenchymal hemorrhage were seen in samples obtained from the brains. RT-PCR detected Akabane virus in the brain tissues of the affected calves. This is the first clinical study of Akabane disease in calves in Iran.

Dexamethasone administration restored growth in dairy calves exposed to heat stress.

Recent evidence indicates that the heat stress loss on the growth performance of calves is associated with the diversion of nutrients to control enteritis and systemic inflammation. In this study, we investigated the impact of heat stress on markers of inflammation, feed use-efficiency, and growth of dairy calves. We hypothesized that dexamethasone, which is known for its immunosuppressive and anti-inflammatory properties, would reduce inflammation and restore the growth of calves exposed to heat stress. Thirty-two Holstein bull calves (body weight (BW) 68.5 ± 1.37 kg; age 3.5 ± 0.5-week-old; mean ± SD) were housed in individual pens in climate-controlled rooms at constant ambient temperature and allowed to adjust to facilities for 5 d before the start of treatments. Calves were randomly assigned to one of 4 treatments (n = 8/treatment) in a 2 × 2 factorial arrangement of environment (ENV, thermoneutral or heat stress) and intervention (INT, saline or dexamethasone) imposed for 5 d as follow: 1) thermoneutral (constant ambient temperature of 20°C 24 h/d) and administration of saline, 2) thermoneutral (constant ambient temperature of 20°C 24 h/d) and administration of dexamethasone, 3) cyclic heat stress (40°C ambient temperature, from 0800 to 1900 h/d) and administration of saline, 4) cyclic heat stress (40°C ambient temperature, from 0800 to 1900 h/d) and administration of dexamethasone. Dexamethasone (0.05 mg/kg BW), or saline (1.2 mL) was administered intramuscularly on d 1 and 3. Upon completion of treatments, calves were euthanized on d 5 to obtain jejunum mucosa samples. Commercial milk replacer, starter grain, and water were offered, and intake was monitored daily. Rectal temperature and respiratory rate were monitored 3 times daily. Blood samples were collected on d 1, 3, and 5 to determine serum pro-inflammatory cytokine concentrations. A section of the jejunum was collected and snap-frozen to determine the concentration of pro-inflammatory markers. Statistical analyses included a mixed model, fixed effects of ENV, INT, consecutive measurements taken over time (d, h, or both), replica, and random effects of calf and error (SAS version 9.4, SAS Institute Inc., Cary, NC). The measurements collected immediately before treatment allocation were included as covariates in the model. An ENV effect showed that heat stress increased rectal temperature (38.72 vs. 39.21°C), respiratory rate (36 vs. 108 breaths/min), and water intake (3.2 vs. 6.6 L/d). The treatments did not affect dry matter intake. An ENV × INT interaction showed that heat stress with saline decreased average daily gain (ADG) by 35% and tended to decrease feed use-efficiency by 36%, but the use of dexamethasone to treat heat stress restored ADG and feed use-efficiency comparable to their basal levels. An ENV × INT interaction revealed that heat stress with saline increased jejunal interleukin (IL)-6 concentration 2-fold, but dexamethasone treatment of heat stress restored jejunal IL-6 concentration to basal levels. The bioenergetic cost of the heat stress-immune pro-inflammatory response ranged between 1.18 and 1.50 Mcal of ME. Overall, the administration of dexamethasone reduced the jejunal concentration of a pro-inflammatory marker and restored the heat stress-associated reduction in growth and feed use-efficiency. The immunomodulation and anti-inflammatory effects of dexamethasone could be part of a homeorhetic change that results in a shift from maintenance functions to support growth on calves exposed to heat stress.

Impact of Parenteral Maternal Supplementation with Trace Minerals and Vitamins on Neonatal Calf Antioxidant System and Growth in a Dairy Herd.

Oxidative stress may affect new born calves due to high stress suffered around birth. We hypothesized that maternal supplementation with micronutrients and vitamins in late gestation enhance the neonatal calf's antioxidant system, decreasing the occurrence and duration of diarrhea, and improving growth from birth through weaning. To test this hypothesis, 80 multiparous cows were cluster-assigned to treatment groups. Treated group (TG) cows received mineral and vitamin supplementation while control group (CG) cows received saline solution. Feed intake and fecal score were measured daily until the ninth week. Weight and body measurements were registered weekly, and blood samples were collected from postpartum cows and calves after birth and at 7, 14, and 63 days of life. Although CG calves had greater fecal scores (p = 0.01), diarrhea characteristics did not differ. Calves in the TG showed greater starter intake (p = 0.04). Feed efficiency showed a trend with treatment-age interaction (p = 0.06). Calves in the CG had wider hips in the first week (p = 0.03), but not by the ninth week. Total antioxidant status, thiobarbituric acid reactive substances, and haptoglobin did not differ between treatment groups. Serum metabolites showed no differences. Supplementation did not impact calf antioxidant system or growth in the first two months.

Cryptosporidium spp. Infection and Genotype Identification in Pre-Weaned and Post-Weaned Calves in Yunnan Province, China.

BACKGROUND: Cryptosporidium is a globally distributed zoonotic protozoan parasite in humans and animals. Infection is widespread in dairy cattle, especially in calves, resulting in neonatal enteritis, production losses and high mortality. However, the occurrence of Cryptosporidium spp. in pre- and post-weaned calves in Yunnan Province remains unclear. METHODS: We collected 498 fecal samples from Holstein calves on 10 different farms in four regions of Yunnan Province. Nested PCR and DNA sequencing were used to determine the infection, species and genotypes of Cryptosporidium spp. in these animals. RESULTS: The overall occurrence of Cryptosporidium spp. in Holstein calves was 32.9% (164/498), and the prevalence in pre- and post-weaned calves was 33.5% (106/316) and 31.9% (58/182), respectively. Four Cryptosporidium species were identified in these animals, namely C. bovis (n = 119), C. parvum (n = 23), C. ryanae (n = 20) and C. andersoni (n = 2). Based on sequencing analysis of the 60 kDa glycoprotein gene of C. bovis, C. parvum and C. ryanae, six subtypes of C. bovis (XXVIe, XXVIb, XXVIf, XXVIa XXVIc and XXVId), two subtypes of C. parvum (IIdA19G1 and IIdA18G1) and four subtypes of C. ryanae (XXIf, XXId, XXIe and XXIg) were identified. CONCLUSIONS: These results provide essential information to understand the infection rate, species diversity and genetic structure of Cryptosporidium spp. populations in Holstein pre-weaned and post-weaned calves in Yunnan Province. Further, the presence of IIdA18G1 and IIdA19G1 in C. parvum implies significant animal and public health concerns, which requires greater attention and more preventive measures.

Association of Bovine Respiratory Disease during the Pre-Weaning Period with Blood Cell Counts and Circulating Concentration of Metabolites, Minerals, and Acute Phase Proteins in Dairy Calves Transported to a Calf Raising Facility.

Our objective was to investigate the association of bovine respiratory disease (BRD) occurring within the first 56 days of life with blood cell counts and the circulating concentration of metabolites, minerals, and acute phase proteins throughout the pre-weaning period in dairy calves transported to a heifer raising facility within their first week of life. Data from 305 calves transported from dairies in Minnesota to a calf raising facility in New Mexico within their first four days of life were used in this retrospective cohort study. Blood samples were collected at 7, 17, 34, and 56 days of life for the analysis of blood cell counts, biochemistry, and the concentration of acute phase proteins. Blood urea nitrogen, albumin, GLDH, CK, P, Na, K, Cl, Zn, Hp, SAA, and monocyte counts were associated with BRD status throughout or at least at one of the time points evaluated in this study. In conclusion, several hematological variables were associated with BRD status in dairy calves that underwent transportation stress in early life.

Cryptosporidium Infections in Neonatal Calves on a Dairy Farm.

This study was conducted with the aim of the molecular identification of the protozoan parasite Cryptosporidium spp. in calves in the early stage of their development on a dairy farm in Eastern Slovakia. Twenty-five Holstein and Holstein cross calves were included in the study and monitored from their birth to the fifth week of life (1-5 weeks). Fresh fecal samples were collected from the same group of calves each week, except during the fourth week, and with the exception of Sample 8. All samples were analyzed using the Ziehl-Neelsen staining method and coproantigen was tested using the ELISA test as the screening method. Using the ELISA method, the highest incidence of cryptosporidiosis was observed in the second week of life of the calves, while the antigen was detected in 21 (91.6%) calves. Using the Ziehl-Neelsen staining method, the highest incidence was also observed in the second week, with an incidence rate of 62.5%. Positive isolates confirmed by the ELISA test were molecularly characterized. The species and subtypes of Cryptosporidium in the positive isolates were identified using PCR and the sequence analysis of the small subunit of the ribosomal 18S RNA (ssu rRNA) and the 60 kDa glycoprotein (gp60) genes of the parasite. The sequence analysis of 29 isolates at the 18S rRNA loci confirmed the presence of two species-Cryptosporidium parvum and Cryptosporidium ryanae. Out of 29 isolates, 25 were assigned to the species C. parvum, with the gp60 locus identified as genotype IIaA17G1R1. Among the individual animal groups, calves are the most common reservoirs of the C. parvum zoonotic species. This disease has significant public health implications as contact with livestock and their feces and working with barn manure are major sources of infection, not only for other animals but also for humans.

Predicting Body Weight in Pre-Weaned Holstein-Friesian Calves Using Morphometric Measurements.

Regularly weighing calves helps to assess the efficiency of the rearing period and contributes to animal welfare by allowing more precise feeding and medication application in dairy farming, but many farmers do not weigh their calves regularly. Improving the feasibility of this process is, therefore, important. The use of morphometric measurements has been used to estimate the weight of cattle. However, many studies have focused on adult animals or used a wide age range. As calves experience allometric tissue growth, specific models for certain ranges might be more accurate. Therefore, the aim of this work was to develop a weight estimation model specific for pre-weaned Holstein-Friesian calves using morphometric measurements and to compare the model with another equation previously validated for the same breed with young and adult animals. From four dairy farms, 237 measurements of body weight, heart girth, abdominal girth, hip height, withers height, and body length were taken from Holstein-Friesian male and female calves. Linear and non-linear regression analysis was used to test the relationship between body weight and morphometric measurements, with age, sex, and farm as possible explanatory variables. Selected models were compared with goodness of fit and agreement tests. The final model was able to accurately predict body weight (R2 = 0.96) with a mean difference of -1.4 ± 3.24 kg. Differences in the relationship between body weight and morphometric traits were observed between farms, but not between males and females. The genetics of the animal population at farm level may be responsible for this variability and further studies are needed to understand this variability and improve weight prediction models. The developed model was able to perform better in the agreement tests than the previously validated model for Holstein-Friesian animals, suggesting that different equations should be used depending on the growth phase the animal is in. In addition, a web application has been developed to facilitate the use of the developed model by farmers. This avoids the use of calibrated weight bands, which are usually calibrated for a broader age range or for beef cattle.

Summer scour syndrome in weaned dairy calves: case series.

BACKGROUND: Summer scour syndrome (SSS) is a recently identified pathological condition affecting weaned dairy and dairy-beef calves during their first grazing season in Ireland. The syndrome is characterised by diarrhoea, weight loss, weakness, and can ultimately lead to death in some calves. Oral and oesophageal ulcerations are present in some cases. This study aimed to characterise a series of SSS cases in weaned dairy-bred calves on Irish commercial farms. RESULTS: Five farms with calves having unexplained diarrhoea at grass were referred by private veterinary practitioners (PVP) following preliminary testing to exclude coccidiosis and parasitic gastroenteritis. Farms were visited within 2 to 5 days following PVP's referrals, or 2 days to 3 weeks relative to the onset of clinical signs. Farm management data, grass and concentrate samples, and biological samples from 46 calves (8 to 10 calves/farm) displaying clinical signs were collected. Two farms were subsequently found positive for coccidiosis and/or had chronic pneumonia problems after a thorough herd investigation and were designated as non-case farms (NCF). The remaining three farms were deemed typical SSS outbreaks (case farms; CF). Mean rumen fluid pH per farm ranged from 6.67 to 7.09 on CF, and 6.43-6.88 on NCF. Mean rumen fluid ammonia concentrations ranged from 17.6 to 29.6 mg/L and 17.2-45.0 mg/L on CF and NCF, respectively. Corresponding blood ammonia concentrations ranged from 129 to 223 µmol/L and 22-25 µmol/L. Mean blood copper and molybdenum concentrations were within normal range on all farms. Grass crude protein concentrations on the paddocks where the calves had grazed, and were currently grazing on the day of visit ranged from 137 to 148 g/kg DM and 106-177 g/kg DM, respectively on CF, and 160-200 g/kg DM and 151-186 g/kg DM, respectively on NCF. On CF, inorganic nitrogen fertiliser was applied 1 to 3 weeks pre-grazing, whereas on the two NCF, inorganic nitrogen fertiliser was applied 2 to 3 weeks pre-grazing on one farm and no fertiliser was applied on the other. CONCLUSION: These findings suggest that copper or molybdenum toxicity, and ruminal acidosis are not the primary causes of SSS. High blood ammonia concentrations and the timing and level of inorganic nitrogen fertiliser application to paddocks pre-grazing, warrant further investigation.

Rumen and hindgut microbiome regulate average daily gain of preweaning Holstein heifer calves in different ways.

BACKGROUND: The average daily gain (ADG) of preweaning calves significantly influences their adult productivity and reproductive performance. Gastrointestinal microbes are known to exert an impact on host phenotypes, including ADG. The aim of this study was to investigate the mechanisms by which gastrointestinal microbiome regulate ADG in preweaning calves and to further validate them by isolating ADG-associated rumen microbes in vitro. RESULTS: Sixteen Holstein heifer calves were selected from a cohort with 106 calves and divided into higher ADG (HADG; n = 8) and lower ADG (LADG; n = 8) groups. On the day of weaning, samples of rumen contents, hindgut contents, and plasma were collected for rumen metagenomics, rumen metabolomics, hindgut metagenomics, hindgut metabolomics, and plasma metabolomics analyses. Subsequently, rumen contents of preweaning Holstein heifer calves from the same dairy farm were collected to isolate ADG-associated rumen microbes. The results showed that the rumen microbes, including Pyramidobacter sp. C12-8, Pyramidobacter sp. CG50-2, Pyramidobacter porci, unclassified_g_Pyramidobacter, Pyramidobacter piscolens, and Acidaminococcus fermentans, were enriched in the rumen of HADG calves (LDA > 2, P < 0.05). Enrichment of these microbes in HADG calves' rumen promoted carbohydrate degradation and volatile fatty acid production, increasing proportion of butyrate in the rumen and ultimately contributing to higher preweaning ADG in calves (P < 0.05). The presence of active carbohydrate degradation in the rumen was further suggested by the negative correlation of the rumen microbes P. piscolens, P. sp. C12-8 and unclassified_g_Pyramidobacter with the rumen metabolites D-fructose (R < - 0.50, P < 0.05). Widespread positive correlations were observed between rumen microbes (such as P. piscolens, P. porci, and A. fermentans) and beneficial plasma metabolites (such as 1-pyrroline-5-carboxylic acid and 4-fluoro-L-phenylalanine), which were subsequently positively associated with the growth rate of HADG calves (R > 0.50, P < 0.05). We succeeded in isolating a strain of A. fermentans from the rumen contents of preweaning calves and named it Acidaminococcus fermentans P41. The in vitro cultivation revealed its capability to produce butyrate. In vitro fermentation experiments demonstrated that the addition of A. fermentans P41 significantly increased the proportion of butyrate in the rumen fluid (P < 0.05). These results further validated our findings. The relative abundance of Bifidobacterium pseudolongum in the hindgut of HADG calves was negatively correlated with hindgut 4-hydroxyglucobrassicin levels, which were positively correlated with plasma 4-hydroxyglucobrassicin levels, and plasma 4-hydroxyglucobrassicin levels were positively correlated with ADG (P < 0.05). CONCLUSIONS: This study's findings unveil that rumen and hindgut microbes play distinctive roles in regulating the preweaning ADG of Holstein heifer calves. Additionally, the successful isolation of A. fermentans P41 not only validated our findings but also provided a valuable strain resource for modulating rumen microbes in preweaning calves. Video Abstract.

Effects of dietary zinc on the gut microbiome and resistome of the gestating cow and neonatal calf.

Zinc is an essential trace element required in the diet of all species. While the effects of zinc have been studied in growing calves, little is known about the effect of zinc on the microbiota of the gestating cow or her neonatal calf. Understanding factors that shape the gut health of neonatal animals and evaluating the effect of dietary supplements in adult gestating animals is important in promoting animal health and informing feeding practices. The aims of this study were to determine the effect of dietary zinc on the microbiota and resistome of the gestating cow and calf. Gestating cows received standard (40 ppm) or high (205 ppm) dietary zinc levels from dry off to calving. Fecal samples were collected from cows upon enrollment and at calving and from neonatal calves. Fecal samples underwent 16S rRNA sequencing and a subset also underwent shotgun metagenomic sequencing. The effect of zinc supplementation on the diversity and composition of the cow and calf microbiome and resistome was assessed. Alpha and beta diversity and composition of the microbiota were significantly altered over time but not by treatment in the cows, with alpha diversity decreasing and 14 genera found at significantly higher relative abundances at calving compared to enrollment. Levels of 27 antimicrobial resistance genes significantly increased over time. Only a small number of taxa were differentially expressed at calving in treatment and control groups, including Faecalibacterium, Bacteroides, Turicibacter, and Bifidobacterium pseudolongum. No effect of the dam's treatment group was observed on the diversity or composition of the neonatal calf microbiota. The calf resistome, which was relatively rich and diverse compared to the cow, was also unaffected by the dam's treatment group. The impact of high levels of dietary zinc thus appeared to be minimal, with no observed changes in alpha or beta diversity, and few changes in the relative abundance of a small number of taxa and antimicrobial resistance genes.

Interpretation of the effects of rumen acidosis on the gut microbiota and serum metabolites in calves based on 16S rDNA sequencing and non-target metabolomics.

Introduction: Rumen acidosis is one of the most common diseases in beef cattle. It severely affects the normal development of calves and poses a significant threat to the farming industry. However, the influence of rumen acidosis on the gut microbiota and serum metabolites of calves is currently unclear. Objective: The aim of this study is to investigate the changes in the gut microbiota and serum metabolites in calves after rumen acidosis and analyse the correlation. Methods: Eight calves were selected as the rumen acidosis group, and eight health calves were selected as the healthy group. The faecal gut microbiota and serum metabolites of calves were detected respectively using 16S rDNA high-throughput sequencing and non-target metabolomics. The correlation between gut microbiota and serum metabolites was analyzed by Spearman correlation analysis. Results: Differential analysis of the diversity and composition of gut microbiota between eight male healthy (Health) and eight male rumen acidosis (Disease) calves revealed that rumen acidosis increased the abundance of the gut microbiota in calves. At the phylum level, compared to the Healthy group, the relative abundance of Proteobacteria in the Disease group significantly decreased (P<0.05), while the relative abundance of Desulfobacterota significantly increased in the Disease group (P<0.05). At the genus level, compared to the Disease group, the relative abundance of Alloprevotella, Muribaculaceae, Succinivibrio, Prevotella, Agathobacter and Parabacteroides significantly increased in the Healthy group (P<0.05), while the relative abundance of Christensenellaceae_R-7 and Monoglobus significantly decreased in the Healthy group (P<0.05). Differential analysis results showed the Healthy group had 23 genera with higher abundance, while the Disease group had 47 genera with higher abundance. Serum metabolomics results revealed the differential metabolites associated with rumen acidosis, including nicotinamide, niacin, L-glutamic acid and carnosine, were mainly enriched in the nicotinate and nicotinamide pathway and the histidine pathway. Conclusion: The occurrence of rumen acidosis can induce changes in the gut microbiota of calves, with a significant increase of the Christensenellaceae_R-7 genus and a significant decrease of Prevotella and Succinivibrio genera. In addition, the occurrence of rumen acidosis can also induce changes in serum metabolites including niacin, niacinamide, L-glutamine, and carnosine, which may serve as the diagnostic biomarkers of rumen acidosis of calves.

Molecular characterization and zoonotic risk assessment of Cryptosporidium spp. in children and calves in Bangladesh.

Cryptosporidium is a gastro-intestinal protozoan parasite that has been found to infect both humans and livestock. This study investigated the parasite in 998 fecal samples from Bangladeshi children (n = 299) and calves (n = 699) to determine its prevalence, genetic variation, and zoonotic importance. The nested PCR and sequencing of the SSU rRNA gene in the samples showed a Cryptosporidium infection rate of 2.3% (7/299) in children and 15.7% (110/699) in calves. Statistical analysis revealed insignificant variations in Cryptosporidium infections among children across age, gender, and study area, while in calves, the infection rate significantly differed based on location and breed. Genotyping of seven human isolates of Cryptosporidium confirmed C. hominis (n = 5) and C. parvum (n = 2). After characterizing 110 Cryptosporidium isolates from calves, C. andersoni (n = 55), C. ryanae (n = 29), C. bovis (n = 14), C. parvum (n = 10), C. ubiquitum (n = 1), and C. occultus (n = 1) were identified. Cryptosporidium hominis and C. parvum-positive samples were further subjected to nested PCR and sequencing of the glycoprotein 60 (gp60) gene for subtyping. Four C. hominis subtypes (IaA19R3, IaA23R3, IbA9G3, and IdA15G1) and one C. parvum subtype (IIdA15G1) were observed. In conclusion, Cryptosporidium was prevalent in calves but less common in children in the study locations, and the presence of zoonotic Cryptosporidium species and subtypes in calves raises concerns regarding zoonotic transmission to humans.

Effect of S. cerevisiae strain KA500 supplementation on feed performance, feed efficiency, and digestion ability in feedlot buffaloes.

Live yeasts have favorable characteristics for use in animal feed, and may become a beneficial tool to improve digestive efficiency in buffaloes (Bubalus bubalis). The productive performance, feed efficiency, and digestion ability of buffaloes fed diets supplemented with yeast (Saccharomyces cerevisiae strain KA500) were evaluated. Eighteen male Murrah buffaloes, with initial weight 250 ± 31 kg (mean ± standard deviation), and aged approximately 12 months, were randomly assigned to one of two treatments. The treatments included experimental feed containing 10 g of the live yeast capable of forming 2 × 1010 colony forming units (CFU) and control (feed with no added yeast). The daily weight gain tended to be lower (p = 0.07) in buffaloes supplemented with yeast. There was a reduction in daily dry matter intake (DMI) and in % yield of live weight in buffaloes supplemented with yeast. There was no effect of live yeast supplementation on weight gain/kg dry matter intake, height at withers or rump, body condition score, total weight gain, carcass yield, plasma urea nitrogen concentrations, purine derivatives, and plasma glucose concentrations. The digestibility of dry matter (DM) and organic matter (OM) were lower (p < 0.05) with the supplementation of live yeast, although live yeast supplementation did not affect the digestibility of neutral detergent fiber (NDF) and non-NDF OM. The strain and dosage of live yeast used did not have a positive effect on buffalo performance and digestibility of dietary nutrients.

Probiotic potential of autochthonous Lactobacillus species from buffalo calves in controlling multidrug resistant Escherichia coli.

The aim of this study was to investigate the probiotic potential of autochthonous Lactobacillus species isolated from buffalo calves against multidrug-resistant Escherichia coli. A total of 252 rectal swabs were collected from healthy neonatal buffalo calves under 30 days old from six districts of Andhra Pradesh, India in a completely randomized design from August 2019 to August 2021, of which 190 Lactobacillus strains were isolated based on cultural, morphological, biochemical and molecular tests. Out of 190 isolates, 57 showed high levels of auto-aggregation (> 80.00%) and hydrophobicity (> 60.00%) and 51 of the 57 isolates had a zone of inhibition greater than 15.00 mm in diameter against multidrug-resistant E. coli in an Agar well diffusion assay. Among the 51 isolates, 36 were found to be acid and bile tolerant and showed varying levels of sensitivity to antibiotics such as erythromycin, clindamycin, tetracycline, chloramphenicol, and ampicillin. Among the 36 isolates, Limosilactobacillus reuteri 178, L. reuteri 209, L. fermentum 182, L. fermentum 211, and Lactiplanti-bacillus plantarum 34 were non-hemolytic, and none of the isolates were able to hydrolyse gelatine. Therefore, these five autochthonous Lactobacillus species may be used in probiotic or synbiotic formulations against multidrug resistant E. coli in buffalo calves.

Beliefs, mindset and personality of farm managers working in large commercial dairy herds: Association with calf on-farm mortality.

This study aimed to describe the attitudes and personalities of farm managers (FMs) in large Estonian dairy herds and analyse the potential associations with calf mortality. The study included FMs from 114 free-stall farms with at least 100 cows. Each participant completed a questionnaire that comprised questions about the respondent and various statements to reveal their attitudes towards calves, calf mortality, and farming in general. A 7-point Likert scale was used to record the responses. The data on the number of live births and deaths and animal movement data were gathered from farm records and the Estonian Agricultural Registers and Information Board. The yearly calf mortality risk (%) during the first 21 days (YAG) and mortality rate between 22-90 days of age (OAG) adjusted for the animal time-at-risk were then calculated for each herd. Univariate negative binomial regression analysis was used to identify associations between calf mortality risk/rate, and the studied statements and variables with a p-value < 0.25 were included in a k-modes clustering analysis. The mean calf mortality risk was determined to be 5.9 % (range 0.0-26.8 %) during the first 21 days and mean calf mortality rate was 1.8 (range 0.0-9.2) deaths per 100 calf-months during 22-90 days of age. In both age group analyses, two FMs´ clusters formed based on 17 pre-selected statements. The FMs of the high-mortality cluster were found to be dissatisfied with the calf mortality levels. In the YAG analysis, FMs from high-mortality cluster gave lower priority to the issue of calf mortality, placed high importance on the influence of workers on calf mortality, and were more satisfied with the staff's performance compared to FMs of the cluster of herds with lower calf mortality. They were additionally less satisfied with their own performance and felt less recognized by the farm staff. They were also more inclined to try new products and practices on the farm and demonstrated greater empathy towards cattle. In the OAG analysis, the FMs from the higher-mortality cluster viewed reducing calf mortality more costly, had a less ambitious and target-driven management style, and rated their self-performance lower. This study determined that FMs working in herds with high calf mortality were dissatisfied and did not prioritize addressing calf mortality compared to managers working in farms with lower calf mortality. FMs' attitudes and management styles were associated with calf mortality, while the respondents' personality traits had little influence.

Microbial inoculum effects on the rumen epithelial transcriptome and rumen epimural metatranscriptome in calves.

Manipulation of the rumen microbial ecosystem in early life may affect ruminal fermentation and enhance the productive performance of dairy cows. The objective of this experiment was to evaluate the effects of dosing three different types of microbial inoculum on the rumen epithelium tissue (RE) transcriptome and the rumen epimural metatranscriptome (REM) in dairy calves. For this objective, 15 Holstein bull calves were enrolled in the study at birth and assigned to three different intraruminal inoculum treatments dosed orally once weekly from three to six weeks of age. The inoculum treatments were prepared from rumen contents collected from rumen fistulated lactating cows and were either autoclaved (control; ARF), processed by differential centrifugation to create the bacterial-enriched inoculum (BE), or through gravimetric separation to create the protozoal-enriched inoculum (PE). Calves were fed 2.5 L/d pasteurized waste milk 3x/d from 0 to 7 weeks of age and texturized starter until euthanasia at 9 weeks of age, when the RE tissues were collected for transcriptome and microbial metatranscriptome analyses, from four randomly selected calves from each treatment. The different types of inoculum altered the RE transcriptome and REM. Compared to ARF, 9 genes were upregulated in the RE of BE and 92 in PE, whereas between BE and PE there were 13 genes upregulated in BE and 114 in PE. Gene ontology analysis identified enriched GO terms in biological process category between PE and ARF, with no enrichment between BE and ARF. The RE functional signature showed different KEGG pathways related to BE and ARF, and no specific KEGG pathway for PE. We observed a lower alpha diversity index for RE microbiome in ARF (observed genera and Chao1 (p < 0.05)). Five microbial genera showed a significant correlation with the changes in host gene expression: Roseburia (25 genes), Entamoeba (two genes); Anaerosinus, Lachnospira, and Succiniclasticum were each related to one gene. sPLS-DA analysis showed that RE microbial communities differ among the treatments, although the taxonomic and functional microbial profiles show different distributions. Co-expression Differential Network Analysis indicated that both BE and PE had an impact on the abundance of KEGG modules related to acyl-CoA synthesis, type VI secretion, and methanogenesis, while PE had a significant impact on KEGGs related to ectoine biosynthesis and D-xylose transport. Our study indicated that artificial dosing with different microbial inocula in early life alters not only the RE transcriptome, but also affects the REM and its functions.

Effects of dam metabolic profile and seasonality (Spring vs. Winter) on their offspring' metabolism, health, and immunity: maternal factors in dairy calves' analytes.

Maternal status during the transition period can significantly impact the health and performance of Holstein dairy calves, with lasting effects on various variables. However, the relationship between maternal late gestation metabolic status, seasonality, and their impact on offspring remains unclear. This study aimed to assess the influence of maternal variables at calving on the performance, metabolism, and immunity of 28 dairy calves during their first month of life. Blood samples were collected from 28 Holstein cows at calving. Median results for maternal variables including non-esterified fatty acids (NEFA), ß-hydroxybutyrate (BHB), glucose, total protein (TP), albumin, triglycerides (TG), total cholesterol (TC), haptoglobin (Hp), body weight (BW), and body condition score (BCS) were determined. These median values served as a basis for categorizing the offspring into two groups based on their dams' high or low degree of each maternal variable. Additionally, calves were categorized by the season of birth (Spring vs. Winter), with 14 in each. Blood samples were collected from the calves at birth and on days 1, 7, 14, and 28 to assess IgG, biochemical parameters, and haptoglobin concentration. Reactive oxygen species (ROS) production by polymorphonuclear cells stimulated by various agents was also evaluated. Clinical assessments were conducted for diarrhea and bovine respiratory disease frequencies. Despite the overall health of the cows, differences were observed in the calves between maternal groups. Heavier cows with high maternal BCS tended to have larger offspring, while high maternal BCS was associated with increased diarrhea prevalence. Low maternal BCS resulted in a stronger innate immune response, indicated by higher ROS production. Calves from cows experiencing metabolic changes during calving displayed elevated Hp concentrations. Spring-born calves were larger but had lower serum IgG concentration and reduced innate immune response compared to winter-born calves. Additionally, spring-born calves exhibited higher Hp and increased diarrhea prevalence on day 28. These findings underscore the importance of the prenatal period in determining neonatal health and suggest further research to elucidate the long-term clinical implications of maternal effects on offspring health and growth. Investigating offspring constituents later in life can provide insight into the persistence of maternal effects over time.

Determining genetic diversity of prevalent G and P genotype of Bovine Rotavirus A from neonatal calves of Gujarat, India.

IMPORTANCE: Neonatal calf diarrhea is a major cause of mortality in newborn calves worldwide, posing a significant challenge in bovine herds. Group A Bovine Rotaviruses (BRVA) are the primary contributors to severe gastroenteritis in calves under two months old. OBJECTIVES: This study examined the prevalence and molecular characterization of BRVA in neonatal calves in Gujarat, India. METHODS: Sixty-nine diarrheic fecal samples were collected and subjected to various molecular methods of BRVA detection, isolation, and characterization. RESULTS: The latex agglutination test (LAT), electropherotyping (RNA-PAGE), and reverse transcription polymerase chain reaction revealed positivity rates of 39.13%, 20.30%, and 37.70%, respectively. RNA-PAGE identified 11 bands with a 4:2:3:2 migration pattern, indicative of the segmented genome of BRVA. BRVA was successfully isolated from LAT-positive samples, with 26 samples exhibiting clear cytopathic effects upon passage in MA-104 cell lines. Genotyping identified G10 as the predominant G genotype, with P[11] genotypes comprising 76.92% of the isolates. The most common G/P combination was G10P[11], highlighting its zoonotic potential. CONCLUSIONS AND RELEVANCE: These findings underscore the importance of molecular detection and genotyping for effective vaccine development. This study provides crucial insights into the prevalent G and P genotypes of BRVA in Gujarat, India, aiding in the development of targeted control measures.