Extended lactations in dairy cows and the effects on fertility and production.

Extending lactation length reduces the frequency of critical calving events for the cow and herewith reduces the frequency of periods with increased risk for health problems. Moreover, breeding is postponed until a moment later in lactation, which is associated with better conception rates and less days open after start of the breeding period in most studies. Potential risks of an extended lactation are that milk yield of cows at the end of the lactation may be too low which may lead to cows being overconditioned at the end of the extended lactation. Therefore, extending lactation length might not fit every cow. Individual cow characteristics like parity, milk yield level, or body condition determine the response of the cow to an extended lactation. These individual cow characteristics can be used in customized management strategies to optimize lactation length for individual cows. Customized lactation length for individual cows could limit the impact at herd level of disadvantages concerning milk losses and overconditioning and maintain benefits for improved cow health and fertility, reduced number of surplus calves and increased work satisfaction for the farmer. In conclusion, extending lactation length has interesting perspectives for health and fertility of high-producing dairy cows, although questions remain concerning management approaches to support lactation persistency of cows with an extended lactation, and consequences for calf health and development. Moreover, ongoing studies aim to develop decision support tools to select individual cows for a specific lactation length.

Investigating the regulatory effect of Shen Qi Bu Qi powder on the gastrointestinal flora and serum metabolites in calves.

Object: To investigate the effects of Shen Qi Bu Qi Powder (SQBQP) on the average daily gain, blood indexes, gastrointestinal microflora, and serum metabolites of calves. Methods: A total of 105 calves were randomly assigned to three groups (n = 35 per group): the control group (C, fed with a basal diet for 21 days) and two treatment groups (SQBQP-L and SQBQP-H, fed with the basal diet supplemented with 15 and 30 g/kg of SQBQP), respectively for 21 days. The active components of SQBQP were identified using LC-MS/MS. Serum digestive enzymes and antioxidant indices were determined by ELISA kits and biochemical kits, respectively. Serum differential metabolites were analyzed by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS), while flora in rumen fluid and fecal were analyzed by 16S rDNA sequencing. Further correlation analysis of gastrointestinal flora and serum metabolites of SQBQP-H and C groups were performed with Spearman's correlation. Results: The principal active components of SQBQP mainly includes polysaccharides, flavonoids, and organic acids. Compared to the control group (C), calves in the SQBQP-H (high dose) and SQBQP-L (low dose) groups showed a significant increase in serum amylase (AMS) levels (P<0.001), while lipase content significantly decreased (P<0.05). Additionally, the average daily gain, T-AOC, and cellulase content of calves in the SQBQP-H group significantly increased (P<0.05). Proteobacteria and Succinivibrio in the rumen flora of the SQBQP-H group was significantly lower than that of the C group (P<0.05). The relative abundance of Proteobacteria, Actinobacteria, Candidatus_Saccharibacteria, Deinococcus_Thermus, Cyanobacteria, and Succinivibrio in the SQBQP-H group was significantly increased (P<0.05), while the relative abundance of Tenericutes and Oscillibacter was significantly decreased (P<0.05). Serum metabolomics analysis revealed 20 differential metabolites, mainly enriched in amino acid biosynthesis, ß-alanine metabolism, tyrosine, and tryptophan biosynthesis metabolic pathways (P<0.05). Correlation analysis results showed that Butyrivibrio in rumen flora and Oscillibacter_valericigenes in intestinal flora were significantly positively correlated with average daily gain, serum biochemical indexes, and differential metabolite (-)-Epigallocatechin (R>0.58, P<0.05). Conclusion: SQBQP can promote calves weight gain and enhance health by modulating gastrointestinal flora and metabolic processes in the body.

Effects of Partial Replacement of Corn Grains With Mango Seed Kernel on Nutrient Digestibility, Blood Metabolites and Rumen Parameters of Growing Calves.

Fruit by-products are a sustainable and cost-effective alternative to traditional grain feed for livestock. One of the most important by-products is mango seed kernel (MSK), which can be used as a valuable energy source for feeding growing calves in the tropical and subtropical productive regions of the world. This study investigated the effect of replacing corn grains (CGs) with MSK on intake, nutrient digestibility, blood metabolites and rumen parameters. Eighteen growing male Friesian calves (200 ± 6.55 kg of body weight and 9-11 months old) were randomly assigned to three treatment groups. Three concentrate feed mixtures were formulated such that MSK replaced CG at 0%, 25% and 50%. Dry matter intake was unaffected, whereas dry matter, organic matter and fibre digestibility increased linearly (p < 0.05) with increased inclusion of MSK. Ruminal pH (p = 0.053) and total volatile fatty acid (VFA) concentration (p = 0.041) increased linearly. There was a linear decrease in cholesterol (p = 0.029) and AST (p = 0.028) levels in the blood of calves. In conclusion, this study demonstrated the positive effect of replacing 50% of CG with MSK on rumen parameters, including a higher ruminal pH and total VFA concentration, alongside higher nutrient digestibility. The dietary inclusion of mango seed can serve as a valuable and sustainable dietary component for growing calves.

Effect of various flavors in starter diets on growth, behavior, and blood parameters of Holstein calves.

This study investigated the effect of adding various flavors to calf starter concentrates on the performance, behavior, and blood parameters of Holstein dairy calves. The hypothesis was that an optimal flavor enhancer would increase starter intake, improve growth performance, and possibly enable earlier weaning without adverse physiological effects. In Experiment 1, a cafeteria test was conducted with 80 pre-weaned calves to evaluate four synthetic flavor enhancers (salty, sweet, sour, bitter) at levels of 3.3, 6.6, and 9.9 g/kg dry matter (DM), and a control without a flavor enhancer. Experiment 2 tested higher levels (9.9, 19.8, 29.7 g/kg DM) of the sweet flavor enhancer sodium saccharin in a single cafeteria test with 20 calves. Experiment 3 compared three sweet flavor enhancers (sodium saccharin, stevia, sucralose) at 9.9 g/kg DM in another cafeteria test with 20 calves. After selecting sodium saccharin at 9.9 g/kg DM as the optimal flavor enhancer, Experiment 4 was conducted with 40 calves divided into a treatment group receiving the flavored starter and a control group without flavor. In Experiment 1, sodium saccharin at 9.9 g/kg DM resulted in the highest dry matter intake (DMI) of 347 g/d, significantly higher than the control (173 g/d). Experiment 2 revealed a quadratic effect with DMI peaking at 9.9 g/kg DM sodium saccharin (201.0 g/d) and declining at higher levels. Experiment 3 confirmed that sodium saccharin outperformed other sweet flavor enhancers, increasing DMI to 350 g/d compared to 251 g/d for the control. In Experiment 4, calves fed the starter concentrate with 9.9 g/kg DM sodium saccharin showed significantly higher DMI (1749 g/d), average daily gain (ADG; 730 g/d), and feed conversion ratio (FCR; 2.05) compared to the control group (DMI 1470 g/d, ADG 650 g/d, FCR 2.36). Furthermore, calves in the flavored treatment were weaned earlier (59 days) than the control group (64 days). Behavioral observations showed that the sweet flavor treatment increased the time spent on solid feed intake, rumination, and standing behavior. Calves fed the flavored starter had lower levels of cholesterol, triglycerides, and blood urea nitrogen, suggesting improved nutrient utilization. Overall, the results demonstrated the potential benefits of incorporating sodium saccharin as a sweet flavor enhancer in calf starter concentrates, leading to improved feed intake, growth performance, feed efficiency, final body weight (FBW), and behavioral patterns during the critical pre-weaning and post-weaning periods.

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.

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.

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.

Lactobacillus salivarius and Berberine Alleviated Yak Calves' Diarrhea via Accommodating Oxidation Resistance, Inflammatory Factors, and Intestinal Microbiota.

Yaks are important food animals in China; however, bacterial diarrheal diseases frequently occur on the plateau, with limited effective therapies. The objective of this research was to evaluate the effectiveness of Lactobacillus salivarius (LS) and berberine in alleviating diarrhea in yak calves. For this purpose, eighteen healthy yak calves were divided into control (JC), infected (JM), and treatment (JT) groups. Yaks in the JT group were treated with 2 × 1010 CFU/calf L. salivarius and 20 mg/kg berberine, and yaks in the JM and JT groups were induced with multi-drug-resistant Escherichia coli. The results showed that the weight growth rate in the JM group was significantly lower than that in the JC and JT groups. The diarrhea score in the JM group was significantly higher than that in both the JC and JT groups. Additionally, the contents of T-AOC, SOD, GSH-Px, and IL-10 were significantly lower in the JM group than those in the JC and JT groups, while MDA, TNF-α, IL-1ß, and IL-6 were significantly higher in the JM group. Microbiota sequencing identified two phyla and twenty-seven genera as significant among the yak groups. Notably, probiotic genera such as Faecalibaculum and Parvibacter were observed, alongside harmful genera, including Marvinbryantia and Lachnospiraceae UCG-001. Our findings indicate that treatment with L. salivarius and berberine significantly reduced diarrhea incidence, improved growth performance, and positively modulated intestinal microbiota, which could provide novel insights for developing new therapies for ruminant diarrhea.

Molecular investigation of Blastocystis in children and calves in Bangladesh.

BACKGROUND: Blastocystis, a widely distributed zoonotic protozoan infecting both humans and numerous animals, remains poorly understood with its potential medical and veterinary significance. This study examined the molecular occurrence and genetic variation of Blastocystis in children and calves in Bangladesh to explore cross-species transmission and disease burden. METHODS: In total, 998 DNA samples were investigated, comprising 299 stool DNA from children and 699 fecal DNA from calves, using polymerase chain reaction and sequencing of the small subunit ribosomal RNA (SSU rRNA) gene. RESULTS: This study detected Blastocystis in 5.35% of the children and 14.74% of the calves. While slight variations in occurrence rates were observed across different study variables, none were statistically significant. The occurrence was highest among children under 5 years and calves aged 1-3 months. Regarding breed, the Holstein Friesian cross and the Jersey cross exhibited higher rates of infection. Conversely, occurrences were lower among children and calves in Gazipur district. The remaining parameters displayed nearly equivalent percentages of Blastocystis. The subtypes identified in children included ST1, ST3, and ST4, with ST1 comprising 50% of them. ST3 and ST4 were also found in calves, alongside ST10 (55.34%) being the most prevalent. Other subtypes found in calves were ST14, ST21, and ST24-ST26. CONCLUSIONS: This study found that Blastocystis is more common in calves than in children in Bangladesh, with genetic diversity of nine subtypes. The common occurrence of identical variants of two subtypes in both populations suggests potential zoonotic transmission, highlighting the necessity for further molecular investigations and comprehensive measures within the One Health framework to mitigate public health risks.

Evaluation of a data-driven youngstock rearing quality system in Dutch dairy herds (2019-2022).

In recent years, the Netherlands exhibited an increased focus on improving youngstock rearing. Several data-driven tools were developed to assess and benchmark calf rearing practices based on key indicators, stimulate farmers to improve their youngstock rearing and reduce calf mortality. KalfOK is such a data-driven tool in which a farm-level overview with 15 indicators of youngstock rearing quality is communicated to participating farmers. In this study we assessed which farm characteristics are associated with A) a continuously high or low KalfOK score and B) frequent usage of KalfOK. Data from KalfOK and the identification and registration system were available for all participating herds over a period between 2019 and 2022 (Dataset A). Additionally, a sample of 324 dairy farmers, randomly selected from the entire Dutch dairy population (Dataset B), participated in a voluntary survey. Multivariable (logistic) regression models were used to A) identify differences in characteristics between farms with a continuously high- and farms with a continuously low KalfOK score and B) assess which farm characteristics were associated with frequent use of the KalfOK report. The results of analysis A showed multiple factors associated with having a low or high KalfOK score, including replacement rate, closed farming system, limited growth in herd size and the region where a farm was located. Sociological factors might also partly explain the difference between high and low scoring farms. Analysis B showed that approximately half of the surveyed farmers indicated that they do not frequently use their KalfOK overview in their calf rearing management. The KalfOK score of farmers who regularly use their KalfOK report was higher - and consequently better - compared to the KalfOK score of farmers who sometimes or never use KalfOK. Additionally, farmers using a milk robot and those discussing KalfOK regularly with their veterinarian, used KalfOK more often. Thirty four percent of the surveyed farmers made adjustments to their youngstock rearing management since the start of participation. The study's insights into patterns in KalfOK utilization and associations with farm characteristics provide valuable information for ongoing efforts to enhance calf rearing practices via the use of KalfOK. It is important to consider what is needed to convince farmers that do not use the KalfOK tool to frequently start using their KalfOK report. Future research incorporating sociological aspects can provide a more comprehensive understanding of other dynamics influencing calf rearing and contribute valuable insights for enhancing the effectiveness of programs like KalfOK in promoting calf health and welfare.

Molecular Detection and Characterization of Cryptosporidium spp. and Giardia duodenalis in Dairy Calves from Ningxia, China.

PURPOSE: Cryptosporidium spp. and Giardia duodenalis are two important foodborne human and animal parasites that can be disseminated through both food and water, leading to diarrheal disease. Nevertheless, available information on the circumstances of Cryptosporidium and Giardia duodenalis from Ningxia is limited. METHODS: A total of 208 stool samples of dairy calves derived from large-scale farms (> 1000 heads) of five cities randomly in Ningxia were gathered randomly, were amplified and analyzed by nested PCR based on the three target genes (18S rRNA, gp60 and tpi)and phylogenetic systematics. RESULTS: The prevalence of cryptosporidiosis and giardiasis in dairy calves in Ningxia were 13.0% (27/208 samples, 95% CI 9.1-18.2%) and 1.9% (4/208, 95% CI 0.8-4.9%) respectively. Three Cryptosporidium species appeared in this study which are Cryptosporidium parvum (C. parvum), Cryptosporidium andersoni (C. andersoni) and Cryptosporidium ryanae (C. ryanae) based on the 18S rRNA gene sequence. IIdA15G1 and IIdA13G1 belonging to the subtypes of Cryptosporidium were detected by the gp60 PCR. The genotypes of Giardia duodenalis were only assemblage E through the amplification of the triosephosphate-isomerase gene (tpi gene). CONCLUSION: There is a risk of transmission to humans in Ningxia because of zoonotic genotypes (C. parvum, C. andersoni, assemblage E) and subtypes (IId) of Cryptosporidium spp. and G. duodenalis in dairy calves, and it is necessary to pay attention to the disease to prevent a widespread epidemic of the disease with the purpose to protect human and livestock health.

Determination of systemic inflammation response index (SIRI), systemic inflammatory index (SII), HMGB1, Mx1 and TNF levels in neonatal calf diarrhea with systemic inflammatory response syndrome.

The objective of this study was to examine the values of MX dynamin-like GTPase 1 (Mx1), high mobility group box-1 (HMGB1), systemic inflammatory response index (SIRI), systemic inflammatory index (SII), tumor necrosis factor (TNF), and other hematological indices in calves with systemic inflammatory response syndrome (SIRS). The study material was divided into two groups: the SIRS group (comprising 13 calves) and the control group (comprising 10 calves). The independent samples t-test and Mann-Whitney U test were employed for normally distributed and non-normally distributed data, respectively. The relationship between the two groups was determined using Spearman correlation coefficient analysis. Significant differences were identified between the SIRS group and the control group with regard to white blood cell (WBC; P < 0.05), neutrophil (NEU; P < 0.01), and neutrophil-to-lymphocyte ratio (NLR; P < 0.001) values, in addition to SIRI (P < 0.05), SII (P < 0.01) values. Furthermore, HMGB1 (P < 0.001), Mx1 (P < 0.05), and TNF values (P < 0.001) demonstrated notable disparities between the two groups. As a result of this study, it was concluded that there were significant increases in inflammatory hematological indices, as well as in the levels of HMGB1, Mx1, and TNF, in calves with SIRS.

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.

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.

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.

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.

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.

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.