Effects of castration and eucalyptus oil supplementation on growth performance, nutrient digestibility, and blood-immunity indicators of male Holstein calves.

The purpose of this study was to investigate the effects of early castration and eucalyptus oil (EUC) supplementation on dry matter intake (DMI), growth performance, and immune response of Holstein calves. Fifty-six male Holstein calves 52 d old and with an initial body weight (BW) of 63.5 ± 5.27 kg were used. The animals were blocked by BW and randomly assigned into 1 of the 4 treatment groups in a randomized complete block design with a 2 (no castration vs. castration) × 2 (without vs. with EUC) factorial arrangement of treatments. The treatments were (1) uncastrated calves fed without EUC, (2) uncastrated calves fed 0.5 g/d EUC (EUC group), (3) castrated calves (steers) fed without EUC (castrated group), and (4) steers fed with 0.5 g/d EUC (castrated + EUC). The experiment was 8 wk long, including pre- and postweaning (weaned at 72 d). The EUC × castrated interactions were not significant for DMI, growth performance, nutrient digestibility, and immune response. Castration did not affect the DMI, final BW, average daily gain (ADG), or feed efficiency, except that the ADG was greater for bull calves than for steers at postweaning. Supplementation with EUC increased DMI pre- and postweaning and increased the ADG of weaned calves. Digestibility in the total digestive tract was not affected by castration (except for organic matter digestibility), whereas adding EUC improved the digestibility of dry matter, acid detergent fiber, and crude protein. Blood concentration of IL-6 at d 94 was decreased by feeding EUC. These results indicate that the EUC could be fed to either intact or castrated dairy calves to promote growth and health postweaning; castration before weaning may reduce ADG and cause inflammatory stress without affecting feed intake or feed efficiency.

Effects of meloxicam on the welfare of Holstein calves from 6 weeks to 6 months old undergoing amputation dehorning.

Amputation dehorning (AD) is a common practice performed on calves, causing harmful effects such as pain, distress, anxiety, and fear. These effects extend to behavioral, physiological, and hematological responses, prompting serious ethical concerns regarding animal welfare, even when performed with local anesthesia. Meloxicam, a nonsteroidal anti-inflammatory drug, has been widely used to mitigate the side effects of dehorning and disbudding in calves. However, there is a notable gap in research regarding the effects of meloxicam on calves aged 6 wk to 6 mo undergoing AD procedures. This study was designed to assess the effectiveness of co-administering meloxicam with lidocaine, a cornual nerve anesthetic, in alleviating the adverse effects caused by the AD procedure in calves within this age range, compared with the use of lidocaine alone. Thirty Holstein calves were enrolled and randomly divided into 2 groups. The first group received a subcutaneous injection of 5 mL of lidocaine in the horn area and a subcutaneous injection of 0.9% saline at a dose of 0.025 mL/kg in the neck, administered 10 min before the AD procedure. The second group received a combination of lidocaine and meloxicam: a subcutaneous injection of 5 mL of lidocaine in the horn area and a subcutaneous injection of 20 mg/mL meloxicam at a dose of 0.025 mL/kg in the neck, also administered 10 min before the AD procedure. To avoid subjective bias, the researchers were blinded to the treatment groups. Pain-related behaviors, including tail flicking, head shaking, ear flicking, head rubbing, head crossing bar, and kicking, were observed, and physiological parameters, including heart rate, rectal temperature, respiration rate, mechanical nociceptive threshold (MNT), daily active steps, and food intake were monitored. Hematological conditions were determined using enzyme-linked immunosorbent assays and routine blood tests. The data were processed using a generalized linear mixed model. The outcomes demonstrated that the AD procedure increased the frequencies of ear flicking and resulted in rises in the respiration rate, heart rate, rectal temperature, and daily active steps. It also led to decreases in total food intake, forage intake, hay intake, MNT, and increased concentrations of prostaglandin E2 (PgE2), IL-1ß, tumor necrosis factor-α (TNF-α), nitric oxide (NO), and malondialdehyde, as well as glutathione peroxidase activity. However, calves that received meloxicam treatment showed significant improvements in response to the AD procedure, including lower respiration rates, heart rates, and rectal temperatures; higher MNT; and lower intermediate cell ratio. They also had higher red blood counts, hemoglobin levels, hematocrit values; larger mean platelet volumes; and lower concentrations of PgE2, IL-1ß, TNF-α, and NO. These results suggest that co-administration of lidocaine and meloxicam may aid in mitigating the adverse effects induced by the AD procedure on these calves, thereby supporting the use of meloxicam in conjunction with a local anesthetic in AD procedures for calves aged 6 wk to 6 mo.

Climatic and calf-related risk factors associated with failure of transfer of passive immunity in Holstein calves in a hot environment.

This retrospective observational study aimed to assess the effect of temperature-humidity index (THI) at calving and in the last trimester of pregnancy and calve-related factors affecting passive transfer of maternal immunoglobulin using Brix refractometry in Holstein calves. Blood samples from 4411 Holstein calves from a single large dairy farm in spring 2022 were used. A subset of data containing 6318 calvings was used to determine the effect of climatic conditions on the occurrence of agammaglobulinemia. Risk factors predictive of failure of passive transfer (FPT) were calculated using multiple logistic models. Females were 1.4 times more likely not to have FPT (56%; Brix% > 8 equivalent to ≥ 10 g/L IgG) than males (47.2%). Calves born as singles increased the likelihood of not presenting FPT (52.6%) than calves born as twins (42.9%). Calves from cows with no dystocic delivery had a lower risk for FPT (odds ratio = 2.3) than calves from cows with dystocia. Agammaglobulinemia was 1.5 and 1.8 times more likely to occur in calves with THI ≥ 80 and ≥ 82 in the last trimester of gestation and at calving, respectively, than in calves not experiencing heat stress. Agammaglobulinemia was twice as likely to occur in male than in female calves. Calves with birth weight ≥ 37 kg and gestation length ≥ 275 kg were less likely to present agammaglobulinemia than lighter calves and calves with shorter gestation periods. This study raises questions for management practices in Holstein calves undergoing in utero heat stress and around calving to avoid agammaglobulinemia.

Integrating RNA-sequencing and untargeted LC-MS metabolomics to evaluate the effect of lysine deficiency on hepatic functions in Holstein calves.

Lysine (Lys) is majorly metabolized in the liver. The liver functional consequences of a dietary Lys deficiency in young Holstein calves are unknown. This study aimed to investigate the effects of Lys deficiency in Holstein calf livers using RNA-sequencing and untargeted LC-MS metabolomics. Calves (n = 36; initial body weight 101.2 ± 10.8 kg; 90-day-old) were fed restricted diets, for 90 days, containing 19.2% crude protein that varied in Lys content (PC group 1.21%; PC-Lys group 0.85%; dry matter basis) for 90 days. Body weight, average daily gain, gain/feed, and Lys intake were significantly decreased in response to Lys deficiency (P < 0.05). Dry matter intake was not altered (P > 0.05). Network and pathway analyses revealed that noradrenaline, adenosine 5'-monophosphate, acetyl-CoA, and coenzyme A were significantly decreased. Regulating of lipolysis in adipocytes pathway and fatty acid degradation pathway were downregulated. We also identified eight significantly differentially expressed genes (SDEGs), among which adrenoceptor beta 2 (ADRB2), WAP four-disulfide core domain 2 (WFDC2), and claudin-4 (CLDN4) were associated with inhibition of lipolysis, and carbon catabolite repression 4-like (CCRN4L), FOS like 2 (FOSL2), and arginase 2 (ARG2) were associated with inhibiting lipid synthesis. Correlation tests showed that coenzyme A was strongly correlated with SDEGs (0.82 ≤|r|≤ 0.96). Acetyl-CoA and adenosine 5'-monophosphate were strongly correlated with CCRN4L (0.90 ≤|r|≤ 0.92), indicating a strong correlation between the changes in SDEGs and these metabolites. In conclusion, Lys deficiency caused dysplasia and affected lipid metabolism in the liver by inhibiting lipolysis and lipid synthesis in calves.

Effect of supplementation fat during the last 3 weeks of uterine life and the preweaning period on performance, ruminal fermentation, blood metabolites, passive immunity and health of the newborn calf.

The objective of this study was to evaluate the effects of supplementing essential fatty acids (FA), during late gestation and the preweaning and early weaning periods on passive immunity, growth, health, rumen fermentation parameters, blood metabolites and behaviour of dairy calves. During the last 3 weeks of pregnancy, cattle (n 120), within parity, were randomly assigned to one of three diets with different fat supplements: (a) no supplemental fat (CON), (b) supplement rich in linoleic acid (CSO), or (c) supplement rich in EPA and DHA (CFO). Eighty-four newborn Holstein calves were randomly assigned, within the prepartum diets, to one of two calf starters: no fat supplement (FC-0) or 2 % Ca-salt of unsaturated FA (FC-2). Overall, the interaction between dam diets and calf starters did not affect calf performance or any other parameter measured. Calves born from dams fed fat (CSO or CFO) performed better than calves born from dams fed CON. Namely, calves born from dams fed fat had greater plasma concentrations of IgG (P < 0·01), better apparent efficiency of IgG absorption (P < 0·01) and average daily gain (ADG, 597 v. 558 g/d; P = 0·02), and lower rectal temperature (RT; P < 0·01). Calves fed a calf starter rich in unsaturated FA (FC-2) had greater (P ≤ 0·01) ADG, skeletal growth, feed efficiency, and weaning weight compared with FC-0-fed calves. Furthermore, calves fed FC-2 had lower RT during the pre- and post-weaning periods (P ≤ 0·04) and fewer days with diarrhoea (P < 0·001) compared with calves fed CF-0. Time spent eating, ruminating, standing, lying, and on non-nutritive oral behaviour did not differ by treatment. Similarly, treatments did not affect ruminal fermentation parameters. At 28 and 77 d of age, calves fed CF-2 had higher plasma concentrations of albumin and cholesterol (P ≤ 0·02) and lower urea N compared with calves fed CF-0. Plasma concentrations of alkaline phosphatase were higher in calves fed CF-2 compared with those fed CF-0, when they were 77 d old. These findings support feeding moderate amounts of long-chain PUFA during late uterine life or during the preweaning period have beneficial effects on calf metabolism, growth, and health performance.

Transcriptome analysis and identification of significantly differentially expressed genes in Holstein calves subjected to severe thermal stress.

RNA-Seq analysis was used to characterize transcriptome response of Holstein calves to thermal stress. A total of eight animals aged between 2 and 3 months were randomly selected and subjected to thermal stress corresponding to a temperature humidity index of 95 in an environmentally controlled house for 12 h consecutively for 3 days. A set of 15,787 unigenes were found to be expressed and after a threshold of threefold change, and a Q value <0.05; 502, 394, and 376 genes were found to be differentially expressed on days 1, 2, and 3 out of which 343, 261 and 256 genes were upregulated and 159, 133, and 120 genes were downregulated. Only 356 genes out of these were expressed on all 3 days, and only they were considered as significantly differentially expressed. KEGG pathway analysis revealed that ten pathways were significantly enriched; the top two among them were protein processing in endoplasmic reticulum and MAPK signaling pathways. These results suggest that thermal stress triggered a complex response in Holstein calves and the animals adjusted their physiological and metabolic processes to survive. Many of the genes identified in this study have not been previously reported to be involved in thermal stress response. The results of this study extend our understanding of the animal's response to thermal stress and some of the identified genes may prove useful in the efforts to breed Holstein cattle with superior thermotolerance, which might help in minimizing production loss due to thermal stress.

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.

Intake of compound probiotics accelerates the construction of immune function and gut microbiome in Holstein calves.

Acquired immunity is an important way to construct the intestinal immune barrier in mammals, which is almost dependent on suckling. To develop a new strategy for accelerating the construction of gut microbiome, newborn Holstein calves were continuously fed with 40 mL of compound probiotics (containing Lactobacillus plantarum T-14, Enterococcus faecium T-11, Saccharomyces cerevisiae T-209, and Bacillus licheniformis T-231) per day for 60 days. Through diarrhea rate monitoring, immune index testing, antioxidant capacity detection, and metagenome sequencing, the changes in diarrhea incidence, average daily gain, immune index, and gut microbiome of newborn calves within 60 days were investigated. Results indicated that feeding the compound probiotics reduced the average diarrhea rate of calves by 42.90%, increased the average daily gain by 43.40%, raised the antioxidant indexes of catalase, superoxide dismutase, total antioxidant capacity, and Glutathione peroxidase by 22.81%, 6.49%, 8.33%, and 13.67%, respectively, and increased the immune indexes of IgA, IgG, and IgM by 10.44%, 4.85%, and 6.12%, respectively. Moreover, metagenome sequencing data showed that feeding the compound probiotics increased the abundance of beneficial strains (e.g., Lactococcus lactis and Bacillus massionigeriensis) and decreased the abundance of some harmful strains (e.g., Escherichia sp. MOD1-EC5189 and Mycobacterium brisbane) in the gut microbiome of calves, thus contributing to accelerating the construction of healthy gut microbiome in newborn Holstein calves. IMPORTANCE: The unstable gut microbiome and incomplete intestinal function of newborn calves are important factors for the high incidence of early diarrhea. This study presents an effective strategy to improve the overall immunity and gut microbiome in calves and provides new insights into the application of compound probiotics in mammals.

Analysis of Fecal Microbial Changes in Young Calves Following Bovine Rotavirus Infection.

The objective of the present study was to identify changes in fecal microbiota and predict the functional features of healthy calves and those infected with rotavirus over time. Six Holstein calves (average body weight 43.63 ± 1.19 kg, age-matched within 5-7 d) were randomly selected and distributed into two groups which contained three calves each. Fecal samples were taken 3 days before inoculation and on days 1 and 7 post-inoculation. The 16S rRNA gene amplicon sequencing was performed. Bacterial diversity tended to decrease in the rota group, as indicated by the alpha (evenness, p = 0.074 and Shannon, p = 0.055) and beta (Bray-Curtis dissimilarity, p = 0.099) diversity at 1 day post-inoculation. Differences in the bacterial taxa between healthy and rota-infected calves were detected using a linear discriminant analysis effect size (LDA > 2.0, p < 0.05). Rota calves had a higher abundance of certain bacterial taxa, such as Enterococcus, Streptococcus, and Escherichia-Shigella, and a lower abundance of bacteria that contribute to the production of short-chain fatty acids, such as Alistipes, Faecalibacterium, Pseudoflavonifractor, Subdoligranulum, Alloprevotella, Butyricicoccus, and Ruminococcus, compared to the healthy calves. The observed changes in the fecal microbiota of the rota-infected group compared to the healthy group indicated potential dysbiosis. This was further supported by significant differences in the predicted functional metagenomic profiles of these microbial communities. We suggest that calves infected with bovine rotavirus had bacterial dysbiosis, which was characterized by lower diversity and fewer observed genera than the fecal microbiota of healthy calves.

Welfare implications on management strategies for rearing dairy calves: A systematic review. Part 2 - Social management.

Introduction: Raising a healthy calf up to puberty is essential for optimal farm performance. It is therefore, it is necessary to promote animal welfare from the three spheres during this short period. Social management has been postulated as essential in lowering stress and consequently improving calf welfare during this period. Only the health sphere has been studied for a long time, but more recent studies have recently promoted positive experiences and emotional states from affective states or cognitive judgment and natural living spheres. A systematic review of different management strategies in rearing dairy calves according to the three spheres of animal welfare has been conducted using an electronic search strategy. Methods: The analysis and extraction of information from the studies were performed according to a protocol. From 1,783 publications screened, only 351 met the inclusion criteria. Results: The publications identified in the search can be divided into two main groups, feeding and social management, based on the main topic of the publication. This review provides an overview of social management, understood as the calf's interaction with others around it. Discussion: Primary social management issues that emerged were social housing with congeners, separation from the mother and human-animal interaction, distributed in the three broad spheres of animal welfare. The review highlights unresolved questions about how social management practices affect the three spheres of animal welfare at this life stage and the need to standardize good socialization practices for this stage. In conclusion, all the information shows that social housing has improved animal welfare from affective states, cognitive judgment, and natural living spheres. However, gaps in research were identified in relation to the optimal time to separate the calf from the mother, the optimal time to group with conspecifics after birth and group size. Further research on positive welfare through socialization are needed.

Welfare implications on management strategies for rearing dairy calves: A systematic review. Part 1-feeding management.

Introduction: Calves are very susceptible to stress in the early stages of life, and it is necessary to ensure maximum welfare. Feeding management has been identified as a major risk factor for calf health and welfare at this stage. However, the management protocol for calf rearing and its impact on animal welfare is unclear. A systematic review of different management strategies for rearing dairy calves according to the three spheres of animal welfare was conducted using an electronic search strategy. In this review, management strategies were studied to identify scientific gaps, to know the welfare problems of these animals in order to prioritize actions and future research and to study the interpretive approach of this management from the three welfare spheres. Methods: A protocol was used to analyze and extract information from the studies. Of the 1,783 publications screened, only 351 met the inclusion criteria for the management or welfare of calves' items. Results: The publications identified in the search can be divided into two main groups feeding and socialization, based on the main topic of the publication. The main topics that emerged from the search in the feeding management group were milk replacer, colostrum, and weaning, divided into the three main areas of biological functioning and health, natural life and affective states or cognitive judgement. Discussion: The main issues to be addressed were the different types of feed consumed by animals from birth to weaning and the weaning management. It has been found that the most researched issues are colostrum and solid starter feed management. Unresolved issues were highlighted, such as the lack of a clear protocol for the administration of milk replacers to reduce hunger and the best management of weaning to reduce stress.

Effects of probiotic and prebiotic on average daily gain, fecal shedding of Escherichia coli, and immune system status in newborn female calves.

Thirty two Holstein female calves (initial body weight = 40±3.0 kg) were used to investigate the effects of probiotic and prebiotic on average daily gain (ADG), fecal E. coli count, white blood cell count, plasma IgG1 level and cell-mediated immune response to injection of phytohemagglutinin in suckling female calves. Calves were assigned randomly to one of the four treatments, including whole milk without additives (control), whole milk containing probiotic, whole milk containing prebiotic and whole milk containing probiotic and prebiotic (synbiotic). Average daily gain was greater in calves fed probiotic, prebiotic and synbiotic at weeks 6, 7 and 8 (p<0.05). E. coli count was significantly lower in calves fed probiotic, prebiotic and synbiotic on d 56 (p<0.05). There was no significant difference between treatments in blood samples and cell-mediated response. This study showed that addition of probiotic, prebiotic and combination of these additives to milk enhanced ADG and reduced fecal E. coli count in preruminant calves.

Development of Next-Generation Probiotics by Investigating the Interrelationships between Gastrointestinal Microbiota and Diarrhea in Preruminant Holstein Calves.

(1) Background: We aimed to isolate and identify potential next-generation probiotics (NGP) by investigating the interrelationships between gastrointestinal microbiota and diarrhea in preruminant Holstein calves. (2) Material and methods: Twenty preruminant Holstein calves were divided into healthy and diarrheic groups after the combination outcomes of veterinary diagnosis and fecal scores. The fecal microbiome, plasma cytokines, plasma immunoglobulin (Ig) G and haptoglobin were analyzed. The potential probiotic bacteria were identified by comparing the microbiota difference between healthy and diarrheic calves and correlation analysis with fecal scores and inflammatory markers. The identified bacteria were also isolated for further evaluation for antimicrobial activities and immunoregulatory effects. (3) Results: Microbiota analysis suggested that Ruminococcaceae_UCG_014, Bifidobacterium and Pseudoflavonifractor positively correlated with bovine IgG and negatively correlated with fecal score; inflammatory factors, bovine HP, and IL-8 were classified as beneficial bacteria contributing to the health of the calves. The alternation of gut microbial composition also induced changes in the functional gene enrichment of gut microbiota in calves. The gathering of microbiomic data strongly indicated the possible beneficial effects of Bifidobacterium longum subsp. longum, expected to develop as NGP. After isolation and evaluation of the potential functionality in vitro, two specific bifidobacterial strains demonstrated antimicrobial activities and immunoregulatory effects. (4) Conclusions: The results provide a new probiotic searching approach for preventing gastrointestinal disorders in preruminant calves. Further animal study is necessary to verify the results.

Influence of a Polyherbal Mixture in Dairy Calves: Growth Performance and Gene Expression.

A polyherbal feed mixture containing (Achyrantes aspera, Trachyspermum ammi, Citrullus colocynthis, Andrographis paniculata, and Azadirachta indica) was evaluated in growing calves through blood chemistry, blood biometry, and gene expression during the pre-ruminant to weaning period. Forty Holstein calves (initial BW 45.6 ± 3.2 kg; 22.8 ± 0.9 days post birth) from a dairy farm were randomly assigned to the following treatments: 0, 3, 4, and 5 g/d of a polyherbal mixture, dosed in colloid gels with gelatin. Calves were housed in individual outdoor boxes with ad libitum access to a 21.5% CP calf starter and water and fed individually with a mixture of milk and a non-medicated milk replacer (22% CP). Blood samples were collected on day 59 for blood chemistry, blood biometry, and gene expression analysis in leukocyte through microarray assays. Immunoglobulins were quantified by enzyme-linked immunosorbent assay. The animals treated with the polyherbal mixture showed a quadratic effect on final body weight, daily weight gain, final hip height, and final thoracic girth. The best performance results were obtained with a treatment dose of 4 g/d. The serum IgG increased linearly with the treatment doses. Gene set enrichment analysis of upregulated genes revealed that the three biological processes with higher fold change were tight junction, mucin type O-Glycan biosynthesis, and intestinal immune network for IgA production. Also, these upregulated genes influenced arachidonic acid metabolism, and pantothenate and CoA biosynthesis. Gene ontology enrichment analysis indicated that the pathways enriched were PELP1 estrogen receptor interacting protein pathways, nuclear receptors in lipid metabolism and toxicity, tight junction, ECM-receptor interaction, thyroid hormone signaling pathways, vascular smooth muscle contraction, ribosome function, glutamatergic synapse pathway, focal adhesion, Hippo, calcium, and MAPK signaling pathways.

Weaning Holstein Calves at 17 Weeks of Age Enables Smooth Transition from Liquid to Solid Feed.

Development of calves depends on prenatal and postnatal conditions. Primiparous cows were still maturing during pregnancy, which can lead to negative intrauterine conditions and affect the calf's metabolism. It is hypothesized that weaning calves at higher maturity has positive effects due to reduced metabolic stress. We aimed to evaluate effects of mothers' parity and calves' weaning age on growth performance and blood metabolites. Fifty-nine female Holstein calves (38.8 ± 5.3 kg birth weight, about 8 days old) were used in a 2 × 2 factorial experiment with factors weaning age (7 vs. 17 weeks) and parity of mother (primiparous vs. multiparous cows). Calves were randomly assigned one of these four groups. Live weight, live weight gain and morphometry increased over time and were greater in calves weaned later. Metabolic indicators except total protein were interactively affected by time and weaning age. Leptin remained low in early-weaned calves born to primiparous cows, while it increased in the other groups. The results suggest that weaning more mature calves has a positive effect on body growth, and calves born to primiparous cows particularly benefit from this weaning regimen. It also enables a smooth transition from liquid to solid feed, which might reduce the associated stress of weaning.

Abomasal displacement in neonatal dairy calves: Review of recent literature with special emphasis on abomasal torsion.

AIM: This study aimed to describe the clinicopathological and necropsy findings in neonatal dairy calves affected with right torsion of the abomasum. MATERIALS AND METHODS: The history and findings of clinical examination, hematology and serum biochemical analyses and necropsy were described in six neonatal Holstein calves with a confirmed diagnosis of right torsion of the abomasum. Furthermore, a review of the literature was carried out using internet search engines such as PubMed and Google Scholar concerning abomasal displacement in calves. Only published papers in scientific and refereed journals were reviewed. RESULTS: Six neonatal Holstein calves (four females and two males) aged between 7 and 21 days were diagnosed with right torsion of the abomasum during necropsy. The calves were presented with peracute signs of anorexia, dehydration, abdominal pain, and abdominal distension. Hematology and serum biochemical analyses revealed hemoconcentration and azotemia, hyponatremia, hypochloremia, and hypokalemia. CONCLUSION: Abomasal torsion in neonatal calves must be placed on the deferential diagnostic list of calves suffering from peracute signs of abdominal pain and distension. Although the underlying etiopathological factors are not fully known, correction of nutritional mismanagement is required to prevent the condition.

[Thermographic examination of head surface temperatures of calves under field conditions]. / Thermographische Erfassung der Oberflächentemperatur im Kopfbereich von Kälbern unter Stallbedingungen.

INTRODUCTION: Thermographic examination of 157 German Holstein heifer calves was performed to investigate the feasibility of this technique for on-farm recording of surface temperature of the head and to examine potential factors that affect the recordings. Baseline values were obtained from six defined locations on the head including both eyes, both horn buds, the muzzle and the mucous membrane of the muzzle using a high-end thermographic camera (ThermoPro TP8, Firma DIAS Infrared GmbH). Evaluation of the influence of various factors on thermographic measurements showed that ambient temperature had the largest effect on surface temperature of the head (regression coefficient, 0.10 to 0.32, p ≤ 0.01) whereas humidity had no effect (in t-test p ≥ 0.33 over all locations). There was a no correlation between rectal temperature and surface temperature (rp ≤ 0.05). The surface temperature decreased with increasing age of the calves (regression coefficient, - 0.42 to - 0.14, p ≤ 0.01). The agreement between double readings made shortly after one another was excellent at all locations (r ≥ 0.95). The emission of infrared energy varied among different locations; the most infrared energy was emitted by the eyes and the least by the muzzle. Paired locations (eyes and horn buds) had symmetric emission patterns of infrared energy. Measuring the surface temperature of the head of calves in their normal barn environment using a standardised protocol was feasible and thus could potentially be used for monitoring calves under field conditions.

INTRODUCTION: Un total de 157 veaux femelles provenant d'un troupeau de 1 500 vaches holstein ont été examinées au moyen d'une caméra thermographique haut de gamme (Ther-moPro TP8, Firma DIAS Infrared GmbH). Le but de la présente étude était d'étudier la faisabilité de cette technique pour l'enregistrement à la ferme de la température de surface de la tête de veaux laitiers et d'examiner les facteurs potentiels qui affectent les enregistrements. Tous les veaux ont été doucement tenus par une personne formée afin de normaliser la procédure. Les valeurs de base ont été obtenues à partir de six endroits définis sur la tête, y compris les deux yeux, les deux boutons de corne, le mufle et la muqueuse du museau. L'évaluation de l'influence de divers facteurs sur les mesures thermographiques a montré que la température ambiante avait le plus grand effet sur la température de surface de la tête (coefficient de régression, 0,10 à 0,32, p ≤ 0,01) alors que l'humidité n'avait aucun effet (dans le test t, p ≥ 0,33 sur tous les lieux). Il n'y avait pas de corrélation entre la température rectale et la température de surface (rp ≤ 0,05). La température de surface diminuait avec l'âge des veaux (coefficient de régression, -0,42 à -0,14, p ≤ 0,01). La concordance entre les lectures doubles faites peu de temps après les autres était excellente dans tous les sites (r ≥ 0,95) L'émission d'énergie infrarouge variait selon les endroits. L'énergie infrarouge la plus importante a été émise par les yeux et la plus faible par le mufle. Les sites appariés (yeux et cornes) présentaient des profils d'émission symétriques d'énergie infrarouge. La thermographie peut être utilisée chez veaux Holstein pour la détection de différentes température de surface de la tête.

Influence of early use of antimicrobial on the health and performance of Holstein calves in the first month of life / Influência do uso precoce de antimicrobiano na sanidade de bezerras holandesas no primeiro mês de vida

The early use of antimicrobial therapy has been introduced in many farms to prevent diarrhea and respiratory disease in young calves; however, there is controversy about whether this practice has a beneficial effect on the health of these animals. This study evaluated the influence of the early use of antimicrobials on the health and performance of neonatal Holstein calves. Twenty-six Holstein calves were screened and divided into two groups, according to the administration (ATB+), or not (ATB-) of tulathromycin (2.5mg/kg, subcutaneously) within the first 12 hours of life. Calves were evaluated by general clinical examination, fecal score, respiratory score, and external palpation of the umbilical region, besides fecal output of dry matter. Anemia was determined by using an automatic system and, also, using a commercial kit for iron dosage. Diarrhea was diagnosed by a centrifuge-flotation technique using a sugar solution (Cryptosporidium) and multiplex semi-nested RT-PCR (rotavirus/coronavirus). The performance of the calves was estimated by Daily Weight Gain (DWG). The young dairy calves were evaluated within 12 hours of birth (≤12h) and at 3-5th (D3-5), 7-9th (D7-9), 13-15th (D13-15), 20-23rd (D20-23), and 27-30th (D27-30) days of life. No difference was noted between the ATB+ and ATB- groups concerning heart rate, respiratory frequency, and rectal temperature. Erythrogram showed a higher frequency of anemia in ATB- group (P=0.016) at the D3-5 check-up; lower values of serum iron were also observed simultaneously (P=0.051). Thirteen cases of respiratory disease were detected during this study; however, no significant difference was observed between the groups in this regard. The frequency of diarrhea (fecal score 2-3) was high in both groups, peaking at D13-D15. No differences were noted between the groups regarding the frequency of diarrhea when considering the dry fecal matter. The predominant etiological agent for diarrhea was Cryptosporidium spp.. The DWG was similar between groups, with maximum weight reduction on D13-15. The administration of tulathromycin in prophylactic dose (2.5mg/kg) at birth decreased the frequency of anemia but did not influence weight gain or the prevalence of diarrhea.(AU)

O uso precoce de antimicrobianos tem sido adotado em muitas fazendas para profilaxia das diarreias e doença respiratória em bezerras, no entanto existem controvérsias sobre os beneficios desta prática na saúde desses animais. Esta pesquisa avaliou a influência do uso precoce de antimicrobiano na sanidade e desempenho de bezerras holandesas recém-nascidas. Para tanto foram selecionadas 26 bezerras Holandesas distribuídas de acordo com a aplicação (ATB+) ou não (ATB-) de tulatromicina (2,5mg/Kg) por via subcutânea até 12h de vida. As bezerras foram examinadas por meio de exame clínico geral, escore fecal, escore respiratório e palpação externa da região umbilical, além da matéria seca fecal. A presença de anemias foi determinada pelo eritrograma utilizando sistema automático e além da dosagem de ferro utilizando kit comercial. O diagnóstico etiológico das diarreias foi investigado por meio da técnica de flutuação em solução saturada de sacarose (Cryptosporidium) e multiplex semi-nested RT-PCR (rotavírus/coronavírus). O desempenho das bezerras foi estimado pelo ganho de peso. As bezerras foram avaliadas até doze horas após o nascimento (≤12h); 3-5º (D3-5); 7-9º (D7-9); 13-15º (D13-15); 20-23º (D20-23); e 27-30º dias de vida (D27-30). Não foram encontradas diferenças entre os grupos ATB+ e ATB- em relação à frequência cardíaca, frequência respiratória e temperatura retal. O eritrograma revelou maior frequência de anemias no grupo ATB- (P=0,016) no D3-5. Neste momento também foram observados menores valores de ferro sérico (P=0,051). Foram detectados treze casos de doença respiratória durante o estudo, no entanto não foi possível detectar diferença entre os grupos. A frequência de diarreias (escore fecal 2 e 3) foi alta em ambos os grupos, observando-se pico no D13-15 (ATB+=92,3%; ATB-=92,3%). Não observamos diferenças entre os grupos em relação a frequência de diarreia considerando-se a matéria seca fecal. O agente etiológico predominante nas diarreias foi o Cryptosporidium. O ganho de peso diário foi igual entre grupos, com intensa redução no GPD no D13-15. A administração de tulatromicina na dose profilática (2,5mg/Kg) ao nascimento diminuiu a frequência de anemias e não influenciou no ganho de peso e prevalência de diarreias.(AU)

Physico-chemical Meat Qualities of Loin and Top Round Beef from Holstein Calves with Different Slaughtering Ages.

The objective of this study was to investigate the physico-chemical and sensory properties of loin (m. longissimus dorsi) and top round (m. semimembranosus) beef from 3-, 6-, 9-, and 12 mon-old Holstein calves. For both loin and top round muscles, the moisture contents were decreased, whereas the protein and fat contents were increased, as the slaughtering age increased. In terms of meat color, for both muscle types, CIE L* values were decreased, whereas CIE a* values and myoglobin content increased as the slaughtering age increased. pH values were significantly higher in the 3 mon-old group than in the other groups. The Warner-Bratzler shear force (WBSF) values were lowest for loin muscles from the 12 mon-old group; however, there was no significant difference for top round muscle among the 4 age groups. Cooking loss for both loin and top round muscles were significantly higher for the 3 mon-old group than for the other groups. The water holding capacity (WHC) of both muscles were highest for the 12 mon-old groups (p<0.05). In fatty acid composition of the 12 mon-old groups, loin muscles had significantly higher levels of C14:0, C16:1n7, C18:1n9, and mono-unsaturated fatty acids (MUFA), and top round muscles had significantly higher levels of C16:1n7, C18:1n7, C18:1n9, MUFA, MUFA/SFA. Loin muscle from the 3- and 12 mon-old groups had significantly higher scores for tenderness and overall likeness. Top round muscle from the 9- and 12 mon-old groups had significantly higher scores for overall likeness than those from the other age groups.