Neonatal Dairy Calves Research Articles

Parenteral Antimicrobial Treatment Diminishes Fecal Bifidobacterium Quantity but Has No Impact on Health in Neonatal Dairy Calves: Data From a Field Trial.

There is evidence that neonatal calves are over treated with antimicrobials that may disrupt colonization of their gastrointestinal tract (GIT) microbiota. The study objectives were to assess the decision-making process of antimicrobial use on a commercial dairy and impacts of parenteral antibiotics on dairy calves' GIT Bifidobacterium and calf health. Unhealthy pre-weaned dairy calves were enrolled based on farm personnel identification with age-matched healthy calves. Half the calves in each group were treated with a 3-day course of IM ampicillin and half were given supportive therapy as needed. Health scores (appetite, fecal consistency, attitude, and temperature) were recorded twice daily throughout the study. Because of inconsistency in employee health decisions, the 121 enrolled calves were reassessed using objective clinical observations plus fecal dry matter and placed into 1 of 3 health categories: healthy, uncomplicated diarrhea (bright attitude and good appetite but with diarrhea), and sick. Accounting for treatment group allocation, this resulted in six post-enrollment health and treatment categories. Calves were followed daily for 14 days post-enrollment and fecal samples collected at 6 time points and Bifidobacterium was quantified from these samples using quantitative PCR. The objective criteria for disease definition reclassified many “unhealthy” calves as uncomplicated diarrhea. Including all calves, on average, the quantity of Bifidobacterium decreased from the day of enrollment (median 8 days of age) across time to 14 days post-enrollment. Calves given an antibiotic the day of enrollment had a greater decrease in Bifidobacterium 4 and 9 days later relative to enrollment Bifidobacterium compared to untreated calves. At enrollment, sick calves and those categorized as uncomplicated diarrhea were more likely to have low Bifidobacterium counts and less likely to be categorized as healthy following antimicrobial treatment. Our results indicate that relying on farm personnel to identify morbidity may lead to some clinical misclassification. There was no indication that antimicrobials affected subsequent health outcomes, but antimicrobials did impact Bifidobacterium dynamics. These results highlight the importance and difficulty in assigning appropriate illness classification on farms and point to a need to develop better point of care diagnostics that improve calf husbandry and stewardship of antimicrobials.

Biochemistry and hematology reference intervals for neonatal dairy calves aged 5-12days.

Comprehensive hematology and biochemistry RIs are currently lacking in the literature for young dairy calves based on sample sizes more than 120. Young dairy calves are at a relatively high risk of poor health and welfare outcomes. They have a high risk of morbidity and mortality in the first 2weeks of life, and many are transported and fasted during this time. For example, non-replacement calves in Australia and New Zealand are usually 5-12days old when transported to abattoirs, meaning that calves of this age group are potentially at risk of both health and welfare compromise. Given these factors, sound, comprehensive, age-specific biochemical and hematologic RIs are needed for both veterinary clinical practice and to inform research on calf health and welfare. The aim of this study was to generate age-specific hematology and biochemistry RIs for dairy calves aged 5-12days. We collected blood samples from 141 fasted, healthy dairy calves on 10 Australian farms. Reference Value Advisor software was used to calculate nonparametric RIs for multiple biochemistry and hematology variables. RIs for a panel of hematology and biochemistry variables in dairy calves aged 5-12days old were derived. These RIs will be useful for clinical veterinary practice, as well as for research on dairy calf health and welfare.

Effects of colostrum management on transfer of passive immunity and the potential role of colostral bioactive components on neonatal calf development and metabolism

Neonatal dairy and beef calves are required to ingest adequate volumes of high-quality colostrum during their first hours of life to acquire transfer of passive immunity (TPI). As such, immunoglobulin G (IgG) has largely been the focus of colostrum research over recent decades. Yet, little is known about the additional bioactive compounds in colostrum that potentially influence newborn calf development and metabolism. The purpose of this narrative review is to synthesize research regarding the effects of colostrum management practices on TPI, as well as to address the potential role of additional colostral bioactive molecules, including oligosaccharides, fatty acids, insulin, and insulin-like growth factor-I, in promoting calf development and metabolism. Due to the importance of IgG in ensuring calf immunity and health, we review past research describing the process of colostrogenesis and dam factors influencing the concentrations of IgG in an effort to maximize TPI. We also address the transfer of additional bioactive compounds in colostrum and prepartum management and dam factors that influence their concentrations. Finally, we highlight key areas of future research for the scientific community to pursue to ultimately improve the health and welfare of neonatal dairy calves.

Effects of energy source in milk replacer on glucose metabolism of neonatal dairy calves

Milk replacers (MR) formulated to contain more lactose than whole milk could potentially reduce insulin sensitivity in dairy calves. This study evaluated how partially replacing lactose in MR with fat on a weight/weight basis affects glucose-insulin kinetics in neonatal dairy calves fed high quantities of MR. Thirty-four Holstein bull calves were blocked by dam parity (1.6 ± 0.3) and randomly assigned to 1 of 2 treatments (n = 17): a high-lactose MR (HL; 46.1% lactose, 18.0% crude fat, and 23.9% crude protein on a dry matter basis) or a high fat MR (HF; 39.9% lactose, 24.6% crude fat, and 24.0% crude protein on a dry matter basis). Calves were individually housed and fed pooled colostrum at 1.5 h and 12 h postnatal at 18 and 9% of metabolic body weight (BW0.75), respectively. From 24 h postnatal until the end of the study (d 7), calves were transitioned to MR (prepared at 150 g/L) at 18% of BW0.75 twice daily at 0700 and 1900 h. On d 4, an insulin-modified intravenous glucose tolerance test was conducted 8 h after the morning meal by intravenous infusion of glucose (0.54 g/kg of BW0.75, min 0) and insulin (3.9 µg/kg of BW0.75, min 20). During postprandial sampling on d 6, abomasal emptying was assessed by dosing acetaminophen (0.13 g/kg of BW0.75) with MR and measuring its appearance within plasma. Sequential blood samples were collected and analyzed for plasma glucose, insulin, and acetaminophen concentrations. Calves were killed on d 7 and liver and pancreatic tissues were collected for histomorphological analysis. Partially replacing lactose in MR with fat increased body weight gain (679.6 vs. 462.0 ± 69.68 g/d) and gain:metabolizable energy intake (186.6 vs. 120.5 ± 20.21 g of body weight/Mcal) compared with feeding HL MR. Furthermore, abomasal emptying rate was reduced in calves fed HF MR. Calculated variables based on postprandial glucose and insulin concentrations, such as maximum concentration or area under the curve, were or tended to be lower in HF than in HL calves. Postprandial insulin sensitivity tended to be reduced in HL compared with HF, although insulin sensitivity estimated from the insulin-modified intravenous glucose tolerance test was not different. Calves fed HF MR showed enhanced glucose-stimulated insulin secretion. In conclusion, partially replacing lactose in MR with fat resulted in smaller fluctuations in postprandial glucose and insulin concentrations and tended to increase postprandial but not fasting insulin sensitivity in neonatal dairy calves.

Oxidative Stress Compromises Lymphocyte Function in Neonatal Dairy Calves.

Dairy calves are unable to mount an effective immune response during their first weeks of life, which contributes to increased disease susceptibility during this period. Oxidative stress (OS) diminishes the immune cell capabilities of humans and adult cows, and dairy calves also experience OS during their first month of life. However, the impact that OS may have on neonatal calf immunity remains unexplored. Thus, we aimed to evaluate the impact of OS on newborn calf lymphocyte functions. For this, we conducted two experiments. First, we assessed the association of OS status throughout the first month of age and the circulating concentrations of the cytokines interferon-gamma (IFN-γ) and interleukin (IL) 4, as well as the expression of cytokine-encoding genes IFNG, IL2, IL4, and IL10 in peripheral mononuclear blood cells (PBMCs) of 12 calves. Subsequently, we isolated PBMCs from another 6 neonatal calves to investigate in vitro the effect of OS on immune responses in terms of activation of lymphocytes, cytokine expression, and antibody production following stimulation with phorbol 12-myristate 13-acetate or bovine herpesvirus-1. The results were compared statistically through mixed models. Calves exposed to high OS status in their first month of age showed higher concentrations of IL-4 and expression of IL4 and IL10 and lower concentrations of IFN-γ and expression of IFNG and IL2 than calves exposed to lower OS. In vitro, OS reduced lymphocyte activation, production of antibodies, and protein and gene expression of key cytokines. Collectively, our results demonstrate that OS can compromise some immune responses of newborn calves. Hence, further studies are needed to explore the mechanisms of how OS affects the different lymphocyte subsets and the potential of ameliorating OS in newborn calves as a strategy to augment the functional capacity of calf immune cells, as well as enhance calves’ resistance to infections.

Comparison of tests for failure of passive transfer in neonatal calf serum using total protein refractometry and the biuret method

Failure of passive transfer (FPT) is defined as failure to absorb colostral antibodies sufficient to achieve a serum Immunoglobulin G (IgG) concentration >10 g/L. Immunoglobulin G can be measured directly in calf serum using radial immunodiffusion (RID), or indirectly estimated by measuring total protein (TP). Indirect TP measures are usually favoured because of their relatively lower costs. The aim of this work was to compare TP measurements using refractometry and biuret methods against the reference RID test in neonatal dairy calves, and to assess agreement between these indirect measures. Neither the biuret nor the refractometer method provided a high sensitivity for detection of FPT, as defined by RID. There was no systematic difference between the methods in their estimation of TP, although the biuret method was more accurate than the refractometer method when tested against the reference RID test (accuracy = 83.1 % v 69.3 %) and the refractometer was more likely to overestimate the number of calves with FPT. Specificity for the biuret test was 93.9 % compared with the refractometer specificity of 74.4 %. Mean TP as estimated by the biuret method was higher than the mean TP estimated by the refractometer (6.25 g/dL versus 5.52 g/dL), and the Pearson correlation coefficient for the two assays was only moderate, at 0.58. This suggests that the biuret method is preferable to the refractometer for detecting FPT in calves, despite the superior convenience of the refractometer.

Supplementation of overripe pulp extract and green peel extract or powder of banana fruit peel (musa. cavendish) to diets of neonatal dairy calves: Effects on haematological, immunological and performance characteristics.

The present study investigated the effects of overripe pulp and green peel extract and powder of banana fruit (Musa. cavendish) on haematological, biochemical, immunological, health, and performance of Holstein dairy calves. In all, 40 newborn calves were randomly divided into four groups of 10 animals. In the control group, animals received no banana meal. In group 1, calves were supplemented with 2 g (dry matter)/kg body weight/day of overripe banana pulp extract. The calves in group 2 were supplemented with 1 g (dry matter) of overripe banana pulp extract/kg body weight/day and 1 g (dry matter) of green banana peel extract/kg body weight/day. The animals in group 3 were supplemented with 2 g/kg body weight/day of green banana peel powder. The feeding period of calves on the tested supplements was 5 days. Blood samples and other evaluations were taken on day 0 (at birth, before supplementation) and on days 7, 15 and 30. Just a trend towards better average daily weight gain was seen in groups 2 and 3 than others (p = 0.073). Significant group and sampling time interactions were seen for the quantities of RBC (group 1 was lower than other groups at day 30), MCV (group 3 was lower than other groups at day 30) and MCH (group 1 was higher than other groups at day 30) (p < 0.05). A trend towards significance in values of IgG (group 1 was lower than other groups at days 15 and 30) and bilirubin (higher values at day 7 in groups 1 and 2 than control, higher amounts at days 15 and 30 in groups 3 and 2 than control, respectively) was also observed. In conclusion, banana supplementation in neonatal calves had beneficial effects on the values of RBC, MCV, MCH, bilirubin, IgG and average daily weight gain in dairy calves.

Abstracts from the Proceedings of the 33rd Biennial Conference of the Australian Association of Animal Sciences

Encapsulated calcium butyrate (ECAB, ButiPEARL™, Kemin Industries, Inc. Des Moines, Iowa) is a novel and innovative feed technology developed to release butyrate continuously and slowly in the gastrointestinal tract of animals. Butyrate promotes rapid growth and development of rumen papillae for a better absorption of digested nutrients that enables dairy calves to transition smoothly from liquid milk to concentrates with minimal metabolic disorders (Pereira et al. 2017; Eckert et al. 2015; Ferreira & Bittar, 2011). This study investigated the effect of supplementing dairy heifer calves with ButiPEARL™ on average daily weight gain, liveweight and body conformation traits. The study was conducted using forty-eight newly born heifer calves (7 ± 0.4 days old; average liveweight 39.3 ± 5.3 kg) comprising purebred and crossbred Friesians, Jersey and Swedish Red. Calves were kept under the same pasture-based management system and utilised in a complete randomised experimental design for eleven weeks. The treatment groups included the Control (no supplementation), Low (4 kg/t) and High (6 kg/t) doses of ButiPEARL™. Feed intake, liveweight, average daily weight gain and body conformation parameters were subjected to a repeated measures general mixed model (proc mixed) analysis in SAS. Treatment diet, calf breed, dam parity, week of measurement and their first-order interactions fitted as fixed effects, while dam age was fitted as a random effect and all the initial body weight and conformation measurements fitted as covariates. Dose affected liveweight, average daily weight gain, chest girth, withers height, body length and body condition score (P < 0.05). The Low dose resulted in the highest average daily weight gain (0.83 ± 0.03 kg/day), heaviest liveweight (72.08 ± 1.6 kg), widest chest girth (95.94 ± 0.7 cm), longest body length (82.92 ± 0.6 cm) and best body condition score (1.99 ± 0.1; Table 1). Calves assigned to Control and High doses had similar liveweights (65.37 ± 1.4 kg vs 65.74 ± 1.5 kg), average daily weight gain (0.71 ± 0.0 kg vs 0.74 ± 0.0 kg) and chest girth (93.35 ± 0.7 cm vs 92.91 ± 0.7 cm; Table 1). These findings suggest that calf starter rations containing 4 kg/t ButiPEARLTM will improve overall liveweight and body conformation traits of newborn calves in a pasture-based system. Practical implications of supplementing neonatal dairy calves with ECAB is the potential to wean calves early and reduce age at first calving, which has been shown to result in improved lifetime performance. References Eckert E, Brown H, Leslie K, DeVries T, Steele M (2015) Journal of Dairy Science 98, 6315-6326. Ferreira L, Bittar C (2011) Animal 5, 239-245. Pereira GR, Barcellos JOJ, Sessim AG, Tarouco JU, Feijo FD, Neto JB, Prates ER, Canozzi MEA (2017) Revista Brasileira de Zootecnia. 46, 413-420.

Comparative Effects of Milk Containing A1 versus A2 β-Casein on Health, Growth and β-Casomorphin-7 Level in Plasma of Neonatal Dairy Calves.

Simple SummaryBovine milk generally contains two types of the milk protein β-casein, A1 and A2. Enzymatic digestion of the A1 type yields the opioid peptide β-casomorphin-7, which is suggested to adversely affect human and animal health. This study aimed to compare the effects of milk containing either homozygote A1 or A2 β-casein on health and growth parameters in 47 dairy calves during the first three weeks of life. Additionally, we studied, for the first time, the levels of intact β-casomorphin-7 in plasma of calves fed milk of alternative β-casein genotypes. Milk feeding of “A2-milk” led to a lower milk intake and a looser fecal consistency (higher prevalence of diarrhea) compared to “A1-milk”. Nevertheless, weight gains and end weights of calves of both feeding groups were similar, which might be caused by the associated higher protein content of milk containing the A2 variant. Intact β-casomorphin-7 was detected in plasma after A1- and A2-milk consumption, but was almost 5 times higher for A1-calves. In summary, A2-milk minimized the cleavage of the opioid peptide β-casomorphin-7 and might have advantages in the development of pre-weaned dairy calves.Research has shown that digestion of A1 β-casein (β-CN) affects gastrointestinal motility and opioid activity through the release of the peptide β-casomorphin-7 (β-CM7). In the case of the A2 variant, the cleavage of β-CM7 does not occur or occurs at a very low rate. Therefore, the aim of the study was to compare the effects of milk containing either homozygote A1 or A2 β-CN on health and growth parameters of dairy calves. Forty-seven neonatal calves (24 females, 23 males) of the breeds German Holstein (GH, n = 9), German Simmental (GS, n = 33) and their crossing (GH × GS, n = 5) were used in a 21-day feeding study. Fecal score (FS), respiratory frequency (RF), and rectal body temperature (BT) were recorded daily, whereas body weight was measured at birth and at day 21 to estimate the average daily weight gain (ADG). Additionally, blood was collected from calves three times during the experimental period and, for the first time, the respective plasma samples were analyzed for intact β-CM7. Consumption of A2-milk led to a lower daily milk intake (dMI) (p < 0.05). Furthermore, fecal consistency was softer for calves fed A2-milk (p < 0.05). Although 44% of A2-calves had diarrhea or revealed a tendency towards it (FS ≥ 3), A1-calves had a prevalence of 21%. Calves with a FS of 4 were offered an electrolyte solution and received a dietary food supplement for the stabilization of the fluid and electrolyte balance. Nevertheless, similar ADG and end weights (EW) of calves fed A1- or A2-milk (p > 0.05) indicate that A2-milk may compensate higher diarrhea rates and lower dMI due to the associated higher protein content. This is the first report of intact β-CM7 in plasma of calves fed milk of either A1 or A2 β-CN. Evidence from this study suggests that due to the change in the amino-acid sequence, A2-milk might be able to prevent or, at least, to minimize the cleavage of β-CM7 in calves.

PSVIII-5 Circulating serotonin (5-HT) concentrations are associated with failure of passive transfer in 3–5 day old dairy calves

Abstract Calf morbidity and mortality continues to be a challenge for the dairy industry and failure of passive transfer (FPT) is associated with an increased risk of disease. Serotonin (5-HT) has recently been implicated in the dairy calf immune system, but further work is needed to investigate the precise role of 5-HT in calf health. The objective of this study was to determine if 5-HT serum concentration at 3–5 days of age was associated with FPT. Blood samples were collected from 3–5 d old dairy calves (n = 418). Blood serum was assessed for FPT (serum protein &amp;lt; 5.5 g/dL) and analyzed using a commercial ELISA kit to determine circulating 5-HT concentrations. The mean (± SD) 5-HT concentration was 2574 (±1007) ng/mL. A logistic regression was used to determine if FPT (outcome; n = 124/418) was associated with 5-HT concentration (predictor; low &amp;lt; 2502 ng/mL, high= ≥ 2502 ng/mL). The model controlled for sex, breed (Holstein or Jersey), colostrum type (replacer or pasteurized), and dystocia (hard pull/surgical delivery). Sex, colostrum type, breed, and dystocia were not associated with FPT (P &amp;gt; 0.05). Calves with low serum 5-HT concentrations had a 2.7 (95% CI: 1.2–7.1) greater odds of having FPT compared to calves with high serum 5-HT concentrations (P = 0.04). Higher serum 5-HT concentrations were associated with successful passive transfer, but the causal pathway is unknown. Therefore, further investigation regarding 5-HT at different time points during calfhood should be explored as a potential way to reduce FPT in neonatal dairy calves.

Pharmacokinetics and Tissue Levels of Pantoprazole in Neonatal Calves After Intravenous Administration.

Background: Neonatal calves are at risk of developing abomasal ulceration, but there is a lack of pharmacokinetic data for potential anti-ulcerative therapies, such as pantoprazole, in ruminant species.Objective: The study objectives were to estimate plasma pharmacokinetic parameters for pantoprazole in neonatal dairy calves after intravenous (IV) administration. A secondary objective was to quantify the concentrations of pantoprazole in edible tissues after IV dosing.Methods: Pantoprazole was administered to 9 neonatal Holstein calves at a dose of 1 mg/kg IV. Plasma samples were collected over 24 h and analyzed via HPLC-MS for determining pantoprazole concentrations. Pharmacokinetic parameters were derived via non-compartmental analysis. Tissue samples were collected at 1, 3, and 5 days after administration and analyzed via HPLC-MS.Results: Following IV administration, plasma clearance, elimination half-life, and volume of distribution of pantoprazole were estimated at 4.46 mL/kg/min, 2.81 h, and 0.301 L/kg, respectively. The global extraction ratio was estimated at 0.053 ± 0.015. No pantoprazole was detected in the edible tissues 1, 3, or 5 days after administration. A metabolite, pantoprazole sulfone was detected in all the edible tissues 1 and 3 days after administration.Conclusion: The reported plasma clearance for pantoprazole is less than that reported for alpacas but higher than reported in foals. The elimination half-life in calves appears to be longer than observed in foals and alpacas. While pantoprazole sulfone was detected in the tissues after IV administration, further research is needed as to the metabolism and potential tissue accumulation of other pantoprazole metabolites in calves. Future pharmacodynamic studies are necessary to determine the efficacy of pantoprazole on abomasal acid suppression in calves.

Short communication: Molecular markers for epithelial cells across gastrointestinal tissues and fecal RNA in preweaning dairy calves

The objective of this study was to compare the transcription of gene markers for gastrointestinal (GI) epithelial cells, including fatty acid binding protein 2 (FABP2) and cytokeratin 8 (KRT8), and tight junction complex genes (TJP1, CLDN1, CLDN4) in fecal RNA against several GI tract tissue sections in dairy calves. Eight healthy Jersey calves were euthanized at 5 wk of age, and postmortem samples were collected from rumen, duodenum, jejunum, ileum, large intestine, cecum, and feces for total RNA isolation. Tissues and fecal samples were immediately frozen in liquid nitrogen until RNA isolation. A real-time quantitative PCR analysis was performed using a single standard curve composited of equal amounts of all samples, including cDNA from fecal and GI tract tissues. The mRNA expression of the tight junctions TJP1, CLDN1, and CLDN4 was greater in fecal RNA compared with lower GI tract tissues (i.e., duodenum, jejunum, ileum, large intestine, and cecum). Similar to fecal RNA, rumen tissue had greater expression of tight junctions CLDN1 and CLDN4 than lower GI tract tissues. Similarly, rumen tissue had greater expression of TPJ1 than all lower GI tract tissues except duodenum. The expression of TJP1 and CLDN4 was greater in fecal RNA than in rumen tissue; in contrast, CLDN1 mRNA expression was greater in rumen tissue than in the fecal RNA. The expression of FABP2 was greater in duodenum in comparison to all tissue except ileum. The mRNA expression of FABP2 in fecal samples was similar to jejunum and ileum. The expression of KRT8 in fecal samples was similar to duodenum, large intestine, and cecum. The fecal RNA had a greater expression of KRT8 in comparison to jejunum and ileum. The rumen tissue had the lowest mRNA expression of KRT8. The expression levels of FABP2, KRT8, and tight junction genes observed in fecal transcripts suggest that a considerable amount of RNA derived from GI tract epithelial cells can be detected in fecal RNA, which is in agreement with previous data in neonatal dairy calves and other biological models including humans, rodents, and primates. The greater expression of tight junctions in fecal RNA in comparison to sections of the low GI remains to be understood, and due to the importance of tight junctions in GI physiology, further clarification of this effect is warranted. The similarities in mRNA expression of FABP2 and KRT8 between fecal RNA and intestinal sections add up to the accumulating evidence that fecal RNA can be used to investigate molecular alterations in the GI tract of neonatal dairy calves. Further research in this area should include high-throughput transcriptomic analysis via RNA-seq to uncover novel molecular markers for specific sections of the GI tract of neonates.

The effect of meloxicam on neonatal dairy calves: Immunoglobulin G uptake and preweaning performance

Objectives of this study were to determine effects of meloxicam administered in 2 forms on IgG uptake, growth, and health of preweaned calves. Sixteen Holstein bulls and 14 heifers with a body weight (BW) of 44.3 ± 5.24 kg were blocked by birth date in a randomized complete block design. Calves were removed from the dam before suckling, weighed, and randomly assigned to 1 of 3 treatments: (1) colostrum replacer (CR) at 0 h with no meloxicam (control; CON), (2) 1 mg/kg of BW of meloxicam in pill form before CR (PL), or (3) 1 mg/kg of BW of meloxicam mixed in solution with CR (SL). Calves were fed 675 g of dry matter of CR, providing a volume of 3 L and 180 g of IgG. Blood samples were collected at 0 h to analyze initial IgG and ketone concentrations, and at 6, 12, 18, and 24 h to analyze IgG uptake. At 24 h, calves were fed 432 g of dry matter of 24% crude protein milk replacer (MR) split in 2 feedings, and free choice starter and water until 42 d. Weekly blood samples were analyzed for glucose, plasma urea nitrogen, and ketone concentrations. Time of consumption of MR, BW, length, hip and withers height, and heart girth were recorded weekly. All calves achieved adequate transfer of immunity. Meloxicam did not affect apparent efficiency of absorption, serum total protein, or IgG uptake at 6, 18, and 24 h; however, meloxicam-treated calves had lesser IgG concentrations at 12 h (24.40 and 22.59 g/L for PL and SL, respectively) compared with CON (28.47 g/L). Meloxicam treatment did not affect BW. Calves that received PL tended to gain length at a faster rate (0.24 cm/d) than those that received SL (0.19 cm/d). Meloxicam treatment did not affect MR intake, time of consumption of MR, total dry matter intake, or feed efficiency. Meloxicam-treated calves tended to consume more starter (560.4 and 515.4 g/d for PL and SL, respectively) than those that received CON (452.6 g/d). Ketone levels tended to be greater in meloxicam-treated calves (0.15 and 0.17 mmol/L for PL and SL, respectively), suggesting improved rumen development compared with those that received CON (0.12 mmol/L). Meloxicam treatment did not affect plasma urea nitrogen . Glucose concentrations of calves that received PL (73.2 mg/dL) were less than those that received SL (83.3 mg/dL). Results of this study suggest that meloxicam given at 0 h offers positive effects on starter intake, and possibly rumen development, of preweaned dairy calves. Treatment PL, as compared with SL, offered positive results for rumen development, indicated by lower blood glucose levels.

Dynamic Changes in Antimicrobial Resistance in Fecal Escherichia coli from Neonatal Dairy Calves: An Individual Follow-Up Study.

Simple SummaryAntimicrobial resistance in food animals is a global public health concern. In dairy farms, young calves typically carry high levels of antimicrobial-resistant (AMR) Escherichia coli, and may act as a potential reservoir. Fecal E. coli were isolated and tested for susceptibilities to eight common antimicrobials from 19 newborn dairy calves using individual follow-up at daily and weekly intervals. Shedding of AMR E. coli first appeared at 2–3 days after birth. The majority of fecal E. coli from neonatal calves (≤28 days old) were resistant to streptomycin, sulfisoxazole, and tetracycline. A tetracyclines-associated resistance gene (tetB) was predominant in the fecal E. coli from neonatal calves, and was also detected in maternal colostrum samples from the mothers of the tested calves. These results suggest the potential of antimicrobial resistance genes being shared between neonatal calves and their mothers’ colostrum. Neonatal calves with a history of treatment with ceftiofur also shed AMR E. coli resistant against beta-lactams. Moreover, these results provide new insights for controlling the spread of antimicrobial resistance on dairy farms.The prevalence of antimicrobial-resistant (AMR) Escherichia coli is typically higher in the feces of young dairy calves than in the feces of older cattle; however, the underlying factors contributing to this difference are poorly understood. In this study, AMR fecal E. coli from neonatal calves were characterized both at phenotypic and genotypic levels by individual follow-up sampling. Antimicrobial resistance profiles of E. coli isolates from the maternal colostrum were also determined. Most of the fecal AMR E. coli emerged in the calves at 2–3 days of age. The tetB was the most prevalent resistance gene detected among AMR fecal E. coli from <7-day-old calves, and was also detected in two isolates from the maternal colostrum. Weekly sampling revealed changes in the phenotype of AMR fecal E. coli as the calves aged. More than half of the fecal E. coli isolates acquired additional resistance to beta-lactams by 21–28 days of age, and minimum inhibitory concentrations were higher in ceftiofur-exposed calves than in unexposed calves. Our findings reveal the dynamic changes in AMR fecal E. coli from neonatal calves, and suggest that the feeding of colostrum and ceftiofur administration contribute to the higher prevalence of AMR E. coli in young dairy calves.

The Effects of administration of different parts of banana (Musa cavendish) fruit extracts and peel powder on the oxidative/antioxidative characteristics and some mineral concentrations in neonatal dairy calves

The present study examined the effects of overripe banana (Musa cavendish) pulp and green banana peel extract and powder on oxidants/antioxidants parameters and some minerals in Holstein dairy calves. Forty newborn calves were randomly divided into four groups of 10 (control, group one, group two and group three). The groups were homogenous for the parity of the dams and the time of birth.Within 12-48 hours of birth, calves were assigned to their treatment groups. In the control group, animals received no banana meal. In group one, calves were supplemented with 2 g (dry matter)/kg body weight/day of overripe banana pulp extract for five days. The calves in group two were supplemented with 1 g (dry matter) of overripe banana pulp extract /kg body weight/day and 1 g (dry matter) of green banana peel extract/kg body weight/day for five days. The animals in group three were supplemented with 2 g/kg body weight/day of green banana peel powder for five days. Blood samples were taken on day 0 (at birth) and on days 7, 15 and 30 through the jugular vein. Age (the time of sampling) had a significant effect on the values of phosphorous, potassium, iron, copper, FRAP and activity of GPx enzyme (p < 0.05). Significant group and sampling time interaction was seen for the FRAP concentrations (p < 0.05). In conclusion, banana supplementation in the Holstein dairy calf’s diet at the concentration and duration that was reported in the present study had beneficial effect on the values of FRAP.

Genetic Diversity of Cryptosporidium parvum in Neonatal Dairy Calves in Xinjiang, China.

Cryptosporidium parvum has been identified as a major cause of diarrhea and diarrhea-associated deaths in young children and neonatal calves. Infections can remain asymptomatic but may lead to malnutrition and persistent growth retardation. To assess the relationship between C. parvum genetic diversity and pathogenicity in neonatal dairy calves and determine the cause of diarrhea among these calves, 232 fecal samples from neonatal dairy calves on 12 farms in Xinjiang, China, were characterized for Cryptosporidium presence based on the small subunit rRNA gene. The Cryptosporidium prevalence was 38.4% (89/232), and three species were detected with restriction fragment length polymorphism analysis, including C. parvum (the significantly dominant species), C. ryanae, and C. bovis. Cryptosporidium prevalence was significantly higher in neonatal dairy calves with diarrhea (52.6%, 51/97) than in calves without diarrhea (28.1%, 38/135). All C. parvum-positive samples were analyzed based on the 60 KDa glycoprotein gene, and IIdA15G1, IIdA20G1, IIdA14G1, and IIdA19G1 were successfully subtyped. These data indicate that C. parvum may be a major contributor to diarrheal disease in neonatal dairy calves, and C. parvum subtypes from neonatal dairy calves in Xinjiang exhibited high genetic diversity.

Short communication: Colostrum versus formula: Effects on mRNA expression of genes related to branched-chain amino acid metabolism in neonatal dairy calves

The objective of the current study was to elucidate the effect of feeding colostrum or milk-based formula on the tissue mRNA abundance of the most relevant branched-chain amino acids (BCAA) transporters and catabolizing enzymes in newborn calves. German Holstein calves were fed either colostrum (COL; n = 7) or milk-based formula (FOR; n = 7) with comparable nutrient composition but lower contents of free BCAA, insulin, and insulin-like growth factor-I in the formula than in the respective colostrum for up to 4 d of life. Tissue samples from liver, kidney fat, 3 different muscles [M. longissimus dorsi (MLD), M. semitendinosus (MST), and M. masseter (MM)], as well as duodenum, jejunum, and ileum were collected following euthanasia on d 4 at 2 h after feeding. The plasma-free BCAA were analyzed, and the tissue abundance of solute carrier family 1 member 5 (SLC1A5), SLC7A5, and SLC38A2 as well as mitochondrial isoform of branched-chain aminotransferase (BCATm), branched-chain α-keto acid dehydrogenase E1α (BCKDHA), and branched-chain α-keto acid dehydrogenase E1β (BCKDHB) were assessed. The preprandial plasma concentrations of free BCAA were affected by time but did not differ between groups. The plasma concentrations of free BCAA decreased in COL, whereas they increased in FOR after feeding, resulting in higher postprandial plasma total BCAA concentrations in FOR than in COL. The mRNA abundances of BCATm, BCKDHA, BCKDHB, as well as BCAA transporters in the liver, were not affected by the diet. In kidney fat, the mRNA abundance of BCAA catabolizing enzymes did not differ between groups, but that of SLC1A5 was lower in FOR than in COL. The mRNA abundance of BCAA catabolizing enzymes in different sections of the small intestine was not affected by the diet, whereas that of SLC7A5 was or tended to be lower in the duodenum, proximal jejunum, and mid jejunum of the COL calves compared with the FOR calves. The mRNA abundance of BCKDHA was lower in MLD and MM but greater in MS for the FOR calves compared with the COL calves. The mRNA abundance of SLC7A5 in MST was lower in FOR than in COL, whereas it was unaffected by the diet in MLD and MM. The differential effect of feeding colostrum on the mRNA abundance of BCKDHA in 3 different muscle tissues might point to a muscle type-specific response. The results also indicate that the colostral BCAA might be favorably used for anabolic metabolism in the small intestine of neonatal calves. Such effects are speculated to be due to the stimulatory effects of growth factors and hormones present in colostrum.

Effect of the Source of Zinc on the Tissue Accumulation of Zinc and Jejunal Mucosal Zinc Transporter Expression in Holstein Dairy Calves.

Simple SummaryDiarrhea is the main cause of death in newborn calves and is associated with antibiotic use and economic loss for dairy farms. In this study, we evaluated the effects of different sources of the mineral zinc (zinc oxide (ZnO) and zinc methionine (Zn-Met)) on the growth, incidence of diarrhea, tissue zinc accumulation, gene expression of jejunal zinc transporters and serum concentrations of zinc-dependent proteins in newborn Holstein dairy calves. We found that Zn-Met supplementation promoted growth and reduced diarrhea from the second week after birth. It also increased the levels of zinc in the serum and liver, the level of the transporter protein ZIP4 in the jejunal mucosa, as well as the serum alkaline phosphatase and metallothionein concentrations compared to the control group. ZnO supplementation had similar but less marked effects to Zn-Met supplementation. These results suggest that Zn-Met supplementation may be an alternative to antibiotics for the treatment of newborn calf diarrhea.Zinc is considered to be an anti-diarrheal agent, and it may therefore reduce the incidence of diarrhea in young calves. In the present study, we aimed to compare the effect of zinc source on growth performance, the incidence of diarrhea, tissue zinc accumulation, the expression of zinc transporters, and the serum concentrations of zinc-dependent proteins in neonatal Holstein dairy calves. Eighteen male newborn Holstein dairy calves were fed milk and starter diet supplemented with or without 80 mg zinc/d in the form of Zn-Met or ZnO for 14 days, and were then euthanized. Zn-Met supplementation improved average daily gain and feed efficiency, and reduced the incidence of diarrhea, compared with control calves (p < 0.05). It also increased the serum and hepatic zinc concentrations and the mRNA expression of the ZIP4 transporter in the jejunal mucosa of the calves (p < 0.05). In addition, the serum alkaline phosphatase activity and metallothionein concentration were higher in Zn-Met-treated calves than in control calves (p < 0.05). ZnO supplementation had similar effects, but these did not reach significance. Thus, Zn-Met supplementation is an effective means of increasing tissue zinc accumulation and jejunal zinc absorption, and can be used as an anti-diarrheal strategy in neonatal calves.

Extended colostrum feeding for 2 weeks improves growth performance and reduces the susceptibility to diarrhea and pneumonia in neonatal Holstein dairy calves

The objective of this study was to determine the effect of partial replacement of whole milk with colostrum on the growth performance and health status of Holstein dairy calves. Neonatal heifer calves (n = 144; 2 d of age; 39.3 ± 0.82 kg of body weight, BW; mean ± SE) were assigned randomly to 3 groups with partial replacement of pasteurized whole milk with pasteurized colostrum at 0 (C0; 0 kg/d of colostrum + 5 kg/d of whole milk), 350 g (C350; 0.350 kg/d of colostrum + 4.650 kg/d of whole milk), or 700 g (C700; 0.700 kg/d of colostrum + 4.300 kg/d of whole milk) for 14 d; there were no refusals of liquid feed. From d 15 onward, the calves were fed with 5 kg/d of pasteurized whole milk, weaned on d 61, and monitored until d 81 of life. Throughout the study, the calves had free access to fresh clean water and calf starter. Partial replacement of whole milk with colostrum increased liquid feed dry matter intake (DMI) but decreased milk DMI; however, intakes of starter DMI, total DMI, metabolizable energy, crude protein, and ether extract were not affected by treatments. Overall, the C700 calves recorded greater weaning weight, final BW, heart girth change, feed efficiency, and average daily gain (ADG). The calves fed milk had a higher chance of having rectal temperature ≥39.4°C and general appearance score ≥2 compared with those receiving colostrum in their milk. Diarrhea was more prevalent in C0 versus C700 calves. The occurrence of pneumonia tended to be higher in milk-fed calves compared with C350 and C700 animals. Colostrum feeding resulted in fewer days with a rectal temperature ≥39.4°C, general appearance ≥2, diarrhea, and pneumonia. We computed Cliff's delta (effect sizes) of the extended colostrum feeding (C350 vs. C0, C700 vs. C0, and C700 vs. C350) on starter and milk DMI, ADG, BW, and feed efficiency. In C350 calves, the effect sizes (Cliff's delta) for milk DMI, ADG, BW, and feed efficiency were positive and small, but negative in C700 calves. Compared with C350 treatment, C700 treatment resulted in greater final BW with moderate effect size. Positive and moderate effects of feeding colostrum (C700 vs. C0) were observed on postweaning ADG and final BW. The findings showed that the inclusion of 700 g of colostrum in 5 kg of milk may be beneficial to the growth and health of dairy calves.

Effect of serum total protein concentration on early-life health and growth of dairy calves.

To assess the effect of serum total protein (STP) concentration on the early-life health and growth of dairy calves. 39,619 neonatal Holstein, Jersey, and crossbred calves from 15 dairy operations. Calves arrived at a single calf-raising facility at approximately 2 days old. Each calf was weighed at facility arrival, and a blood sample was obtained the next day for determination of STP concentration by refractometry. All calves were managed in a standard manner, and health events were recorded for 120 days. A subset of 3,214 calves was weighed at 120 days old, and the average daily gain (ADG) was calculated. Linear mixed models were used to assess the effect of STP concentration on specific health events. STP concentration was associated with the incidences of death, diarrhea, pneumonia, and whether a calf received IV fluid therapy. In general, the incidence of adverse health events decreased as STP concentration increased to 6.0 g/dL, plateaued at STP concentrations between 6.0 and 8.5 g/dL, and increased at STP concentrations > 8.5 g/dL. Although STP concentration was not associated with ADG, the ADG for Holsteins increased as STP concentration increased to 8.5 g/dL and then decreased at STP concentrations > 8.5 g/dL. Results suggested that, for neonatal dairy calves, an STP concentration between 6.0 and 8.5 g/dL was optimal for health and growth, and calves with an STP concentration < 5.0 or > 8.5 g/dL should be considered at high risk for adverse health events.