Friesian Calves Research Articles

Green Tea as a Supportive Treatment for Respiratory Disorders in Calves

Abstract: 90 Friesian calves belonging to Alexandria governorates, Egypt, included in this study and classified into 3 groups, group A: Consist of 20 apparently clinically healthy calves kept as a control, group B: contains 35 calves shows respiratory manifestation, treated with traditional therapy, group C: includes 35 calves exhibit signs of respiratory affection, treated with the same traditional drugs in addition to green tea extract (GTE). Complete early rapid recovery observed in group C than traditionally treated calves. Significant changes in serum creatinine and activity of AST and ALT were observed in group B and C in comparison with healthy calves. There were a significant decreases in the mean values of total antioxidant capacity, catalase activity, reduced glutathione (GSH), glutathione peroxidase (GSH-Px) activity and super oxide dismutase (SOD) activity in group B in comparing with control animals and group (C), while the same previously mentioned values showed a significant increase in group C in comparing with group A and B. On the other hand there is a significant increase and significant decrease in the activity of lipid peroxidase in group B and C, respectively when comparing with control group and with each other. The investigation revealed a significant decreases in the mean values of sodium and chloride with significant increase in potassium level in group B when compared with both control calves and group (C), while the same previously mentioned elements showed non-significant changes in group C when compared with the other two groups.

Growth of weaned Friesian bull calves on a herb sward or with concentrate supplementation during late summer and early autumn

ABSTRACTGrowth rates of weaned bull calves in late summer/early autumn can be low in a ryegrass/white clover-based system. This experiment compared the liveweight gain of weaned bull calves (n = 18 per treatment per year, in 3 replicates of 6 bulls) grazed on a herb sward comprised of chicory, plantain, red clover and white clover with bulls grazed on either pasture supplemented with 1.8 kg DM/day of concentrate, or pasture without supplementation. The experiment was repeated over three years. Bulls grazed on the herb sward grew faster (P < .05) than bulls grazed on pasture with or without concentrate supplementation. Liveweight gain of bulls grazed on pasture was less than for bulls supplemented with concentrate in two of the three years (P < .05). A herb sward is a better quality alternative to late summer/early autumn pasture, and could be used to increase liveweight gain of bulls during this period.

Bovine teeth as a novel matrix for the control of the food chain: liquid chromatography–tandem mass spectrometry detection of treatments with prednisolone, dexamethasone, estradiol, nandrolone and seven β2-agonists

ABSTRACTVeterinary drugs usually have rapid clearance rates in the liver and kidney, hampering their detection in conventional matrices such as the liver or urine. Pharmacological principles such as esterification may be applied to facilitate the administration of veterinary drugs and increase drug half-life. Prednisolone, whose therapeutic administration is regulated for food producing animals in the EU, is available in its acetate form as well as nandrolone, a banned anabolic steroid, which may be obtained as nandrolone phenylpropionate and estradiol as a benzoyl ester. While the distribution and accumulation of lipophilic and hydrophilic substances in human teeth have been well documented, studies on residues in bovine teeth are lacking. We hypothesised that analysis of bovine teeth could be used to detect both regulated and banned veterinary drugs. Steroids may be illegally used as growth promoters in food producing animals, alone or combined with β2-agonists; therefore, we developed, and validated, in accordance with the Commission Decision 2002/657/EC, two analytical confirmatory LC-MS/MS methods to detect these classes of compounds following a unique liquid extraction procedure. Finally, we analysed teeth from three male Friesian veal calves treated with intramuscular estradiol benzoate, oral prednisolone acetate or intramuscular nandrolone phenylpropionate in combination with oral ractopamine, respectively, and from seven bovines from the food chain. Teeth from treated animals were positive for their respective drugs, with the exception of nandrolone phenylpropionate. One sample from a food chain bovine was positive for isoxsuprine, one of the seven β2-agonists studied. Non-esterified forms of the steroids were not found. These results demonstrate that bovine teeth are a suitable matrix for the determination of pseudoendogenous substances or illicit administration of veterinary drugs.

Effect of Genetic Polymorphisms in GH/Hpa II and MSTN / Dra I Loci on Body Weight in Friesian Bull Calves.

The GH and MSTN gene polymorphisms and their association with body weight were declared in a population of 100 Friesian bull calves. For DNA extraction, collection of blood samples was carried out from the studied animals. The PCR for GH and MSTN genes yielded fragments of 329 and 1346 bp, respectively. The PCR-HpaII digestion of 329 bp of GH gene revealed three genotypes: AA genotype possess undigested fragment (329 bp), AB genotype has three fragments (329, 224 and 105 bp) and BB genotype has two fragments (224 and 105 bp). The GH genotypes incidence and alleles frequency were calculated. For the 100 Friesian bull calves, genotypic frequencies for the AA, AB and BB genotypes were 0.1, 0.78 and 0.12, respectively and the allele frequencies for A and B allele frequencies were 0.49 and 0.51. Statistical analysis revealed that there was a significant effect of GH genotypes on body weight. The AB genotype possessed higher body weight than the other 2 genotypes. Regarding MSTN gene, PCR-DraI digestion of 1346 bp fragment was monomorphic; where it yielded four fragments (505, 427, 321 and 93 bp) in all animals under study. The outcome of this study is that it highlights the effectiveness of GH/HpaII locus as candidate marker for body weight in cattle rather than MSTN/DraI.

Effects and costs of a strategic selective treatment for controlling ecto - and hemoparasitosis in Holstein Friesian calves

This work assessed the effectiveness and net operational costs of a strategic selective treatment for controlling ectoparasites (Rhipicephalus microplus, as well as Dermatobia hominis and Cochliomyia hominivorax larvae) and hemoparasites (Anaplasma marginale and Babesia spp.) in Holstein Friesian calves. Thirty calves were equally distributed in two groups: ST) strategic selective treatment and CT) conventional treatment. From birth, calves were monitored biweekly until 12 months of age. The CT group was subjected to parasite control according to directions provided by the veterinarian at the Experimental Farm of the Federal University of Lavras (FE/UFLA), whereas parasite control of the ST group followed criteria we had previously established. The ST group experienced fewer changes in physical traits on average and lower globular volume (GV) than the CT group (p &lt; 0.05). Approximately 23% of ST calves exhibited external omphalitis, compared with 48% CT calves (p &lt; 0.001). Additionally, ST calves were less affected than CT calves (p &lt; 0.05) by R. microplus females and D. hominis larvae. Seropositivity rates from the indirect immunofluorescence reaction for A. marginale and B. bovis were similar for both groups (ST: 85.6% and 87.8%, respectively; CT: 83.2% and 83.2%). Additionally, subclinical (asymptomatic infection) anaplasmosis predominated in both groups during the dry period of the year. The daily average weight gains (DWG) were identical among ST (580 g) and CT (570 g), but the effective operational cost (EOC) was 3.7 times greater in ST (R$ 406.58/animal) compared with CT (R$ 110.90/animal). Laboratory exams to monitor the animals represented the largest share of the cost (82.7%) in ST, whereas drug expenses represented the highest costs (49.8%) in CT. Despite having a greater EOC, ST was more efficient at reducing parasite burdens than CT. Calves in the former group presented fewer R. microplus or D. hominis, and experienced a lower percentage of hemolytic anemia (VG &lt; 24%). However, ST no affected the dynamic of A. marginale- and B. bovis-related infections, indicating that the FE/UFLA may be characterized as enzootically stable for these species.

Performance of crossbred dairy Friesian calves fed two levels ofSaccharomyces cerevisiae: intake, digestion, ruminal fermentation, blood parameters and faecal pathogenic bacteria

SUMMARYThe effect of feeding two levels ofSaccharomyces cerevisiaeon the performance of crossbred Friesian calves was investigated. Twenty-four neonatal male Friesian × Baladi calves (35·5 ± 0·25 kg of initial body weight) were randomly assigned in a completely randomized design into three experimental groups for 90 days (eight calves per group). Calves fed their diets without yeast (S. cerevisiae) were considered as Control, while the diets of other calves were supplemented daily either with 2·5 g (YL diet) or with 5 g (YH diet) of yeast per calf. Calves fed the YH diet showed increased feed intake, while dry matter and fibre digestibilities were increased in calves fed YH and YL diets. Calves fed YL and YH diets showed lower ruminal ammonia-N and higher total volatile fatty acids, acetate and propionate concentrations than Control calves. Both YH and YL calves showed increased plasma concentrations of total protein, globulin and glucose and decreased cholesterol and triglycerides concentrations. Calves’ final weight and daily gain were increased withS. cerevisiaeyeast supplemented diets. After 42 days of experiment,Clostridiumspp.,Escherichia coliandEnterobacteriaspp. counts were down to undetectable levels in the faeces of calves fedS. cerevisiaeadditive. It could be concluded that addingS. cerevisiaeto milk-fed calves increased feed utilization and improved pre-weaned calf performance and health status, reducing faecal pathogenic bacteria.

Comparison of immunoglobulin (IgG, IgM) concentrations in calvesraised under organic and conventional conditions

The objective of study was conducted on to compare immunoglobulin (Ig) concentrations in calves raised under organic and conventional conditions. 30 newborn Holstein Friesian calves (15 rose under organic and 15 under conventional conditions) in two dairy cattle farms. Blood samples were taken from 30 newborn calves at birth (before taking colostrum) and on 14th day to compare immunoglobulin (Ig) concentrations in calves raised under organic and conventional conditions. Furthermore, blood and colostrum samples were also taken from the mothers included into the study. IgG and IgM concentrations in colostrum and blood serums were determined using commercial ELISA kits. IgG concentrations at birth (0.79±0.34, 1.64±0.95 mg/mL) and on the 14th day (46.5±21.5, 70.5±27.8 mg/mL) in calves raised under organic conditions were lower than those raised under conventional conditions (p is less than 0.01). Calves raised under organic conditions also had lower IgM concentrations than calves raised under conventional conditions at birth (0.23±0.03 and 0.28±0.11 mg/mL, respectively) and on the 14th day (2.76±0.56 and 4,30±1.03 mg/mL, respectively) (p is less than 0.05, p is less than 0.01). IgG concentrations in the blood serum of cows raised under conventional conditions were higher than those raised under organic conditions (p is less than0.01), while no difference was found with respect to IgM concentrations (p&gt;0.05). No difference was found in the IgG and IgM concentrations of colostrum obtained from cows raised under organic and conventional conditions. In both the husbandry systems, positive and significant (p is less than0.01) correlations were found between the Ig concentrations of the mothers and offsprings. Consequently, it can be suggested that higher Ig concentrations in cattle raised under conventional conditions might be due to poorer environmental conditions.

Effect of plane of milk replacer intake and age on glucose and insulin kinetics and abomasal emptying in female Holstein Friesian dairy calves fed twice daily

The objective of this study was to investigate how preweaning plane of milk replacer intake and age can affect insulin and glucose kinetics as well as abomasal emptying rate in dairy calves fed twice a day. A total of 12 female Holstein Friesian calves were blocked by cow parity, paired by colostrum origin, and were randomly assigned to a high plane of milk replacer intake (8 L/d, 1.2kg of milk replacer/d; n=6) or a low plane of nutrition (4 L/d, 0.6kg of milk replacer/d; n=6). All calves received 4 L of colostrum over 2 meals (1 and 6h after birth) and were then directly transferred to their assigned feeding plans until they were stepped-down from milk by 50% during wk 7 and weaned on wk 8. Milk replacer (24% crude protein, 18% crude fat) was fed at 150g/L twice daily (0700 and 1700h) and all calves had ad libitum access to pelleted calf starter, chopped wheat straw, and water. Jugular catheters were placed in all calves at 4, 7, and 10wk of age. Then, postprandial response to plasma glucose, insulin, and acetaminophen (supplied with the meal) were determined to measure abomasal emptying. The next day, a glucose tolerance test was conducted by infusing glucose via the jugular catheter. At 4 and 7wk of age, the rate constant (%/h) for abomasal emptying of the meal was lower in high calves (0.21±0.02 in wk 4; 0.27±0.02 in wk 7) compared with low (0.34±0.02 in wk 4; 0.47±0.02 in wk 7). The postprandial plasma insulin area under the curve over 420min was greater in high calves (18,443±7,329; low=5,834±739 µU/mL) compared with low. We found no differences in glucose tolerance test kinetics between the high and low dairy calves at 4, 7, or 10wk of age. The findings from this study suggest that feeding dairy calves an elevated plane of nutrition in 2 meals of milk replacer per day does not decrease insulin sensitivity.

First report and histological features of Chlamydia pecorum encephalitis in calves in New Zealand

CASE HISTORY: Between September and October 2013, 40 of 150 crossbred Friesian dairy calves on a farm in the Manawatu region of New Zealand developed neurological signs when between 1 and 3 months of age. Calves were grazed in multiple mobs and calves from each mob were affected. A variable response was observed to initial treatment with thiamine, fluoroquinolone antibiotics and non-steroidal anti-inflammatory drugs.CLINICAL AND PATHOLOGICAL FINDINGS: Affected calves exhibited a range of neurological signs that included generalised depression, hind limb ataxia with a stiff gait, and knuckling of the fetlocks. In advanced cases, calves became recumbent with opisthotonous. Over a 4-week period, 13 calves died or were subject to euthanasia and a thorough necropsy was performed on three of these calves. Necropsy findings included fibrinous peritonitis, pleuritis and pericarditis, with no gross abnormalities visible in the brain or joints. Histology of the brain was possible in seven of the affected calves, with lesions ranging from lymphocytic and histiocytic vasculitis and meningoencephalitis, to extensive thrombosis and neutrophilic inflammation. Immunohistochemistry using an anti-chlamydial lipopolysaccharide antibody revealed positive immuno-staining in all seven cases, with no brain samples exhibiting immunostaining for Histophilus somni. DNA was extracted from a sample of fresh brain from one case and chlamydial DNA sequences were amplified by PCR and found to be identical to Chlamydia pecorum. PCR was also performed on formalin-fixed brain tissue from three of the other cases, but no chlamydial DNA was amplified.DIAGNOSIS: Chlamydia pecorum meningoencephalomyelitis (sporadic bovine encephalomyelitis).CLINICAL RELEVANCE: This is the first time that C. pecorum has been confirmed as a cause of clinical disease in New Zealand. Practitioners should be aware of this disease as a differential in calves with neurological signs, and submit samples of formalin-fixed brain as well as fresh brain to enable confirmation of suspected cases using PCR analysis. Furthermore, these cases illustrate that the histological lesions in the brains of calves with C. pecorum are more variable than previously reported, and pathologists should be aware that histological features may overlap with those traditionally ascribed to other organisms, such as H. somni.

HPLC-ESI-MS/MS assessment of the tetrahydro-metabolites of cortisol and cortisone in bovine urine: promising markers of dexamethasone and prednisolone treatment

ABSTRACTThe effects of long-term administration of low doses of dexamethasone (DX) and prednisolone (PL) on the metabolism of endogenous corticosteroids were investigated in veal calves. In addition to cortisol (F) and cortisone (E), whose interconversion is regulated by 11β-hydroxysteroid dehydrogenases (11βHSDs), special attention was paid to tetrahydrocortisol (THF), allo-tetrahydrocortisol (aTHF), tetrahydrocortisone (THE) and allo-tetrahydrocortisone (aTHE), which are produced from F and E by catalytic activity of 5α and 5β-reductases. A specifically developed HPLC-ESI-MS/MS method achieved the complete chromatographic separation of two pairs of diastereoisomers (THF/aTHF and THE/aTHE), which, with appropriate mass fragmentation patterns, provided an unambiguous conformation. The method was linear (r2 > 0.9905; 0.5–25 ng ml−1), with LOQQ of 0.5 ng ml−1. Recoveries were in range 75–114%, while matrix effects were minimal. The experimental study was carried out on three groups of male Friesian veal calves: group PL (n = 6, PL acetate 15 mg day–1 p.o. for 31 days); group DX (n = 5, 5 mg of estradiol (E2) i.m., weekly, and 0.4 mg day–1 of DX p.o. for 31 days) and a control group (n = 8). Urine was collected before, during (twice) and at the end of treatment. During PL administration, the tetrahydro-metabolite levels decreased gradually and remained low after the suspension of treatment. DX reduced urinary THF that persisted after the treatment, while THE levels decreased during the experiment, but rebounded substantially after the DX was withdrawn. Both DX and PL significantly interfered with the production of F and E, leading to their complete depletion. Taken together, the results demonstrate the influence of DX and PL administration on 11βHSD activity and their impact on dysfunction of the 5-reductase pathway. In conclusion, profiling tetrahydro-metabolites of F and E might serve as an alternative, indirect but reliable, non-invasive procedure for assessing the impact of synthetic glucocorticosteroids administration.

TaqI Polymorphism in MYF5 Gene and its Association with Body Weight in Friesian Bull Calves

TaqI Polymorphism in MYF5 Gene and its Association with Body Weight in Friesian Bull Calves

Suspected levamisole intoxication in calves

CASE HISTORY: A group of 32 Friesian and four Hereford calves, 3–4 months old with body weights between 100–120 kg, were purchased from a weaner sale. On arrival at the property the Hereford calves were treated with a combination anthelmintic containing 2 g/L abamectin and 80 g/L levamisole hydrochloride. Shortly afterwards they developed tremors and frothing from the mouth, and two died overnight. The Friesian calves were treated with the same anthelmintic on the following day, when some showed hypersalivation and frothing from the mouth.CLINICAL FINDINGS: Examination of the three most severely affected Friesian calves revealed severe nicotinic-type symptoms including hypersalivation, frothing from the mouth, muscle tremors, recumbency, rapid respiration, hyperaesthesia, and central nervous system depression. Other calves showed mild to moderate signs of intoxication including restlessness, tail switching, salivation, tremors, frequent defaecation, mild colic and jaw chomping. Two calves died shortly afterwards. An adverse drug event investigation revealed that the formulation and quality of the anthelmintic was within the correct specification, and that the drench gun was functioning correctly.DIAGNOSIS: Suspected levamisole intoxication due to a combination of possible overdosing, dehydration, and stress caused by transportation and prolonged yarding.CLINICAL RELEVANCE: Susceptibility to levamisole toxicity in New Zealand calves can be increased if factors like dehydration or stress are present. Levamisole has a narrow margin of safety, and overdosing in calves can easily occur if the dose rate is not based on their actual weight or health status.

Immunomodulatory properties of gamithromycin and ketoprofen in lipopolysaccharide-challenged calves with emphasis on the acute-phase response

Macrolide antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) have been reported to be modulators of the innate immune response, irrespectively of their antimicrobial and anti-inflammatory actions. Therefore, it was our objective to evaluate whether the macrolide gamithromycin (GAM) and the NSAID ketoprofen (KETO) attenuate the acute-phase response in calves, and whether their combined administration is beneficial due to synergistic and/or additive effects. To this end, both drugs, as well as their combination, were studied in a previously developed inflammation model, i.e., the induction of an acute-phase response by an intravenous lipopolysaccharide (LPS) challenge (0.5μg/kg body weight). Sixteen 4-week-old Holstein–Friesian calves were randomized into 4 groups: a positive control (+CONTR) group, receiving LPS but no pharmacological treatment (n=4) and a GAM (n=4), a KETO (n=4) and a GAM–KETO (n=4) group, receiving the respective drugs 1h prior to LPS administration. Clinical scoring and blood collection were performed at regular time points until 72h post LPS challenge. Plasma concentrations of the selected cytokines (tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6)), acute-phase protein (serum amyloid A (SAA)) and prostaglandin E2 (PGE2) were subsequently quantified. Pre-treatment with GAM had no effect in the inflammation model compared to the +CONTR group. KETO, on the other hand, completely inhibited depression, anorexia and fever. This remarkable influence was associated with a significant reduction of PGE2 synthesis by KETO, while the effect on TNF-α, IL-6 and SAA was not straightforward. The combined administration of GAM and KETO provided no synergistic or additive effects in this model, neither clinically nor regarding the studied inflammatory mediators. In conclusion, KETO entirely inhibited PGE2 synthesis, fever development and depression, while GAM did not exert any effect in this model. These results promote the concomitant use of an antimicrobial drug and a NSAID in the treatment of calf diseases associated with LPS, both to enhance clinical recovery and to improve animal welfare.

Effects of whole linseed and rumen-protected conjugated linoleic acid enriched diets on beef quality

Instrumental assessments and sensory tests were performed to evaluate the effects of diet and postmortem ageing time (1, 7 and 21 days) on beef quality. A total of 48 Friesian calves were randomly allocated to four dietary treatments: control, whole linseed (10% linseed), conjugated linoleic acid (CLA) (2% protected CLA), and whole linseed+CLA (10% linseed and 2% protected CLA). Animals were slaughtered at 458±16.6 kg live weight and 11 months of age. Ageing was more significant than diet on most instrumental parameters. Meat from linseed enriched diets had greater drip loss (P⩽0.001) and intramuscular fat (P⩽0.01) than meat from animals fed CLA. Beef aged for 7 and 21 days had lower cooking losses (P⩽0.01) and shear force (P⩽0.001) than beef aged for 1 day. Lightness was affected only by display time. The addition of CLA in the diet increased hue and yellowness, whereas the inclusion of linseed decreased these values, as well as increased redness. Linseed in the diet decreased fat odour (P⩽0.05), but increased beef (P⩽0.01) and liver (P⩽0.05) flavours. Meat aged for 21 days was significantly more rancid (P⩽0.001), even under vacuum storage. Several organoleptic properties were improved with the inclusion of linseed in the diet, whereas they remained unaffected by the inclusion of CLA.

EFFECT OF FLAXSEED OIL ON DIGESTIBILITY, BLOOD PARAMETERS, IMMUNO-RESPONSE AND PRODUCTIVE PERFORMANCE OF SUCKLING FRIESIAN CALVES

Aim of this study was to investigate the effect of flaxseed oil supplementation on the digestion, immunoglobulin concentration, some blood parameters, average daily gain, feed conversion and economic efficiency of suckling Friesian calves. A total of 28 newly born Friesian calves with weighing 31.42±1.9 kg were divided into two similar groups, 14 calves in each group. The first group (G1) was served as a control, while the second group (G2) was supplemented with 0.2 ml/kg LBW from flaxseed oil in suckling milk from birth up to weaning. Results showed that digestibility coefficients of DM, OM, CP, CF, EE and NFE and feeding values as TDN and DCP as well as feed intakes as TDN and DCP were higher (P<0.05) in G2 than in G1. Blood plasma immunoglobulins concentrations were higher (P<0.05) during different suckling intervalsin G2 than in G1. Red and white blood cells count, percentages of monocytes, neutrophils and package cell volume, and haemoglobin concentration increased (P<0.01) in G2 than in G1. Percentages of basophils, eosinophils and lymphocytes were not affected by supplementation. Concentration of total protein, albumin and globulin in plasma were increased (P<0.05-P<0.01), while, albumin to globulin ratio and concentration of total lipids, creatinine and urea-N concentrations decreased (P<0.01) in G2 than in G1. Plasma glucose concentrations and AST and ALT activities were nearly similar in both groups. Live body weight, average daily gain and feed conversion improved (P<0.001) in G2 than in G1. Economic efficiency was higher (P<0.05) in G2 than in G1. It could be concluded that flaxseed oil supplementation in milk of suckling Friesian calves (0.2 ml/kg LBW) during the suckling period improved growth performance and economic efficiencies as well as immune-response of Friesian calves without adversity effects on digestibility, haematological and biochemical parameters.

EFFECT OF THIAMIN OR NIACIN SUPPLEMENTATION INTO THE RATIONS OF GROWTH FATTENING CALVES ON THEIR PRODUCTIVE PERFORMANCE

This study aimed to evaluate the effect of feeding supplemented diets by two levels of thiamin or niacin on the productive performance of growing – fattening calves. A feeding trial was conducted using twenty five yearling Friesian calves of an initial weight ranged from 200 – 250 kg/head. Animals were divided into five similar groups (5 each) using the randomized complete block design. They were fed individually about 180 – d of an experimental period on a basal concentrate – roughage ration that consisted of approximately 56% concentrate feed mixture (CFM), 28% rice straw (RS) and 16% corn silage (CS), on DM basis, wherein T1 (control) had no supplement, T2 and T3 had 200 or 500 mg thiamin/h/d and T4 and T5 had 500 and 1000 mg niacin/h/d, respectively. Animals were fed according to NRC,(1984) standard for beef cattle. At the same time, five digestibility trial were conducted to determine the digestibility and feeding value of the experimental rations. Results indicated that digestion coefficients of DM and OM were insignificantly increased with all supplemented rations except that of high level – niacin ration (T5) which significantly increased, compared with control. Most nutrients digestibility were markedly improved by both supplements, the highest value (p<0.05) was occurred with the high level of niacin supplement (T5). Similar trend for the feeding values (TDN, DCP and DE) was found among dietary treatments. Showing the highest feeding value with (T5) total live body gain and daily gain were significantly increased due to both supplements (thiamin & niacin) and its levels, being 158.8, 187.6, 164.6, 167.6 and 188.8 kg total gain versus 882, 1042, 914, 931 and 1049/gm as daily gain for T1, T2, T3, T4 and T5, respectively. Feed conversion as DM: gain was slightly improved for calves fed rations whose supplemented by low level thiamin and both levels of niacin. Blood total protein and albumin concentrations were significant higher for all supplemental rations than those of unsupplemented one. Economically, the best net revenue was occurred with low thiamin and high niacin supplemented rations, being 12.10 and 12.70 LE /head/ day, respectively. The corresponding economical efficiency values were 112 and 114% based on control ration (100%). It cloud be concluded that using either thiamin or niacin as feed additive in ration formulation of growing and fattening Friesian calves tended to improve productive performance and economical efficiency for fattening calves, with the best results are associated with niacin supplement.

Study of the immunomodulatory properties of gamithromycin and dexamethasone in a lipopolysaccharide inflammation model in calves

The aim of this study was to define the in vivo immunomodulatory properties of the macrolide antibiotic gamithromycin in calves, with respect to the acute phase response. Additionally, the corticosteroid dexamethasone was included as a positive control immunomodulatory drug. Both drugs, as well as their combination, were studied in a previously developed inflammation model, which was initiated by an intravenous lipopolysaccharide (LPS) challenge (0.5μg/kg body weight). Twenty-four 4-week-old male Holstein Friesian calves were randomized into four groups: no pharmacological treatment (n=6) or a pharmacological treatment with gamithromycin (n=6), dexamethasone (n=6) or their combination (n=6) 1h prior to LPS administration. Blood collection and clinical scoring were performed at regular time points until 72h post LPS challenge. Plasma concentrations of selected cytokines (tumour necrosis factor-α (TNF-α) and interleukin 6 (IL-6)) and acute phase proteins (serum amyloid A and haptoglobin) were subsequently determined. Gamithromycin did not have any beneficial effect on the LPS-induced clinical signs (dyspnea, fever, anorexia and depression), nor on the studied inflammatory mediators. In the dexamethasone and combination groups, the occurrence of dyspnea and fever was not prominently influenced, although the calves recovered significantly faster from the challenge. Moreover, dexamethasone significantly inhibited the levels of TNF-α and IL-6, suggesting a key role for these cytokines in sickness behaviour. In conclusion, unlike dexamethasone, gamithromycin did not directly reduce cytokine release in an LPS inflammation model in calves.

Immunopathologic Changes in the Thymus of Calves Pre-infected with BVDV and Challenged with BHV-1.

The aim of this work was to investigate the effect of pre-infection with bovine viral diarrhoea virus (BVDV) on thymus immune cells from calves challenged with bovine herpesvirus 1 (BHV-1). Twelve Friesian calves, aged 8 to 9months, were inoculated with non-cytopathic BVDV-1. Ten of them were subsequently challenged with BHV-1 and euthanized in batches of two at 1, 2, 4, 7 or 14dpi with BHV-1. The other two calves were euthanized prior to the second inoculation and were used as BVDV-infected controls. A further 10 calves were inoculated solely with BHV-1 and euthanized at the same time points. Two calves were not inoculated with any agent and were used as negative controls. Quantitative changes in immune cells were evaluated with immunohistochemical methods to compare coinfected calves and calves challenged only with BHV-1. The results of this study pointed out BVDV as responsible for the thymic lesions observed in the experiment as well as for the majority of immunopathologic changes, including a downregulation of Foxp3 lymphocytes and TGFβ, which reverted as BVDV was cleared, and an overexpression of medullary CD8+ T cells. However, despite not inducing evident lesions in the thymus, BHV-1 seemed to prompt some immune alterations. Collectively, these data contribute to the knowledge on the immunopathologic alterations of the thymus during BVDV infections, and its importance in the development of secondary infections.

Ultrasonographic examination of the oesophageal groove reflex in young calves under various feeding conditions.

The oesophageal groove reflex was examined in 6 milk-fed Holstein Friesian calves once weekly during the first 17 weeks of life. Additionally, the effect of different feeding methods (bucket, different nipple positions and openings), different milk temperatures (20, 30, 39, 45°C) and milk replacer concentrations (100, 125, 150 grams/litre of water) on oesophageal groove closure was investigated. The reticulum and abomasum were examined ultrasonographically using a 5.0-MHz convex transducer before, during and after feeding, and the oesophageal groove reflex was considered to be functional when milk was seen entering the abomasum during feeding. The reflex was consistently induced throughout the study period in all calves at all examinations and under all experimental conditions. However, it should not be assumed that feeding technique can be neglected in unweaned calves because suboptimal feeding management has been linked to various digestive disorders.

Evaluation of Some Physical, Haemathological and Clinical Chemistry Parameters in Healthy Newborn Italian Holstein Calves

The aim of the present study was to investigate some physical, haematological and clinical chemistry parameters in the newborn Italian Holstein calf at birth and at 24 h of life, to evaluate changes during the immediate post-partum period. Forty-six Italian Holstein Friesian calves were included in this study. Heart rate, respiratory rate and body temperature were recorded at birth and at 24 h of life. The time needed to raise the head, acquire sternal recumbency, stand up were also recorded. Blood samples were collected before first feeding and at 24 h of age and CBC count, L-lactate, glucose and total protein concentrations were evaluated. The head was raised immediately in 46/46 calves, suckling reflex was acquired within 12±9 min, sternal position in 5±2 min and newborn stood up in 38±30 min. Some of the physical data, haematological and biochemical values showed statistical differences between birth and 24 h of age. The results from this study provide some information about physical and laboratory data of Italian Holstein Friesian calves, at birth and at 24 h of life. Our results confirm that several clinical and laboratory values in newborn calves differ from adult reference intervals and from calves of different breeds.