Lung and pleural lesions of veal calves at slaughter and their relationship with carcass weight

Summary

At slaughter the lungs of 2138 veal calves (13 transport groups, mainly from different farms) were examined. Lung and pleural lesions were classified by degree of extension and pathomorphological features, and the accompanying carcass weights were measured. Seventeen percent of the calves had extensive lung lesions, extensive pleural lesions or both, and their mean carcass weight was reduced by 4.3 kg (p<0.05). The percentage of calves with extensive lesions varied between transport groups from 4% to 33%. All pleural lesions were adhesive. Most lung lesions (93%) were classified as cuffing/exudative pneumonia. Slaughterhouse inspection of lungs can be used as a non‐clinical parameter of respiratory disease in veal calves.     

The relationship between clinical signs of respiratory system disorders and lung lesions at slaughter in veal calves

The presence and severity of lung lesions recorded post-mortem is commonly used as an indicator to assess the prevalence of respiratory problems in batches of bovines. In the context of a welfare monitoring based on on-farm measures, the recording of clinical signs on calves at the farm would be more convenient than the recording of lung lesions at slaughter. The aim of the present study was to investigate the relationship between clinical respiratory signs at farm and post-mortem analyses of lung lesions observed at slaughter in veal calves. If clinical signs were a good predictor of lung lesions it could be possible to integrate only those measures in a welfare monitoring system. One-hundred-and-seventy-four batches of calves were observed 3 times: at 3 and 13 weeks after arrival of the calves at the unit and at 2 weeks before slaughter. For each batch a maximum of 300 calves was observed and the proportions of calves showing abnormal breathing, nasal discharge and coughing were recorded. Post-mortem inspection was carried out on a sample of lungs belonging to calves from the observed batches. Each examined lung was classified according to a 4-point scale for pneumonia from healthy lung (score 0) to severe lesions (score 3). The clinical signs recorded infra vitam were significantly correlated with moderate and severe lung lesions for observations at 13 weeks and 2 weeks before slaughter and the level of the correlation was highly variable (r(sp) from 0.16 to 0.40). Receiver operating characteristic (ROC) curves were created and the area under the curves showed that batches with a high proportion of lungs with moderate or severe lesions could not be accurately detected by the three clinical signs of respiratory disorders. These results suggest that both clinical signs and post-mortem inspection of lung lesions must be included in a welfare monitoring schemes for veal calves.     

The influence of farmers' behavior on calves' reactions to transport and quality of veal meat

The relationships between farmers' behavior toward veal calves, calves' responses to handling and transport, and veal meat quality were assessed. Two groups of 10 veal units were selected based on previous observed farmers' behavior toward the calves: one group consisted of farmers who had shown predominantly "positive" behavior toward the calves, and the other group of farmers had shown predominantly "negative" behavior. Calves were observed for their reactions to people at the unit, and 20 calves per veal unit were transported either directly to the slaughterhouse or subjected to additional transport consisting of a supplementary 20-min transport with additional unloading and loading. The effort needed to load the calves onto the truck and their behavior during loading was observed. During loading and unloading, and during lairage at the slaughterhouse, potentially traumatic incidents (falling down, hits against structures, slips) were recorded, and heart rate and cortisol measurements were taken. Carcasses were evaluated on their weight, color, conformation, pH, and bruise level. A meat sample was taken from the longissimus thoracis muscle for physical, chemical, and sensory analysis. Calves originating from "positive behavior" units showed fewer fear responses to people at the veal unit, needed less effort to be loaded to the truck, had lower heart rates during loading and unloading, and had fewer incidents at the slaughterhouse than calves from "negative behavior" units (P < 0.05). Carcasses from calves from "positive behavior" units were paler, and analyses of the meat sample revealed lower pH, moisture level, and redness compared to carcasses from calves from "negative behavior" units (P < 0.05). Additional transport led to a lower cortisol level after transport and to higher carcass pH values at slaughter compared to direct transport (P < 0.05) but did not affect meat quality. We concluded that farmers' positive behavior toward veal calves during rearing is likely to reduce the emotional responses of calves to handling and transport and to lead to fewer incidents, compared to negative behavior. This reduction of calves' emotional responses seems to be the reason for improved veal meat color.     

Measurement of serum haptoglobin in neonatal farm-raised and bob veal calves using two immunoassay methods

Two immunoassays using an anti-bovine haptoglobin monoclonal antibody, Hap 1, were used to measure serum haptoglobin levels in neonatal farm-raised and bob veal calves. Bob veal calves were grouped into condemned, normal, and icteric groups based on the appearance of the carcass and viscera at postmortem examination. The competitive inhibition assay was more sensitive than the direct hemoglobin binding assay in detecting low levels of haptoglobin in all groups of calves. A significant number of bob veal calves with gross postmortem lesions other than icterus had detectable haptoglobin levels. The low levels of haptoglobin that were detected were not useful in distinguishing the relative severity of the inflammatory or degenerative process; however, the predictive values of a positive and negative test suggest haptoglobin measurement may be useful as a supplemental tool in evaluating the health status of the neonatal calf.     

Experimental Pasteurella multocida pneumonia in calves

Pasteurella multocida was isolated from the lungs of calves that died on a farm in the south of England. This organism was inoculated experimentally into 13 calves by the intratracheal route: in all but two of the calves mild clinical disease resulted and at necropsy, three or four days later, pneumonic consolidation involving up to 22 per cent of the lung was observed. P multocida was isolated from all but two of the lungs. Of two calves inoculated intravenously with P multocida, one showed mild clinical disease and slight pneumonic consolidation at necropsy and the other remained normal. Control calves inoculated intratracheally and intravenously with sterile broth showed no signs of illness and no pneumonic consolidation. Histologically the lung lesions comprised a fibrinous bronchopneumonia with variable sized areas of coagulative necrosis, extensive deposition of fibrin and massive dilatation and oedema of the interlobular and pleural lymphatics. It is concluded that P multocida should receive more recognition as a primary pathogen.     

The provision of solid feeds to veal calves: I. Growth performance, forestomach development, and carcass and meat quality

Growth performance, forestomach development, and carcass and meat quality of veal calves fed a milk replacer diet (Control) were compared to those obtained from calves fed the same liquid diet plus 250 g x calf(-1) x d(-1) of dried beet pulp or wheat straw. Three groups of 46 Polish Friesian calves, balanced according to initial BW, were assigned to the three dietary treatments in a fattening trial, which lasted 160 d. The provision of either solid feed did not affect the milk replacer intake. However, calves' ADG was increased (P < 0.01) only by feeding the beet pulp diet. The administration of both solid feeds improved calves' health status; calves fed solid feeds required fewer iron treatments for low hemoglobin and needed less medical treatments for respiratory or gastrointestinal diseases. In comparison to the Control calves, the provision of wheat straw and beet pulp increased iron intake throughout the fattening period by 41 and 130%, respectively. However, only calves fed beet pulp showed higher levels of hemoglobin and plasma iron concentrations (P < 0.05), whereas the same blood parameters were similar between Control calves and those fed wheat straw. At slaughter, both solid feeds led to empty forestomach weights heavier than those of Controls without reducing dressing percentage. The reticulorumen was heaviest in calves fed beet pulp, whereas wheat straw promoted omasal development. The administration of beet pulp resulted in a better carcass conformation than did the Control diet or wheat straw, but it had a detrimental effect on carcass color, which was graded as the darkest (P < 0.001). Consistent with this result, meat color of calves fed beet pulp was darker than that of Control calves and those fed wheat straw, because of the higher hematin concentration measured at the muscle level. No differences in carcass and meat color were observed between Control calves and calves fed wheat straw. The administration of solid feeds for welfare purposes does not always prevent the production of veal meat fulfilling the color standards required by the market. There is not a straight-forward relationship between a solid feed's iron content and the "redness" of veal meat, which should be related to the capability of the calves to use the iron provided by the roughage.     

Health of finishing steers: effects on performance, carcass traits, and meat tenderness

The impact of respiratory disease during a 150-d feedlot finishing period on daily gain, carcass traits, and longissimus tenderness was measured using 204 steer calves. Feedlot health status was monitored in two ways. First, clinical signs of respiratory infection were evaluated each day; treatment with antibiotic was based on degree of fever (if rectal temperature exceeded 40 degrees C then calves were treated). Steers that were treated (n = 102) had lower (P<.05) final live weights, ADG, hot carcass weights (HCW), less external and internal fat, and more desirable yield grades. Steers that were treated had a higher prevalence of carcasses that graded U.S. Standard than steers that were never treated. Second, as an alternative index of health status, lungs of all steers were evaluated at the processing plant using a respiratory tract lesion classification system; this health index included presence or absence of preexisting pneumonic lesions in the anterioventral lobes plus activity of the bronchial lymph nodes (inactive vs active). Lung lesions were present in 33% of all lungs and were distributed almost equally between treated (37%) and untreated cattle (29%). Steers with lesions (n = 87) had lower (P<.05) daily gains, lighter HCW, less internal fat, and lower marbling scores than steers without lesions. Compared to steers with lesions but inactive bronchial lymph nodes (n = 78), steers with lung lesions plus active lymph nodes had lower (P<.01) ADG and dressing percentage. Longissimus shear force values for steaks aged 7 d were lower (P = .05) from steers without lung lesions than those for steaks from steers with lung lesions. Overall, morbidity suppressed daily gains and increased the percentage of U.S. Standard carcasses. Compared to health assessment by clinical appraisal (based on elevated body temperature), classification based on respiratory tract lesions at slaughter proved more reliable statistically and, thereby, more predictive of adverse effects of morbidity on production and meat tenderness.     

Effects of the provision of large amounts of solid feeds to veal calves on growth and slaughter performance and intravitam and postmortem welfare indicators

Polish Friesian male calves (n = 78) were used to investigate the effects of innovative feeding plans based on the provision of large amounts of solid feeds on growth performance, welfare, and carcass characteristics of veal calves. Groups of calves (initial BW 71.5 ± 3.7 kg) were fed 1 of 3 treatments (26 calves/treatment): 1) milk replacer plus corn grain (CG), 2) milk replacer plus an 80:20 mixture (as-fed basis) of corn grain and wheat straw (CGS), or 3) milk replacer plus a 72:20:8 mixture (as-fed basis) of corn grain, wheat straw, and extruded soybean, respectively (CGSES). All the treatments provided at least 170 kg DM/calf from solid feed throughout the 206 d of fattening. Type and concentration of milk replacer were the same for all calves throughout fattening. Calves fed CGSES received 96% of the daily amount of milk replacer delivered to CG and CGS to balance the dietary CP content. No differences (P ≥ 0.063) among treatments were observed for growth performance and DMI. Health status of CG calves was less than CGSES calves, as indicated by the greatest (P < 0.001) proportion of milk replacer refusal events and the greatest (P < 0.001) incidence of treatments for respiratory disorders. Inclusion of straw and soybean in the solid feeds increased (P < 0.001) the daily intake of iron in CGS and CGSES as compared with CG; however, blood hemoglobin concentrations measured at d 5 and 31 were greater (P < 0.05) than when measured on d 80, 122, and 206 of fattening. Feeding treatment did not (P ≥ 0.107) affect HCW, dressing percentage, or carcass color. Calves fed CG had heavier (P < 0.001) reticulorumens and more (P < 0.001) developed rumens than CGS and CGSES calves, but 84% and 68% of CG rumens (P < 0.001) showed overt signs of hyperkeratinization and plaques, respectively. These alterations of rumen mucosa were not detected in CGSES calves, and only 8% of CGS calves had rumen plaques. Regardless of feeding treatment, postmortem inspection recorded a prevalence of more than 84% abomasal lesions. When feeding veal calves with large amounts of solids, it is advisable to avoid the provision of corn grain alone and replace part of the cereal with a roughage source to improve calf health and prevent rumen mucosa alterations.     

Breeding for veal production in black and white dairy cattle

In 1983 a field trial was conducted to rear progeny of performance tested Black and White bulls with 0–100% Holstein Friesian (HF) genes as veal calves. The purpose was to establish the relationship between performance test traits of sires and veal production traits of their progeny, to estimate genetic parameters for veal production and to study the possibilities of selection for veal production.In total 1060 progeny of 55 performance tested bulls were reared, in a specialised rearing unit, to an average live weight of 208 kg with about 300 kg milk replacer per head. Heritabilities were estimated after correction for month of supply and proportion of HF genes of sires and dams. Heritabilities for weight, type score and price at the start were 0.34, 0.29 and 0.19, respectively. Estimates for daily gain, feed conversion and carcass traits varied between 0.45 and 0.62. The net value of the calves, which was calculated as carcass value minus costs during rearing, showed a heritability of 0.44 and a genetic variation of Dfl. 71.00. This indicates that selection for veal production might be effective.No significant relationship could be detected between the performance test in Black and Whites on a roughage diet, and the progeny test for daily gain and feed conversion on a milk replacer diet. This implies that present methods of performance testing are not effective in improving veal production. Index calculations demonstrated that recording the pedigree on the farm at birth and sampling slaughter data, i.e. carcass weight and score for fleshiness of 50 progeny per sire, may be an effective procedure to obtain a reliable breeding value estimate or sires for veal production.     

Use of treatment records and lung lesion scoring to estimate the effect of respiratory disease on growth during early and late finishing periods in South African feedlot cattle

Growth, morbidity, and slaughter data from 2,036 calves in 2 South African feedlots were used to estimate the effect of bovine respiratory disease (BRD) and of lung lesion type and extent on growth during the early (processing to d 35) and late (d 35 to slaughter) finishing periods. Calves were weighed at processing (d 5 after arrival), on d 35, and at slaughter after a mean of 137 d on feed. All calves were monitored twice daily and were treated for BRD if rectal temperature was > 40 degrees C or if other specific signs of BRD were present. After slaughter, the occurrence and extent of parenchymal bronchopneumonic lesions and pleural adhesions were recorded. Subclinical BRD (never treated but with lung lesions at slaughter) occurred in 29.7% and clinical BRD in 22.6% of calves. Lung lesions were present in 43% of calves at slaughter; 8.6% had parenchymal lesions and 38.8% had pleural adhesions. Using a combined case definition (treated for BRD and/or lung lesions present at slaughter), the incidence of BRD was 52.5%. During the early finishing period, clinical BRD reduced ADG by 216 g (P < 0.001), subclinical BRD reduced ADG by 91 g (P < 0.001), and the combined effect of BRD was a 143 g reduction in ADG (P < 0.001). After d 35, animals treated for BRD tended to grow faster than those with subclinical BRD (P = 0.11), indicating that treatment was generally successful in reducing economic losses. The extent of bronchopneumonic lesions at slaughter was not associated with reduced growth during the early finishing period (P = 0.27), but extensive lesions reduced ADG by 88 g during the late period (P = 0.02). In contrast, the extent of pleural adhesions was not associated with reduced growth rate during the late finishing period (P = 0.37) but was strongly associated with reduced ADG before d 35; there was a 101 g reduction (P < 0.001) and a 220 g reduction (P = 0.01) for adhesions involving < 50% and > 50% of the pleural surfaces, respectively. Thus, although the presence of bronchopneumonic lesions and pleural adhesions at slaughter were both associated with reductions in overall ADG, they were indicative of production losses having occurred at different times during the finishing period. The overall effect of BRD was a 24 g reduction in ADG (P = 0.02) and a 5.1 d increase in days on feed (P < 0.001). The hidden cost of reduced growth rate due to BRD amounted to $3.41 per calf with clinical or subclinical BRD, or $1.79 per animal entering the feedlot.     

Some aspects of the gastrointestinal microflora of veal calves fed different rations: a pilot study

The gastrointestinal microflora of veal calves reared on different diets was studied because the nature of this microflora affects the quality of veal as a result of contamination of carcass surfaces with intestinal contents during slaughter. Diet A consisted of a milk substitute, diet B of milk substitute + straw pellets and diet C of milk substitute + straw pellets + concentrates. In the rumen fluid of calves reared on diet A significantly higher counts of Gram-negative bacteria but lower counts of thermotrophic enterobacteriaceae were found than in calves reared on diets B or C. As for the faecal flora, diets B and C seem to result in significantly lower counts of Gram-negative bacteria and thermotrophic enterobacteriaceae. In 46% of the faecal specimens and 62% of the specimens of rumen fluid from calves fed on milk substitute only, Pseudomonas aeruginosa was isolated in mean counts of 4.1 log cfu/g and 5.2 log cfu/g respectively. P. aeruginosa could not be isolated from any specimen from calves receiving straw pellets. These results indicate that the inclusion of straw pellets in the diet of veal calves may increase the bacteriological safety and keeping quality of veal.     

Experimental Bovine Pneumonic Pasteurellosis II. Genesis and Prevention

Two experiments were conducted. In the first, 16 crossbred Hereford calves were divided into two equal groups. The first group was vaccinated intranasally with a commercial vaccine against bovid herpesvirus 1 and the second group was unvaccinated. The calves were later exposed to an aerosol of bovid herpesvirus 1 (strain 108) for five minutes. Four calves from each group were subjected to transportation and four calves from each group were kept in an environmental chamber for four days. Four days after viral aerosol all calves were exposed to an aerosol of Pasteurella haemolytica and the same subgroups were again transported or held in the chamber for a further four days.

The calves that did not die from pneumonia were necropsied ten days after the final day of transport. Pulmonary lesions were present in both vaccinated and control animals but were less extensive in the vaccinated calves. Six of eight vaccinated but none of the eight control calves survived.

In the second experiment, eight crossbred Hereford calves were divided into two equal groups. One group was vaccinated with bovid herpesvirus 1 (strain 108) and the other acted as controls. Four weeks later all calves were sequentially exposed to aerosols of bovid herpesvirus 1 (strain 108) and P. haemolytica four days apart. Three of the four controls but none of the vaccinates died from pneumonia. Every lobe of the lungs in all the controls was affected by pneumonia while no pulmonary lesions were found in the vaccinated calves. The differences in efficacy of the modes of vaccination and the possible role of transport stress are discussed.

     

Relationships between counts of nasopharyngeal bacteria, temperature, humidity and lung lesions in veal calves

Nasopharyngeal swabs were taken from four groups of veal calves at intervals throughout their growth and the aerobic bacteria cultivated from the swabs counted. The calves were kept under three different husbandry systems; naturally ventilated straw-yards, fan-ventilated crates and crates with a controlled climate. The numbers of bacteria isolated varied in a complex manner; however, in one group of calves a significant proportion (P less than 0.01) of the variation in weekly bacterial counts was associated with the changes in vapour pressure and temperature which took place between two and four days previously. In calves kept at a constant temperature of 16 degrees C, the bacterial populations in the nasopharynx were at a minimum between 65 and 75 per cent relative humidity and tended to rise at humidities outside this range. There was a temporal relationship between nasopharyngeal bacteria and lung lesions. In three groups the numbers of bacteria in calves at nine weeks old were positively correlated (P less than 0.05) with lung damage observable at 16 to 18 weeks old.     

Cilia-Associated Respiratory (CAR) bacillus infection in veal calves and adult cattle

Cilia-Associated Respiratory (CAR) bacillus is a filamentous bacterium that colonizes the ciliated epithelium of the respiratory tract of many animal species and that has been associated with chronic inflammatory lesions in naturally and experimentally infected rats, mice and rabbits. In the present study, the prevalence of CAR bacillus infection and histological lesions of the trachea in veal calf and adult cattle were investigated. Forty five healthy veal calves and 45 adult cattle, raised in 18 different herds were selected at slaughter. From each animal, a tracheal sample was processed for histology, stain-ed with the Warthin-Starry method to evaluate the presence of CAR bacillus, and with haematoxylin and eosin to evaluate the presence of inflammatory lesions. CAR bacillus was identified in 17 veal calves (37.7%) and in 7 adult cattle (15.5%). Inflammatory lesions were found in 42 veal calves (93.3%) and in 41 adult cattle (91.1%). Statistical analysis pointed out a significant correlation between the presence and number of CAR bacilli and the presence and number of lymphoid follicles (P = 0.0071) and the presence and severity of neutrophilic infiltrates (P = 0.0428). These results indicate that CAR bacillus infection is common in cattle and is correlated with tracheal inflammatory lesions.     

Pathogenesis of naturally acquired bovine respiratory syncytial virus infection in calves: morphologic and serologic findings

Lesions in 32 calves that died or were euthanatized during the course of severe natural infection with bovine respiratory syncytial virus (BRSV) are described. All calves had been dyspneic for 1 to 2 days. At necropsy, lesions that could be related to dyspnea included congested and cyanotic mucosae and widespread petechiae. The lungs had various lesions in the cranioventral (CV) and caudodorsal (CD) portions. The CV portion of the lungs was consolidated, firm, and edematous. Histologically, the main characteristic was degenerative, necrotic bronchiolitis, with few syncytial cells. Signs of repair, such as epithelial hyperplasia, fibrosis, and bronchiolitis obliterans, often were observed. The CD portion of the lungs was markedly distended, owing to severe edema and emphysema. Bronchiolar lesions were lacking in the CD portion. In 14 calves, hyaline membranes were seen in the CV and CD portions. Results of immunofluorescence for BRSV were positive in 24 calves, but only in the CV portion of the lungs. The calves had variable concentrations of BRSV-specific IgG1 and IgM in serum, lung lavage fluid, or both. The BRSV-specific IgA, on the contrary, was seldom detected. Thus, 2 discrepancies existed. Although the clinical picture appeared to be acute, bronchiolar lesions and serotest results suggested infection of longer duration. Also, although virus and viral cytopathologic features were detected only in the CV portion of the lungs, the CD portion had extensive lesions that consisted of emphysema and edema.     

Antibiotic and sulfonamide residues from Food Safety Inspection Service bob veal calf tissues by region, from October 1987 to September 1988

Of 3,095 bob veal carcasses declared positive to the calf antibiotic and sulfonamide test (CAST) performed by USDA-FSIS personnel during the fiscal year 1988, 967 were submitted to USDA-FSIS laboratories for intensified antimicrobial evaluation of kidney, liver, and muscle specimens. In the western region, CAST-positive specimens were analyzed from certified calves, that is, calves declared free of antimicrobials by their producers. In the midwestern and eastern regions, 20% of the CAST-positive carcass submissions were certified and 20% had not been certified. Among the regions, neomycin was the most commonly reported agent from kidney specimens; however, there were some distinct differences among regions (24.6% of the specimens in the Midwest, 37.4% in the East, and 46.8% in the West). Reports of gentamicin in specimens also were different among regional laboratories (9.0% in the Midwest, 12.1% in the East, 3.1% in the West). Sulfamethazine was less frequently reported by the western laboratory, never exceeding 2% among the 3 tissues tested, whereas the eastern and midwestern laboratories had at least 1 tissue type that was greater than or equal to 9%. Not all specimens were subjected to sulfonamide evaluation. Regional patterns were noticed for unidentified microbial inhibitors, which were most evident for liver in which 24.6% of the specimens at the western laboratory were classified as having unidentified microbial inhibitors, and only 6.3% of specimens at the eastern laboratory were classified as having unidentified microbial inhibitors.     

The impact of gentle contacts on ease of handling, welfare, and growth of calves and on quality of veal meat

It has been demonstrated previously that regularly stroking and letting calves suck fingers leads to less avoidance and more approach behavior of the calves toward people. To examine whether these positive contacts affect the welfare and productivity of calves and the quality of veal meat we used 22 veal calves housed in individual crates. Half of them received minimal contact with the stockperson (controls), and the other half were given additional gentle contacts around meals, by stroking the calves and allowing them to suck the stockperson's fingers, during the entire fattening period (21 wk). Welfare was assessed through behavioral reactivity (reactions to handling, to surprise stimuli, and to novelty), neuroendocrine responses to stress (cortisol in response to an ACTH challenge, catecholamine-synthesizing enzymes), and health (number of medical treatments, abomasal lesions). Calf productivity was assessed through growth rates and meat quality through glycolytic potential (an estimator of resting glycogen level in muscle), pH, and color. Calves that received gentle contacts were less agitated (P < .01) and tended to defecate less (P = .08) when handled in a cart on wheels than the control calves, but no treatment effects were found in reactivity to novelty and surprise stimuli, responses to ACTH, and catecholamine synthetic potential. Calves given gentle contacts had fewer abomasal lesions than controls (0/11 vs 4/11, P = .05). The glycolytic potential of the semimembranosus muscle was higher in calves that received gentle contacts than in controls (172.6 vs 154.1 micromol/g, P < .05), but no treatment effects were observed on meat pH, meat color, or growth rates. It is concluded that gentling veal calves reduces their reactions to handling. Gentle contacts reduce the reaction to transport shown by differences in glycolytic potential. In addition, the reduction in reactions to handling and the decreased incidence of abomasal lesions can contribute to an improvement of the calves' welfare.     

Effects of Phyto-Oestrogens on Veal Calf Prostate Histology

In veal calf production plant-based proteins are frequently included in milk replacer fed to the animals. Since soy products, which are mostly used, are known for their high levels of phyto-oestrogens, the effects of these feeds on the veal calf prostate were examined. Goal was to determine whether these compounds could interfere with histological screening for oestrogenic growth promoters. In a feeding experiment, four groups of veal calves fed plant-based protein-supplemented milk replacer (PBM), containing 5% soy concentrate, 5% soy isolate, 5% wheat gluten and 2% potato protein, for 4 weeks were compared to animals fed dairy-based control feed (DBM); animals treated with estradiol benzoate, diethylstilbestrol and ethinylestradiol served as positive controls. Daidzein and genistein levels measured in feed and urine showed high levels of genistein and daidzein in the soy isolate and soy concentrate supplemented feeds. Genistein and daidzein were also found in the urine of the animals that were fed these feeds. Haematoxylin–eosin-stained prostate sections of PBM-fed animals showed slight hyperplasia and some dilated tubules as compared to the DBM-fed group, but no metaplasia, which is used for screening for oestrogenic hormones. The positive controls showed extensive squamous metaplasia. Immunohistochemical staining for cytokeratin 5 (using RCK 103 monoclonal antibody) in basal cells showed a normal staining pattern of basal cells in the DBM-fed calves and extensive basal cell proliferation and squamous metaplasia in the oestrogen-treated positive control animals. PBM-fed calves showed no increase of basal cell staining but showed elongations of the basal cells in most animals, sometimes resulting in circular figures. It is concluded that the feeds examined in this study did not interfere with histological screening for oestrogens in male veal calves.     

Implant sequence effects in intact male Holstein veal calves: carcass characteristics

Seven sequences of growth promotant implants were used in intact male Holstein veal calves (n = 443). Implants were administered on d 0 (within 4 d after arrival at the veal barn), 42, and 84. The implants used were placebo (0), Z (36 mg zeranol), ET (20 mg estradiol, 200 mg testosterone), EP/2 (10 mg estradiol, 100 mg progesterone), EP (20 mg estradiol, 200 mg progesterone), and EBA (24 mg estradiol, 120 mg trenbolone acetate). The following sequences were compared: 0-0-0 (negative control), 0-ET-ET, Z-ET-ET, 0-EP-EP, Z-EP-EP, 0-EP/2-EBA, and Z-0-EBA. Sequences 0-EP-EP, Z-EP-EP, and 0-EP/2-EBA increased (P<.05) carcass weight from 3.3 to 3.9% compared to nonimplanted controls. There were no differences (P>.05) in percentage of carcass weight accounted for by the fore vs. rear halves of carcasses, suggesting there was no difference in the distribution of weight. Although there were differences in longissimus area, the results were not consistent, except that there was a trend for longissimus area to be increased by the use of estrogenic-androgenic implants (ET and EBA). There were no differences among implant sequences for carcass conformation, fat cover, muscle texture, marbling/ feathering, muscle color, or muscle chemical composition. Of four implant sequences (0-0-0, 0-ET-ET, 0-EP-EP, and 0-EP/2-EBA) tested for differences in Warner-Bratzler shear force tenderness, the latter two sequences averaged higher (P<.05) for shear force than did the negative control. These results suggest that aggressive implant strategies in young, intact Holstein bull calves (raised as veal) have minimal effects on carcass characteristics.     

Pulmonary hypertension in a group of dairy calves

An episode of pulmonary arteritis and sclerosis in twenty 5- to 6-month-old dairy calves was investigated. Sixteen of the calves died acutely, without marked premonitory signs of disease. Four calves evaluated clinically had lethargy, pallor, weakness, tachycardia, tachypnea, and jugular venous distention. Cardiac catheterization performed in 3 of the calves revealed pulmonary hypertension; 1 of these calves survived. Necropsy findings in 19 calves included pale lungs and excess free fluid in the pleural and abdominal cavities. In addition, 13 of 19 calves had a dilated and thin-walled right ventricle; 4 of the calves had right-sided cardiac hypertrophy, and 2 had dilatation of the pulmonary artery. Microscopically, pulmonary arteritis and sclerosis of the small to medium-sized arteries were evident in all calves submitted for necropsy. A lung biopsy specimen from a surviving calf had similar lesions. Centrilobular hepatic necrosis was found in 17 of 19 calves. Investigation of the disease episode, including feed analysis for toxins and serologic and microbiological studies of clinically affected calves and clinically normal in-contact penmates, failed to reveal any associated risk factor. The pulmonary arterial changes in the calves were similar to lung lesions in rats fed monocrotaline.