Ultrasonography to investigate the effect of supplementing whole milk with complex carbohydrates and specific amino acids on curd retention in the abomasum of dairy calves

AIM: To determine whether the retention time of curd in the abomasum of calves was influenced by supplementing milk with a plant-derived carbohydrate and amino acid supplement, evaluated non-invasively using ultrasonography.

METHODS: Female dairy calves aged between 2–6 days of age were sourced from a commercial farm in March 2013. All calves were fed whole milk until weaning (4?L per day); 21 calves were supplemented with a probiotic until 18 days of age, and thereafter with a plant-derived complex carbohydrate and amino acid supplement until weaning, and 22 calves were just fed whole milk. Treatment groups were balanced for age, weight and breed. At 9–14, 24–29 and 52–57 days of age, the abomasum of each calf was examined using ultrasonography immediately before and after feeding, 1 and 2 hours after feeding, and then at 30 minute intervals until curd was no longer visible in the abomasum. Abomasal volume and curd size were recorded to assess retention time of curd in the abomasum.

RESULTS: At 9–14 days of age, mean retention time of curd in the abomasum was similar (4.6 hours) in both groups. At 24–29 days of age, when the supplemented calves had been receiving the supplement for approximately 10 days, mean curd retention time was longer by 1.4 (SE 0.28) hours in supplemented compared with unsupplemented calves (p<0.001). At 52–57 days of age, mean retention time was longer by 0.7 (SE 0.34) hours compared to unsupplemented calves (p=0.05).

CONCLUSION: Using ultrasonography, changes in abomasal content could be followed non-invasively over time and it was demonstrated that the plant-derived complex carbohydrate supplement increased the curd retention time in the abomasum. We speculate that the increased retention time enables an increased availability of nutrients following a more complete digestion of milk, thereby improving animal performance.     

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.     

Mortalities in bobby calves associated with long distance transport

OBJECTIVE: To investigate how distance of transportation and time of year affects mortality of bobby calves. METHOD: The overall mortality of bobby calves transported by road to an abattoir in Northern Victoria was investigated by the analysis of mortality data from 1998 to 2000 from the abattoir records. RESULTS: Mortality of bobby calves increased exponentially with distance of transportation to the abattoir. The association between distance travelled and mortality was greatest in August. The increased mortality associated with greater distance travelled occurred during transportation rather than after arrival at the abattoir. The highest mortality of bobby calves was seen in October, followed by September, and the lowest was observed in August. CONCLUSION: Limits on the distance of transportation of bobby calves should be incorporated into future codes of practice to reduce the mortality of bobby calves.     

Ultrasonographic imaging of abomasal curd in preruminant calves

The aim of this study was to determine whether ultrasonography could be used to evaluate curd formation in the abomasum of preruminant calves. Holstein-Friesian calves were fed one of three milk replacers: clotting (five calves), non-clotting (four calves) and pH-dependent clotting (clots form at pH 5.5, but not at pH 6.5; six calves). Ultrasonography was performed until 6h after feeding the milk replacers. In calves fed the clotting milk replacer, a large clot of curd was visualised by ultrasonography as a clearly outlined echogenic image and whey as an anechoic image. In calves fed the non-clotting milk replacer, abomasal contents were visualised as a uniform, entirely echogenic image, indicating the absence of curd formation. In calves fed milk replacer with pH-dependent clotting properties, several small curds and whey were visualised by ultrasonography. It was concluded ultrasonography can be used to visualise abomasal curd and to distinguish the presence and absence of curds in the abomasum of calves.     

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.     

Effect of enhancing curd formation during the first colostrum feed on absorption of gamma glutamyl transferase by newborn calves

OBJECTIVE: To examine the effects of curd formation within the abomasum, on the absorption of gamma glutamyl transferase (GGT) from colostrum in newborn calves. DESIGN: An in vivo physiological study with controls, and in vitro examination of calf abomasal fluid. PROCEDURES: Newborn calves were taken from cows without allowing them to suckle. They were fed either 1.5 kg colostrum or 1.5 kg colostrum plus rennet, with intervals between calving and colostrum feeding ranging from 0.4 to 12.7 h. Absorption of proteins from the whey component of colostrum was assessed from the rise in activity of serum GGT. In in vitro studies, colostrum was incubated with bovine amniotic fluid, newborn calf abomasal fluid or newborn calf forestomach contents, with or without rennet, to test the curd inhibiting effects of components in the abomasal fluid of newborn calves. RESULTS: In vivo: addition of rennet to the colostrum feed reduced the proportion of calves with serum GGT activity below 500 U/L by 60%. In vitro: 43% of newborn calves lacked curd forming activity in their abomasal fluid, and that deficiency was corrected by adding rennet to the incubation medium. CONCLUSIONS: Some calves are born with low amounts of curd forming enzyme activity in the abomasum. This may compromise their ability to absorb large whey proteins from the first feed of colostrum. Adding rennet to the first colostrum feed may improve passive immunity in those calves.     

Bayesian estimation of true between-herd and within-herd prevalence of Salmonella in Danish veal calves

Specialised veal producers that purchase and raise calves from several dairy herds are potentially at high risk of delivering Salmonella-infected animals to slaughter. However, the true prevalence of Salmonella infected veal producing herds and the prevalence of infected calves delivered to slaughter from infected herds are unknown in Denmark. Due to uncertainties about test sensitivity and specificity, these prevalences are not straightforward to assess. The objective of this study was to estimate the within-herd- and between-herd prevalence of Salmonella in veal calves delivered for slaughter to abattoirs in Denmark. Furthermore, it was investigated to which extent the estimates differed between a setup using both serological tests and faecal culture, compared to just serological tests, and whether the applied sampling scheme in the national surveillance programme in Denmark was sufficient to establish high posterior estimates of freedom from infection in individual herds. We used Bayesian analysis to avoid bias as a result of fixed test validity estimates. Serological test results from 753 animals and faecal culture from 1233 animals from 68 randomly selected Danish veal producing herds that delivered more than 100 calves to slaughter per year were used to estimate the prevalences and estimates of freedom from Salmonella. Serological test results of 7726 animals from 185 herds were used to compare the difference in prevalence estimates between serology alone vs. faecal culture combined with serology. We estimated that 34-57% of specialised veal producing herds were infected with Salmonella. Within the infected herds, 21-49% of the animals were infected. Few herds obtained high posterior estimates for the probability of freedom from infection given the collected data, with only six of 68 herds obtaining posterior probability of being infected less than 10%. Furthermore, this study indicated that serology is sufficiently sensitive and specific to be used for estimating the prevalence of Salmonella-infected specialised veal producing herds.     

No abomasal curd formation in pre-ruminant calves after ingestion of a clotting milk replacer

The aim of this study was to ultrasonographically evaluate curd formation in 29 pre-ruminant calves that were fed a clotting milk replacer. Abomasal curd was absent in 8/29 calves at 2 h after feeding. In these eight calves, abomasal contents were observed as an anechoic image with small echogenic spots (five calves), or as an echogenic image with an unclear outline (three calves), but there was no echogenic image with a clear outline corresponding to curd that was visualised in the other 21 calves. The curd was not observed until 7 h after feeding in the eight calves. Our analysis also indicated that the absence of curd formation in the pre-ruminant calves did not have a significant impact on the appearance, appetite and vigour of pre-ruminant calves or on their blood parameters, including serum triglyceride, blood urea nitrogen and glucose concentrations. The study provided the first evidence that the abomasum of some calves does not form curd despite ingestion of a clotting milk replacer.     

A survey of abomasal ulceration in veal calves

Abomasal ulceration was found in 264 of 304 commercially reared veal calves at slaughter. The incidence and severity of lesions were greatest in loose housed calves with access to straw and fed milk substitute ad libitum. The majority of lesions were located in the distal pylorus. There was no evidence that the abomasal erosions and ulcers found in the majority of veal calves affected their growth rate or were deleterious to their welfare. It is suggested that pyloric ulceration may be related to the diet of veal calves.     

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

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 less than 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.     

Behaviour of early-weaned calves in indoor individual cubicles and group pens

Extract

Units have been designed to house calves for veal production, but only recently has a large intensive unit been designed to rear surplus dairy-bred calves for beef production in New Zealand. This was built by the Rangitaiki Plains Dairy Company, Edgecumbe, early in 1973 and consisted of two types of housing: a fully enclosed and insulated calf house with 500 individual cubicles in which to rear the animals till weaning at 5 weeks of age, and a “loafing barn” with slatted walls and sawdust floor to house calves for a further 5 weeks before sale as beef weaners.     

The effect of experimental inhibition of gastric acid secretion on curd formation in abomasum and weight gain of calves

Eight Holstein bull calves were divided into two groups; a non-treated control group and a famotidine treated group. Fresh milk was fed twice a day. The experiment was conducted between 7 and 14 days of age. During the experimental period the control group was injected with physiological saline, and the famotidine group was injected with famotidine, a histamine-H2-receptor blocker, into the jugular vein 30 minutes prior to each feeding. The control group showed maximum curd formation 2 h after feeding at both 7 and 14 days of age. Curd scores of 7-day-old and 14-day-old calves were significantly lower in the famotidine than in the control group at 2 and 4 h after feeding. Most fecal samples from the famotidine group exhibited an acidic smell. The famotidine group showed significantly lower values for both average weight gain and the rate of weight gain from 7 to 14 days of age. The inhibition of gastric acid secretion decreased curd formation in the abomasum as well as daily weight gain compared to non-treated control calves. This suggested that curd formation in the abomasum is important for the weight gain of newborn calves.     

The effect of frequent milk feeding on abomasal curd formation of Holstein calves

In order to understand the effects of the automatic milk replacer feeding system on calf health, we examined the effect of frequent milk feeding on curd formation in the abomasum using ultrasonographic imaging. Eight male Holstein calves were divided into a milk-replacer group and a fresh milk group. Calves were fed twice a day to 12 days after birth (Period A). From 13 days, calves were fed six times a day (Period B). The abomasal fluid was taken by paracentesis. In both periods A and B, the fresh milk group formed bigger curds faster than the milk replacer group. The curd score of the milk replacer group in period B at 2 h was significant lower than those of both groups in period A. The pH in the abomasum was lower in period B than in period A. We could not identify the location of the abomasum in the milk replacer group during period B at almost time points. Our experiment suggests the possibility that frequent feeding of milk replacer causes incomplete hydrolysis of κ-casein as well as curd formation, thus reducing the digestibility compared to the feeding of the milk replacer twice per day or frequent feeding of fresh milk.     

Wastage due to diseases and defects in very young calves slaughtered in New Zealand

Analysis of disease and defect data from a national meat inspection database for very young calves slaughtered in New Zealand up to 1987 revealed low prevalences of diseases and defects but relatively high condemnation rates within particular disease and defect categories. Calves slaughtered between 1987 and 1992 showed a decrease in the total condemnation rate of carcasses from 2.20% to 1.17%. The greatest reductions in condemnation rates were seen in the categories of wounds and bruises and “other” reasons; navel ill (omphalophlebitis) was initially included in the latter category and condemnations due to this condition persisted as the most frequent cause of wastage. The decrease in condemnation rates occurred subsequent to implementation of a national farm-gate quality assurance programme and a scientific investigation of traditional meat inspection carcass condemnation criteria. The former led to an increase in the quality of calves submitted for slaughter and the latter to changes in specifications for meat inspection judgments for several localised and resolved diseases and defects. Alterations to the disease and defect recording categories of the database have resulted in more appropriate national statistics and such a database can be used to identify inconsistencies in the application of meat insDection iudgments between slaughterhouses.     

Wastage due to diseases and defects in very young calves slaughtered in New Zealand

Analysis of disease and defect data from a national meat inspection database for very young calves slaughtered in New Zealand up to 1987 revealed low prevalences of diseases and defects but relatively high condemnation rates within particular disease and defect categories. Calves slaughtered between 1987 and 1992 showed a decrease in the total condemnation rate of carcasses from 2.20% to 1.17%. The greatest reductions in condemnation rates were seen in the categories of wounds and bruises and "other" reasons; navel ill (omphalophlebitis) was initially included in the latter category and condemnations due to this condition persisted as the most frequent cause of wastage. The decrease in condemnation rates occurred subsequent to implementation of a national farm-gate quality assurance programme and a scientific investigation of traditional meat inspection carcass condemnation criteria. The former led to an increase in the quality of calves submitted for slaughter and the latter to changes in specifications for meat inspection judgments for several localised and resolved diseases and defects. Alterations to the disease and defect recording categories of the database have resulted in more appropriate national statistics and such a database can be used to identify inconsistencies in the application of meat inspection judgments between slaughterhouses.     

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.     

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.     

Economic losses from an episode of zinc toxicosis on a California veal calf operation using a zinc sulfate-supplemented milk replacer

An episode of zinc toxicosis in 95 veal calves caused $29,602 in losses to the producer ($315/affected calf), most of them direct, out-of-pocket losses. Increased calf mortality and increased veterinary service costs accounted for a majority (70%) of the losses. Reduction of losses may have been accomplished by removing the source and increasing the roughage content in the diet, or by shipping the animals for immediate slaughter. Given the magnitude of the financial loss, especially those associated with calf mortality, it was concluded that producers should refrain from using large amounts of mineral supplements unless a deficiency has been diagnosed.     

Lactic acid as a decontaminant in slaughter and processing procedures

An attempt was made to interrelate the data obtained in experiments conducted by our Department along beef, veal and pig slaughter lines, using lactic acid (LA) for the decontamination of carcasses, cold and hot boned primal cuts, slaughter byproducts, and butcher's knives. First and foremost it was observed, that provided Good Manufacturing Practices are strictly followed, the microbial load of carcass surfaces will be substantially reduced. LA-decontamination may result in an additional reduction. Since in the early post-mortem period bacteria are not yet attached to the meat surface, LA-decontamination should preferably be applied to the hot carcass. It was demonstrated that, dependent on mode and duration of application, LA sprays not exceeding 1% v/v (beef), 1.25% v/v (veal) and 1.5% v/v (pork) resulted in acceptable carcass colour scores. Blood spots, which are particularly prone to discolouration by lactic acid application, should be removed at an early post-mortem stage e.g. by strong showering. The difference in surface pH between LA-treated and control carcasses disappeared within 72 hours post-mortem. Veal longissimus chops treated with LA solutions up to 2% v/v were not identified by a consumer taste panel as significantly different from controls. The 'immediate' bactericidal effect of LA-decontamination for beef, veal and pig carcasses, as well as for pig liver and veal brain, amounted to approximately 1.5 log cycles for the aerobic colony counts, strongly dependent on substrate and conditions of decontamination. In addition, a 'delayed' bacteriostatic effect was observed during storage, which is probably the result of a prolonged lag phase of acid-injured micro-organisms surviving lactic acid decontamination.(ABSTRACT TRUNCATED AT 250 WORDS)     

Epizootiologic Studies of Shipping Fever of Cattle: I. The Microbial Agents Isolated

Nineteen strains of Pasteurella spp., but no viruses cytopathogenic for bovine embryonic kidney cells were isolated from pneumonic lesions present in “normal” veal calves at slaughter.

In studies on two herds of native cattle and six lots of western feeder calves, Pasteurella spp. were isolated from nasal swabs from healthy cattle and those with shipping fever. Viruses of the psittacosis-lymphogranuloma group were isolated from nasal swabs from animals in five groups. Viruses provisionally identified as bovine enteroviruses were isolated from nasal swabs of calves in two lots.

There was serologic evidence of a temporal association of myxovirus para-influenza 3 (PI3) with shipping fever in three lots of calves. From two of these three lots, strains of PI3 were isolated from ten animals, four of which had clinical shipping fever at the time of virus isolation.