Cull Dairy Cows Research Articles

Escherichia coli O157 in Cull Dairy Cows on Farm and at Slaughter

Cull dairy cattle both on the farm and at slaughter from herds in the states of Idaho, Oregon, and Washington were surveyed for Escherichia coli O157 by culturing fecal swab samples. A total of 205 cull cows from 19 dairy herds were sampled on the farm of origin; 7 (3.4%) tested positive for E. coli O157. A total of 103 cull cows from 15 dairy herds were sampled at slaughter; 4 (3.9%) were positive for E. coli O157. Eighty-nine cull cows were sampled both at the farm and at slaughter; 2 (2.2%) were positive in both locations, 3 (3.3%) only on the farm, and 2 (2.2%) only at the slaughter plant. Seven (7.9%) of the 89 cull cows tracked from farm to slaughter were positive in at least one location. This suggests a higher prevalence of E. coli O157 in cull dairy cattle than previously has been reported to occur in other ages and classes of cattle.

Meat from dairy cows: possible microbiological hazards and risks.

The authors provide an overview of the circumstances associated with culling of dairy cattle in the United States of America (USA) and focus on the possible significant microbiological hazards associated with meat from cull dairy cows. Cull dairy cows are an important source of food in the USA, accounting for at least approximately 17% of ground beef. The potential microbiological hazards for foodborne illness from cull dairy cows discussed here include Salmonella (with special attention to S. Typhimurium DT104), Escherichia coli O157:H7, Campylobacter jejuni, Listeria monocytogenes, Clostridium perfringens and Staphylococcus aureus. Possible sources and means of contamination are pointed out, as are the potential foodborne risks from Bacillus cereus and Aeromonas spp. In conclusion, widespread microbiological studies are needed to determine the prevalence and risk of foodborne pathogens in cull dairy cattle.

A lameness scoring system that uses posture and gait to predict dairy cattle reproductive performance

Lameness has contributed to reproductive inefficiency and increased the risk of culling in dairy cows. We developed a 5-point lameness scoring system that assessed gait and placed a novel emphasis on back posture. Our objective was to determine if this system predicted future reproductive performance and the risk of culling. The study was conducted at a commercial dairy farm with a history of declining reproductive efficiency and an increasing prevalence of lameness. A total of 66 primipara and pluripara calved, received an initial lameness score, and completed their 60-d voluntary waiting period. The overall prevalence of lameness (mean lameness score >2) was 65.2%. Scoring continued at 4-wk intervals and ceased with conception or culling. The percentage of cows confirmed pregnant and culled was 77.3 and 22.7, respectively. For each reproductive endpoint, a 2 × 2 table was constructed with lameness score >2 as the positive risk factor and either performance greater than the endpoint mean or being culled as the positive disease or condition. Positive and negative predictive values, relative risk, Chisquare statistic and regression analysis were used to evaluate the data. The positive predictive values for days to first service, days open, breeding herd days, services per pregnancy and being culled were 58, 68, 65, 39 and 35%, respectively. Similarly, the negative predictive values were 79, 96, 100, 96 and 100%, respectively. Except for one reproductive endpoint, the total number of services, all linear regressions were significant at P < 0.01. Having a lameness score >2 predicted that a cow would have extended intervals from calving to first service and to conception, spend or be assigned to (explained herein) more total days in the breeding herd, require more services per pregnancy and be 8.4 times more likely to be culled. We believe that this lameness scoring system effectively identifies lame cows. Observation of the arched-back posture in a standing cow (≥LS 3) should trigger corrective interventions.

EFFECTS OF DATA PREPROCESSING ON THE PERFORMANCE OF ARTIFICIAL NEURAL NETWORKS FOR DAIRY YIELD PREDICTION AND COW CULLING CLASSIFICATION

The effect of data preprocessing on the learning ability of artificial neural networks was investigated with regardto the impact of distributing the input vectors uniformly with respect to the output categories in the training data set. Theanalyses were performed for neural networks dedicated to (1) dairy cow culling classification and (2) milk yield prediction.The two types of neural network used for culling classification were backpropagation and learning vector quantization. Foryield prediction, backpropagation was used. The study was repeated with several architectures for both types of network.Preprocessing of data did not have a large impact on the general performance of the networks, but did affect the results foreach output category. The effects were more pronounced in the categories containing less frequent events, for which theresults always improved. For the categories with larger number of records, balancing the data degraded the results. Therespective improvements and degradation of the results occurred for both prediction and classification, with the two types ofneural networks, and with all architectures tested. However, the magnitude of the effects varied with the type of neuralnetwork and with the architecture. The results of this study indicate that, in general, the distribution of outputs influences thelearning process of neural networks for both types of application. The results also suggest that the types of outputdistribution required for the training of neural nets may depend on the specifics of each problem.

The effect of the β-adrenergic agonist cimaterol on performance and carcass and meat quality in culled dairy cows

AbstractForty-eight culled dairy cows were assigned to one of two treatment groups to investigate the effect of a β-adrenergic agonist in mature cattle. They were finished during a 63-day period on a concentrate diet, containing 0 or 4 mg/kg cimaterol. No food was given in the 20 h prior to slaughter.Cimaterol had no effect on food intake, but significantly improved food conversion efficiency and increased live-weight gain, carcass weight and dressing proportion (P &lt; 0·05). Cimaterol induced muscle hypertrophy as evidenced by an improved EUROP carcass classification and a higher longissimus thoracis (LT) cross-sectional area (P &lt; 0·001). EUROP fat score and fat content in the carcass and the LT were lowered (P &lt; 0·05). Cimaterol resulted in brighter meat (higher L-value: 37·0v.35·6; P&lt;0·05) with a higher shear force value (64·0v.46·4 Newton; P&lt;0·01) compared with control animals. It seems likely that mature cattle receiving cimaterol respond similarly to younger growing animals.

Associations between health disorders during two consecutive lactations and culling in dairy cows

Data from an observational study, carried out from 1986 to 1990, were used to quantify the effects of 15 main health disorders during two consecutive lactations on the risk of culling in the latter one. The study population consisted of 47 commercial Holstein herds from western France, comprising 4123 cows. Logistic regression was used to assess the relationship between health disorders and culling within and after 45 days post-partum. Adjustments were made for year, month of calving, parity, breeding value for milk, best of the two first milk production records and reproductive performance. Effects of interactions were investigated. Herd effect was accounted for using random effect models. Few diseases from the previous lactation were related to culling in the current lactation. Non-traumatic udder disorders, teat injuries, mastitis, high milk somatic cell count, abortion and metritis from the previous and current lactations were dominant with respect to culling within and after 45 days post-partum. The risk of being culled within and after 45 days post-partum increased with higher parity and lower breeding value for milk. Lower previous 305-day milk production and poor reproductive performance increased the risk of culling within and after 45 days post-partum respectively.

Prevalence of Fecal Salmonella Shedding by Cull Dairy Cattle Marketed in Washington State

On nine occasions over a 1-year period, cull dairy cattle (n = 1,289) at four saleyards and one abattoir in Washington State were surveyed for salmonellae shedding by bacterial culture of duplicate rectal swabs, 251 single fecal samples and duplicate rectal swabs, and 225 mesenteric lymph node and duplicate rectal swabs. Using parallel selective enrichment and brilliant green media, salmonellae were isolated from six cattle, from rectal swabs only, and consisted of five isolates of Salmonella typhimurium and one of Salmonella dublin. In the two rectal swab- positive cattle for which mesenteric nodes were also sampled, 1-g samples of the nodes were negative. The rate of fecal shedding of cull dairy cattle marketed in Washington State as detected by this methodology is estimated to be 4.6 per 1,000 head (95% confidence interval of 1.9 to 10.6) and is expected to be no higher than 9.2 per 1,000 head if larger fecal samples were used. Based on antibiograms and plasmid profiles, none of the six isolates matched any of the 280 previously characterized isolates of the same serotypes obtained from human salmonellosis cases 2 years previously by the State health department. Four of the five S. typhimurium isolates matched three of 215 S. typhimurium isolates obtained from bovine submissions to the State's animal disease diagnostic laboratory and by a field animal disease investigation unit. The S. dublin isolate matched 17 of the 165 S. dublin isolates in those submissions. In this State, swab sampling of cull dairy cows at the point of first market concentration does not appear to be an efficient method of detecting salmonellae- infected dairy herds.

The economics of culling dairy cows with clinical mastitis.

Culling dairy cows with clinical mastitis reduces the incidence of the disease in dairy herds, but the costs of such action, in terms of reduced milk production and increased replacement costs, are generally thought to outweigh the benefits. To test this hypothesis a stochastic dynamic programming model was developed to establish the economically optimum time of replacement for dairy cows subject to variable levels of clinical mastitis infection, using average United Kingdom production and price parameters. The optimal stage at which to replace a dairy cow was found to be sensitive to changes in mastitis incidence and in critical price parameters within the bounds of commercial experience. This result indicates that an objective culling policy based on clinical mastitis records in addition to milk production potential may be economically viable.

Associations between health disorders and culling of dairy cows: a review

Research into the relationships between diseases of cows and culling in dairy herds is reviewed with emphasis on both results and their factors of variation. Tables provide comparisons between studies depending on their designs and their results. Differences between the study populations are outlined. The studied health disorders are extensively reported and their risks of misclassification are discussed. The other variables considered as possible risk factors for culling are reviewed. Some individual characteristics of cows (age, milk production level, reproductive performances) are usually taken into account in the analyses, whereas the herd effect on the individual risk of culling is poorly documented. The statistical methods for the analysis of health disorders as risk factors for culling are summarized. Certain health disorders (dystocia, mastitis) increase the risk of culling regardless of the production systems considered. However, for other health disorders (milk fever, metritis, cystic ovaries, retained placenta, locomotor disorders), contradictory results are reported. These discrepancies may result from either actual differences in the production systems studied or differences in methodologies used. The interest of further studies investigating especially the herd effect on the individual risk of culling is displayed.

Development and testing of a bovine trichomoniasis vaccine

Eighteen culled dairy cows were randomly allocated into 1 of 5 treatment groups. Six cows were vaccinated twice (2V), 21 days apart, 3 with whole cell (2WC) and 3 with fragmented cell membrane (2FC) containing 1 × 10 9 Trichomonas fetus organisms or protein equivalent in a commercial mineral oil adjuvant vaccine. Six more cows were vaccinated once (1V), 3 with whole cell (1WC) and 3 with fragmented cell vaccine (1FC), using the same vaccine, while 6 cows were used as the unvaccinated controls. All cows were challenged with 1 × 10 5 organisms 4 weeks after the second or the only vaccination. After challenge, cervico-vaginal mucus (CVM) samples were cultured for T . fetus weekly for 9 weeks. Whole cell vaccines were superior to fragmented cell vaccines, and both performed better than no vaccination for apparent elimination of trichomonad infections in dairy cows. In addition, 2V was superior to 1V, which, in turn, was superior to no vaccination. Furthermore, clearance time was reduced most by 2V and whole cell vaccination compared with 1V and fragmented cell vaccination. Clearance time was decreased significantly in all vaccinated cows compared with that in unvaccinated cows.

The effect of postexsanguination infusion of beef on composition, tenderness, and functional properties

Ninety culled dairy cows were used in this study and were paired by weight and conformation similarity. Forty-five cows were arterially infused immediately after bleeding with 10% volume by weight of a solution composed of dextrose (.23%), glycerin (.21%), a phosphate blend (.14%) and maltose (.1%). The remaining cows (45) served as controls. In infused carcasses, some quantity of solution retained was in the following order: supraspinatus, chuck greater than longissimus, loin greater than semitendinosus, round muscles. Accordingly, percentage of protein, ether-extractable fat, and protein fat-free amounts were lowered (P less than .05) and percentage of moisture and moisture protein ratio were raised (P less than .05) in the supraspinatus muscle. Tenderness (P less than .01) and protein extractability (P less than .15) were improved. No difference was observed in water-holding capacity between infused and control carcasses. Percentages of moisture fat-free (r = .85) and protein fat-free (r = -.97) were highly correlated to moisture-protein ratio. Moisture percentage of the fat-free tissue was shown to be a more consistent indicator of added moisture in infused whole carcasses compared with moisture:protein ratio and percentage of protein fat-free. Very low correlations were observed between tenderness, percentage of moisture, percentage of water-holding capacity, and ether-extractable fat. The economics of the infusion process to the beef industry is discussed.

Dairy Practitioner and the American Veterinary Medical Association/ National Milk Producers Federation Quality Assurance Program for Milk and Dairy Beef

The Milk and Dairy Beef Quality Assurance Protocol (MDBQAP)1 began as a collaborative effort on the part of the American Veterinary Medical Association (AVMA) and the National Milk Producers Federation (NMPF) to overcome unfavorable publicity, which was scientifically unsubstantiated, regarding pharmaceutical residues in milk which had been sold in certain areas of the United States. In addition there existed concern over the incidence of pharmaceutical residues occurring in cull dairy cows as reported by the U.S. Department of Agriculture, Food Safety Inspection Service. Since both veterinarians and producers were implicated in these issues, it was loitcal that the two organizations cooperate and respond in a proactive manner.

Genetic Parameters of Conformation Traits, Milk Yield, and Herd Life in Holsteins

Genetic parameters were estimated simultaneously for 5 herd-life traits, 15 conformation (type) traits, and milk yield measured in first lactation for 128,601 Holstein cows. Heritabilities of all traits were higher in registered than in grade cows. Genetic correlations of linear type traits with first lactation yield ranged from ∼.48 for udder depth to .54 for dairy form. Genetic correlations among milk yield and herd-life traits were all positive except for milk-corrected herd life in grade cows. Udder traits had largest absolute genetic correlations with herd-life traits, followed by body traits and feet and leg traits. Some traits associated with body size and foot angle differed between registered and grade cows.Estimates of genetic trends from obtained parameters revealed greatest progress for milk yield from single-trait selection but also the largest changes for some type traits and milk-corrected herd life in an undesirable direction. Relative milk to type ratios of between 2:l and 3:1 yielded 90% of the gain in milk yield with no change or slight improvement in type traits and functional herd life. Selection for type traits associated with herd life appears to be warranted to improve days of functional herd life or to decrease involuntary culling of dairy cows.

Production and Economic Effects of Johne's Disease in Dairy Cows

Johne's disease (paratuberculosis) (JD) is a chronic progressive bacterial enteropathy. Infected animals have generally been exposed to the organism at a very young age. Clinical signs of weight loss and diarrhea are often preceded by a period of months or years during which M. paratuberculosis organisms are shed in feces. The effect of subclinical JD on production and economic parameters has not been well characterized.&#x0D; A study of randomly selected cull dairy cows was conducted at a large plant slaughtering cull cows from throughout the northeastern U.S. Johne's positive cull cows weighed less, produced less milk during their lifetime and less milk during their last lactation than did Johne's negative cull cows.

Johne's disease in cattle

Paratuberculosis (Johne's disease) occurs worldwide and is widespread in the United States. A slaughter survey in cows from northeastern states estimated the prevalence of paratuberculosis in cull dairy cows at 7.3% and a similar survey in Wisconsin revealed a 10.8% prevalence.&#x0D; Economic losses due to paratuberculosis may include decreased milk production, premature culling, and increased susceptibility to other diseases. In Pennsylvania alone, over 500 herds positive for Johne's disease have been identified with economic losses estimated at $5.8 million annually. Of the 10.8 million dairy cows in the U.S., nearly 1 million are thought to be affected, and the total losses due to paratuberculosis are expected to exceed $1.5 billion annually for the dairy industry in the United States.

The benefits of animal identification for food safety.

The Center for Veterinary Medicine supports the effort to have a practical, workable form of mandatory animal identification. An animal identification system will make tracing of the source of animals with drug or chemical residues quicker and more effective. One of the best means of addressing and solving the problem of residues is through mandatory livestock identification. A successful traceback benefits both the producer and the industry. The U.S. Department of Agriculture (USDA) has proposed a mandatory nationwide system to require that all swine in interstate commerce be identified. Under the proposal several means of identification are listed and could be used. Additional methods or devices could be requested in writing to USDA. Persons required to keep records under the system would maintain the documents at their place of business for 2 yr. Records would be available to authorized USDA employees during ordinary business hours. FDA has had difficulty tracing tissue residue violations, particularly those involving sulfamethazine residues in swine. Investigations involving culled dairy cows and veal calves also have been closed due to lack of producer identification. The ability for FDA to determine the source of residues is vitally important in a coordinated government program to eliminate illegal tissue residues.

Risk factors for reason-specific culling of dairy cows

A set of 7763 Holstein lactations from 34 New York herds was used to explore the influences of production and of 13 diseases on culling. Dying was predicted by high milk yield and by downer cow syndrome. The cows most likely to be sold for dairy purposes were those with shorter previous-lactation calving intervals, with lower milk per calving-interval day in the previous lactation, who calved in the summer, or who had clinical mastitis. Lower estimated transmitting ability for milk, lower milk yield per day in the previous calving interval and calving in the summer (but not clinical mastitis) were risk factors for low production. Having > 3 services, aborting and having cystic ovary were associated with culling for poor reproduction. Culling for udder problems was predicted by lower previous-lactation milk per day, higher current milk per day, clinical mastitis and teat problems. Cows with lower estimated transmitting ability, dystocia, or foot or leg problems were at higher risk of culling for feet and legs. Culling for miscellaneous reasons was associated with lower estimated transmitting ability, higher current milk per day and left displaced abomasum.

Descriptive epidemiology of culling in dairy cows from 34 herds in New York State

Data on parity, disease, farmers' stated primary reasons for culling and stage of lactation at diagnosis and at culling were used to describe patterns of culling in Holstein lactations from 34 New York herds. Of 7763 lactations, 18.7% ended in culling [death (95 cows), sales for dairy purposes (104 cows), or slaughter]. The culling rates for specific reasons were: dairy purposes 1.3%, low production 3.8%, reproduction 4.8%, udder problems 4.0%, feet and legs 1.2%, old age 0.3%, accidents 0.3% and miscellaneous reasons 2.9%. Culling increased with parity (at least through Lactation 6) and primarily was due to production, reproduction and udder problems. Culling for these 3 reasons peaked immediately after calving, again between 151 and 240 days post-partum (poor milk production) and at 240 days post-partum (poor reproductive performance). First-lactation cows sold for dairy use tended to be sold in early lactation. Death in older cows usually occurred early in lactation and was due to udder problems or to miscellaneous causes. Compared to lactations without the disease, lactations with a diagnosis of downer cow, clinical mastitis or treat problems were 3.5, 2.0 and 2.7 times more likely to end in culling, respectively. Among cows diagnosed with a disease and culled, many were culled the same day or within 30 days of the diagnosis. Such “immediate” culling upon diagnosis was especially typical of cows with milk fever, downer cow syndrome, left displaced abomasum, teat problems, and foot and leg problems (and for some cases of clinical mastitis), implying that these disorders led to “forced” culling, which was particularly costly to the farmers.

Dairy Cow Culling Decision. 3. Risk of Culling on Predicted Income (An Application of Bayes Criterion)

Comparison of cows on their potential for income production or cash flow over multiple calving intervals has been utilized for culling. The reliability of income projections several years in the future may be questioned when the economic environment is uncertain. The problem would be apparent when cull candidates differ in age since a mature cow would be selected for immediate productivity whereas the immature cow would be selected for her long-term potential. When an uncertain change in the economic environment (e.g., milk price) results in a difference in ranking of two cull candidates, the Bayes criterion of selecting the animal with the highest expected value for income can be utilized. A sensitivity analysis can then determine the dependence of the decision on variation in milk price or other states of nature. The value of perfect information would assess the financial risk associated with the decision. In an example analyzed with a probable 5% decline in milk prices, information that would reduce the variability in predicting animal performance had more effect on the payoff of the culling decision than more accurate predictions of future milk prices.

Dairy Cow Culling Decision. 2. Profitability and Genetic Trend in Herds with Culling on Production Versus Income

A technique has been described for culling cows on a combination of screening the entire herd on short-term income and then culling the cow making the smallest contribution to herd income over probable remaining herd life. The objective of this study was to determine the long-term effects on herd profitability and herd genetic trend of culling on a combination of short-term and long-term cow income instead of culling on age adjusted production. In addition, the effect of timing of the culling decision either prebreeding (to save insemination costs) or postbreeding (when time of next freshening can be predicted) on herd income was evaluated. Culling on projected income increased herd income over 20 yr by 4.3 to 4.8% relative to culling on age adjusted production for complete lactation. Breeding only the highest producing cows and then culling infertile cows at the point of peak income in the lactation increased herd income over 20 yr by 4.3 and 5.7% relative to breeding all cows and then culling the lowest producing cow in the herd when a heifer freshened. Cow culling on income projections decreased the genetic trend to 65.3 to 86.2% of the gain observed with cow selection on age adjusted production. Due to the potential economic benefits from both choosing culls prebreeding and utilizing a profitability criterion for cow culling, income projection techniques that describe the reproductive performance of the open cow need to be developed.