Incidences and effects of diseases on the performance of Swedish dairy herds stratified by production

Incidences of diseases and their effects on reproductive performance and risk of culling in herds stratified by production and estrus detection efficiency were studied. Data were from the Swedish milk and disease recording systems and consisted of records for 33,748 first parity Swedish Friesian cows. A standardized mixed threshold model was used for statistical analyses of categorical outcome variables, and an ordinary linear mixed model was used for continuous outcome variables. An increase in production was associated with increased frequencies of treatments of most diseases, shorter intervals from calving to first artificial insemination, fewer days open, and lower culling rates. Cows treated for metritis, silent estrus, and cystic ovaries had an increased number of days to first artificial insemination and more days open. However, the negative consequences of these diseases on reproductive performance decreased as herd production increased. The risk of culling was higher for cows treated for dystocia, cystic ovaries, and mastitis, but the increase in the risk of culling was lower for higher producing herds. Similar trends were observed when herds were stratified by estrus detection efficiency. The results support the hypothesis that herd management, as characterized by milk production or estrus detection efficiency, is important in the incidences and consequences of diseases. Herd management, measured directly or indirectly, should be considered when the health status or cost of disease for a given herd is evaluated.     

Effect of diseases on the culling of Holstein dairy cows in New York State

The effect of seven diseases on culling was measured in 7523 Holstein cows in New York State. The cows were from 14 herds and had calved between January 1, 1994 and December 31, 1994; all cows were followed until September 30, 1995. Survival analysis was performed using the Cox proportional hazards model to incorporate time-dependent covariates for diseases. Different intervals representing stages of lactation were considered for effects of the diseases. Five models were fitted to test how milk yield and conception status modified the effect of diseases on culling. Covariates in the models included parity, calving season, and time-dependent covariates measuring diseases, milk yield of the current lactation, and conception status. Data were stratified by herd. The seven diseases and lactational risks under consideration were milk fever (0.9%), retained placenta (9.5%), displaced abomasum (5.3%), ketosis (5.0%), metritis (4.2%), ovarian cysts (10.6%), and mastitis (14.5%). Older cows were at a much higher risk of being culled. Calving season had no effect on culling. Higher milk yield was protective against culling. Once a cow had conceived again, her risk of culling dropped sharply. In all models, mastitis was an important risk factor throughout lactation. Milk fever, retained placenta, displaced abomasum, ketosis, and ovarian cysts also significantly affected culling at different stages of lactation. Metritis had no effect on culling. The magnitude of the effects of the diseases decreased, but remained important, when milk yield and conception status were included as covariates. These results indicated that diseases have an important impact on the actual decision to cull and the timing of culling. Parity, milk yield, and conception status are also important factors in culling decisions.     

Prevalence of Coxiella burnetii infection in dairy cattle with reproductive disorders

The prevalence of Coxiella burnetii infection in 207 cattle with reproductive disorders was studied by using an indirect immunofluorescence (IF) test, nested polymerase chain reaction (PCR) and isolation. IF antibodies to phase I and phase II antigens of C. burnetii were found in 122 (58.9%) and 125 (60.4%) of the sera, respectively, and PCR-positives were found in 8 (3.9%) of the sera and in 51 (24.6%) of the milk samples. In addition, C. burnetii was isolated from 51 (24.6%) of the milk samples by inoculating laboratory mice. The results indicate that the IF test plus PCR are useful in the diagnosis of bovine coxiellosis. It is difficult to deny that dairy cattle with reproductive disorders would be one of the important reservoirs of C. burnetii responsible for infection in both animal and human populations in Japan.     

Genetic analysis of clinical lameness in dairy cattle

Scores for clinical lameness from two separate studies were combined, and genetic parameters were estimated based on linear and threshold models. Cows were from 24 herds in Minnesota, Wisconsin, and Virginia. To evaluate clinical lameness, cows were observed walking and were assigned a score between 0 and 4 (where 0 = no observable problems to 4 = inability to walk). Data included 1624 records on 1342 cows. The models included fixed effects of herd visit, parity, and stage of lactation. Random effects were additive genetics, permanent environment to account for repeated records, and residual. Estimates of heritability were 0.10 and 0.22 from the linear and threshold models, respectively. The correlation between ETA from linear and threshold models based on all animals was 0.974. Deregressed ETA of sires and REML were used to estimate genetic correlations between clinical lameness and conformation traits. Among the type traits, foot angle, rear legs (rear view), and rump width had strongest associations with clinical lameness; absolute values for genetic correlations between these traits and clinical lameness were approximately 0.65. Low foot angle, hocking in, and wide rumps were associated with increased clinical lameness. Correlations with strength and body depth ranged from 0.20 to 0.43, indicating that heavier cows were more prone to clinical lameness.     

Effect of the use of bovine somatotropin on culling practices in thirty-two dairy herds in Indiana, Michigan, and Ohio

Data from 5468 Holstein dairy cows in 32 herds were used to determine the effect of the use of bovine somatotropin (bST) on culling practices over a 13-mo period. After an initial herd inventory, monthly information regarding cow entry and exit from the herds was obtained by seven participating veterinarians. Culling was coded by farmers for the following reasons: low production, reproduction, somatic cell count, mastitis, sickness, dairy purposes, lameness, death, and other. In the control herds, cows were not treated with bST during the trial. Adopter herds were defined as herds that utilized supplemental bST for > or = 25% of the cow-days during the trial. Mean herd use of bST in adopter herds was 38.6%. No difference in the number of cows culled per cow-day at risk was detected between control and adopter herds (0.09 and 0.11%, respectively). Amount of in-herd use of bST was unrelated to culling. No significant differences were determined between adopter and control herds in the percentage of cows that were culled for any of the nine possible culling reasons. The results of this study suggest that culling patterns in herds that use bST are unaffected for at least the first year after adoption.     

Evaluation of overall reproductive performance of dairy herds

Production of the bacteriocins enterocin A and enterocin B in Enterococcus faecium CTC492 was dependent on the presence of an extracellular peptide produced by the strain itself. This induction factor (EntF) was purified, and amino acid sequencing combined with DNA sequencing of the corresponding gene identified it as a peptide of 25 amino acids. The gene encodes a prepeptide of 41 amino acids, including a 16-amino-acid leader peptide of the double-glycine type. Environmental factors influenced the level of bacteriocin production in E. faecium CTC492. The optimal pH for bacteriocin production was 6.2. At pH 5.5, growth was slow, and very little bacteriocin was formed. The presence of NaCl or ethanol (EtOH) was also inhibitory to bacteriocin production, and at high concentrations of these solutes, no bacteriocin production was observed. The induction factor induced its own synthesis, and by dilution of the culture 106 times or more, nonproducing cultures were obtained. Bacteriocin production was induced in these cultures by addition of EntF. The response was linear, and low bacteriocin production could be induced by about 10(-17) M EntF. This response was attenuated by low pH or the presence of high concentrations of NaCl or EtOH, and 300 times more EntF was needed to induce detectable bacteriocin production in the presence of 6.5% NaCl. High levels of bacteriocin production in cultures grown at low pH or in the presence of high concentrations of NaCl or EtOH were obtained by addition of sufficient amounts of EntF.     

Abortion and reproductive performance of cattle in northern Nigeria: a questionnaire survey

A survey on abortion and reproductive performance in cattle was carried out in the six northern States of Nigeria in 1972-73. Three hundred and ninetten herds with 8,970 breeding cows were sampled. One hundred and thirteen herds reported abortion (35 per cent); the lowest incidence was in local herds in Kano State and the highest was on government ranches. Twenty-six herds reported recurrent or chronic abortion. The majority of abortions in non-government herds was not reported to local veterinary authorities (75-8-100 per cent). Average age at first conception in government herds was 2-5 years and 3-5 years in local herds. The percentage of calf crop was highest in the government herds (67 per cent) compared with local Fulani herds (34-2-54-5 per cent) and the pregnancy rate was almost double in the government herds. The percentage of Fulani herds reporting repeat breeding varied from 16-6 to 58-8. Although the survey gave no information as to the causes of abortion or the financial loss, it indicated that bovine abortion was more widespread in the northern states of Nigeria, than previously thought.     

Short- and long-term production losses and repeatability of clinical mastitis in dairy cattle

Between 1985 and 1990, a study of 5313 lactations of 2477 Black and White cows was carried out. A stepwise least squares method was used to obtain unbiased estimates of milk, fat, and protein losses that were due to clinical mastitis and the carry-over effect from the previous lactation. Logistic regression was used to estimate the probability that a cow would have clinical mastitis in the next month. The effect of clinical mastitis on production within one lactation was estimated at 527 kg of milk (8.1%), 22.7 kg of fat (8.0%), and 13.7 kg of protein (6.2%) for > or = 3 cases of clinical quarters in the second lactation. One or 2 cases of clinical quarters in a lactation did not significantly affect the production in the next lactation. The negative carry-over effect of > or = 3 cases of clinical quarters was estimated at 381 kg of milk (5.9%), 23.7 kg of fat (8.4%), and 10.1 kg of protein (4.6%) up to and including mo 8 of the second lactation. The fat content in milk produced after the onset of mastitis decreased, and the protein content increased. The risk of clinical mastitis infection in the following month was influenced by month of lactation (a higher risk early in lactation), lactation number (risk increased with lactation number), production level (higher risk for high producing cows), number of clinical quarters in the previous lactation, number of clinical quarters in the previous months of the current lactation, and occurrence of clinical mastitis in the current month.     

The effects of inbreeding on the lifetime performance of dairy cattle

The effects of inbreeding on the lifetime performance of dairy cattle were examined using data for production, somatic cell score, and linear type for all Holstein cows that were scored between 1983 and 1993. The results of fixed and mixed animal models differed. Relative net income adjusted for opportunity cost for the 2,610,123 cows with an 84-mo opportunity for herdlife was depressed by $14.79 for fluid market pricing and by $12.40 for manufacturing pricing per 1% increase in inbreeding. Mixed model estimates of depression per 1% of increase in inbreeding were +0.55 d for age at first calving, -6 d for days of productive life, and -4.8 for days in milk. Inbreeding decreased the mature equivalent production of milk, fat, and protein during first lactation by 27, 0.9, and 0.8 kg and the lifetime production of milk, fat, and protein by 177, 6.0, and 5.5 kg, respectively, per 1% increase in inbreeding. Inbreeding had little effect on conformation traits. The effects of inbreeding were cumulative, and effects on lifetime profit functions were relatively larger than the effects on lactation traits. Registered cows had higher levels of inbreeding and larger standard deviations than did grade cows. Inbreeding in registered cows depressed relative net income adjusted for opportunity cost for fluid and manufacturing prices by $24.43 and $21.78, respectively; income was depressed $9.43 and $9.02, respectively, for grade cows. The difference between registered and grade cattle is likely due to the incomplete pedigree information in grade animals. Inbreeding among cows in this study was not high on average, but economic losses represented a significant cost to the producer.     

The seasonal variation of thermophilic campylobacters in beef cattle, dairy cattle and calves

The epidemiology of clinical cases of campylobacter in temperate climates shows a striking seasonality. In the search for a seasonal environmental reservoir changes in the carriage rate and population size of campylobacters in bovine hosts with time have been measured. Most probable number (MPN) methodology was used to enumerate thermophilic campylobacters in samples taken from the small intestines of beef cattle at slaughter and the fresh faeces of four dairy herds and new-born calves. Statistical analyses revealed significant evidence for seasonal periodicity in the data from dairy herds (P = 0.044). Not only was there a departure from constancy within a 12-month interval but these data revealed a true seasonality, that is, the same periodicity in numbers from one year to the next. Each herd had two peaks per year, in approximately spring and autumn. Peaks coincided in herds on neighbouring farms but those on farms in the north preceded those on farms in the south by 2 and 1 months, respectively (P = 0.0057). Intestinal carriage by beef cattle at slaughter was 89.4% (n = 360) with an average MPN campylobacters per gram fresh weight (MPN gfw-1) of 6.1 x 10(2). Average MPN gfw-1 in faeces from the dairy herds and calves were 69.9 (S.D. 3) and 3.3 x 10(4) (S.D. 1.7 x 10(2)). There was no evidence of seasonal periodicity in the size of the campylobacter population in beef cattle at slaughter. Calves were campylobacter free at birth but became colonized with a few days.     

Associations between self-assessed masticatory ability and some general health factors in a Swedish population

BACKGROUND: A phase III, randomized, double-blind, multi-institutional trial was performed evaluating active specific immunotherapy using vaccinia melanoma oncolysate (VMO) in the surgical adjuvant setting in patients with stage II melanoma (UICC staging). The first interim analysis showed no significant difference in disease-free and overall survival. The data were further analyzed to identify subsets of patients with improved outcome when treated with VMO. METHODS: Patients received either VMO or placebo of live vaccinia vaccine virus (V), once a week for 13 weeks and then once every 2 weeks for an additional 39 weeks or until recurrence. Having stratified patients according to sex, age, number of positive nodes, tumor thickness, and clinical stage, data were analyzed for disease-free survival and overall survival. RESULTS: Male patients showed a 17% difference in overall survival at 4 years when treated with VMO (p = 0.19). A subset of male patients < 57 years of age with one to five positive nodes showed a 30% difference at 4 years with VMO (p = 0.06). Patients with clinical stage I but pathological stage II disease (both male and female), who had undergone prophylactic node dissection, showed a 23% difference in survival at 3 years with VMO (p = 0.11). CONCLUSIONS: This subset analysis shows encouraging survival benefit in certain subsets of patients and an increasing trend in overall survival. Further follow-up of this phase III trial from a second interim analysis will be forthcoming.     

Calculation and use of inbreeding coefficients for genetic evaluation of United States dairy cattle

Inbreeding coefficients are calculated routinely for all animals included in national genetic evaluations for yield traits. The base population for inbreeding is defined as animals born during 1960. Animals with unknown parents are assumed to have inbreeding coefficients that are equal to the mean of coefficients for animals with known parents born during the same year. Mean inbreeding coefficients reached .03 to .04 for recent years, and coefficients for some animals exceeded .50. The annual increase in level of inbreeding was highest for Milking Shorthorns, but the rate of change of that increase was greatest for Holsteins. Accounting for inbreeding in calculation of the inverse of the relationship matrix had only a small effect on evaluations. For Jersey, the maximum change in breeding value was 73 kg of milk for cows and 40 kg of milk for bulls with > or = 10 daughters. Estimates of inbreeding depression were similar across breeds for production traits and were -29.6 kg of milk, -1.08 kg of fat, and -.97 kg of protein per 1% of inbreeding for Holsteins. In January 1994, the USDA began considering the percentage of inbreeding when calculating inverses of relationship matrices, the largest matrix representing over 20 million Holsteins; this inbreeding percentage was released to the dairy industry for bulls.     

Incidence and prevalence of lameness in dairy cattle

A survey was made of 37 dairy farms in Wirral, mid-Cheshire, mid-Somerset and Dyfed, Wales, to assess the incidence and prevalence of lameness in the cows between May 1989 and September 1991. The incidence was obtained from records made whenever a cow was examined for lameness or received preventive foot-trimming. The mean annual incidence was 54.6 new cases per 100 cows with a range from 10.7 to 170.1 and the mean values during summer and winter were 22.9 and 31.7, respectively. The prevalence of lameness was measured by regular visits at which locomotion was scored on a scale of 1 to 5, and the prevalence of lameness was calculated for each visit as the proportion of cows with scores of 3 or more. The mean annual prevalence over the whole period was 20.6 per cent with a range from 2.0 to 53.9 per cent for the 37 farms. The mean prevalences during summer and winter were 18.6 and 25.0 per cent, respectively. The prevalence measured at a single visit in midsummer or midwinter was significantly correlated with the mean prevalence over the whole corresponding period and may be useful as an assessment of the extent of lameness in a herd and the efficacy of control measures. There was evidence that training farmers to recognise early cases of lameness and request veterinary treatment resulted in a marked reduction in the duration of cases of lameness.     

Use of physiologic variables to predict milk yield after clinical mastitis in dairy cattle

OBJECTIVE: To determine the association between intramammary infections caused by various bacteria and hepatic damage, as measured by serum sorbitol dehydrogenase (SDH) activity, WBC counts, and PCV and the association of clinical variables with milk production after a case of clinical mastitis. DESIGN: Prospective, cohort study. ANIMALS: 82 cows with clinical mastitis. PROCEDURE: Information on milk production, mastitis status, and selected physiologic variables was collected during a 1-year period. Milk samples for bacteriologic evaluation were collected on day 1 of an episode of clinical mastitis. Physical examination was performed and blood samples for laboratory evaluation were collected on days 1, 5, and 9. Primary outcome was mature equivalent 305-day (ME305) milk production. Correlations were assessed using a multiple regression model. RESULTS: Higher WBC counts were associated with higher ME305 values. For cows with coliform mastitis, increases in SDH values were associated with higher ME305 values. For cows with coliform and streptococci/staphylococci mastitis, PCV was associated with ME305 values. Higher PCV values were associated with lower ME305 values for streptococci/ staphylococci and coliform infections. CLINICAL IMPLICATIONS: The association between milk production and WBC count indicated that cows mobilizing WBC were better able to neutralize mammary gland infections, which may result in better milk production. The association between milk production and PCV suggested that maintaining hydration in cows with clinical mastitis may be a critical aspect of treating all cows with mastitis.     

The detection of oestrus in dairy cattle

A survey attempted to determine the extent to which cows are being inseminated when not in oestrus. The method used to check the farmers' diagnoses of oestrus was based on peripheral plasma progesterone concentrations analysed by radioimmunoassay. Of 141 cows examined in this way, a total of 30 (21-28 per cent) showed abnormalities of the progesterone levels. The fertility within this group was very poor with only two of the cows being known to have conceived to the service in question.     

Aetiology and Pathogenesis of abomasal displacement in dairy cattle

A clinical chemical survey is given of the complex of factors which are involved during development of clinically manifest hypotony or atony of the abomasum prior to abomasal displacemnts. The importance of a change in the acid-base balance of the animals is especially stressed as a predisposing factor. The further pathogenesis of abomasal displacement is supposed to follow different ways, according to the feeding and to prevailing periods of indigestion.     

Relationships between the presence of Johne's disease and farm and management factors in dairy cattle in England

The data collected by a postal questionnaire sent to 3772 randomly selected dairy farmers in England and the border regions in Wales were used to estimate the relationships between the presence of clinical Johne's disease and farm and management factors associated with that disease. Two binary outcomes (case reported in 1993, case reported in 1994) and 27 predictor variables were considered. Only two variables were consistently and significantly associated with clinical disease in multivariable analysis. Farms on which Channel Island breeds were predominant were associated with an increased risk of reporting disease (odds ratios (ORs) ranged from 10.9 to 12.9). The presence of farmed deer on the farm also increased the risk of reporting disease (ORs ranged from 15.2 to 209.3). There were other significant but inconsistent associations involving the source of replacements, age of first-offering hay, type of concentrate feed to calves, and calving in individual pens when the cows were at grass. Since Johne's disease is predominantly subclinical, these contributing factors may play important roles in switching subclinical infection to overt disease.     

Associations between family structure, family functioning, and substance use among Hispanic/Latino adolescents.

This study examined the role of family structure and functioning in predicting substance use among Hispanic/Latino adolescents, surveyed in 9th and 10th grade. The sample (N = 1433) was half female, mostly of Mexican descent, and the majority was born in the United States. Living with a single father was associated with less parental monitoring and less family cohesion (γ = ?0.07, ?0.06, respectively). Living with a single mother was associated with less parental monitoring (γ = ?0.10). Living with neither parent was associated with less communication (γ = ?0.08), less parental monitoring (γ = ?0.09), more family conflict (γ = 0.06), and less family cohesion (γ = ?0.06). Less monitoring was associated with substance use at follow-up (β = ?0.17). Low rates of parental monitoring appear to mediate the association between parental family structure and substance use. Results suggest that improving basic parenting skills and offering additional social support and resources to assist parents in monitoring adolescents may help prevent substance use. These interventions may be particularly beneficial for single parents. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Milk production and reproductive performance in dairy cows given bovine respiratory syncytial virus vaccine prior to parturition

OBJECTIVE: To assess the effect of vaccination against bovine respiratory syncytial virus on milk production, reproductive performance, and health in lactating dairy cows. DESIGN: Prospective randomized block design. ANIMALS: 385 Holstein dairy cows and heifers. PROCEDURE: Cows were grouped by lactation number, season of calving, and previous mature equivalent 305-day milk production (where appropriate). Prior to parturition, cows and heifers were randomly assigned to be vaccinated i.m. against infectious bovine rhinotracheitis, bovine viral diarrhea, and parainfluenza 3 viruses by use of a three-way vaccine, or to be vaccinated against those viruses as well as bovine respiratory syncytial virus, using a four-way vaccine. Milk production was measured daily through 305 days of lactation. Reproductive and medical records were reviewed to obtain insemination dates and record medical problems of cows in each vaccine treatment group. RESULTS: Compared with the three-way vaccine, administration of the four-way vaccine was associated with higher milk production (1.39 kg [3.06 lb] more milk/d) in first-parity cows during the first 21 weeks of lactation. Vaccination did not have any effect on milk production after the first 21 weeks of lactation in cows of any parity. Conception rates at first insemination were higher for four-way vaccinated first-parity cows than for three-way vaccinated first-parity cows (54.6 vs 32.7%). Compared with second-parity cows that received the three-way vaccine, first insemination conception rate was improved for second-parity cows vaccinated with the four-way vaccine (28.9 vs 47.8%, respectively). In cows of third or greater parity, first insemination conception rate was not different between the 2 vaccine treatment groups. CLINICAL IMPLICATIONS: Vaccination of heifers against bovine respiratory syncytial virus prior to partrition may increase milk production and first insemination conception rates.