Persistent bovine viral diarrhoea virus infection in US beef herds.

In the summer of 1996, we screened 18,931 calves in 128 beef herds located in five US states for persistent bovine viral diarrhea virus (BVDV) infection. Of these, 76 herds were randomly selected from the client database of collaborating veterinary practices, and 52 herds were suspected by the collaborating veterinarians to have BVDV infection based on history or clinical signs. Serum was obtained from each calf in the cooperating herds prior to 4 months of age and tested for the presence of BVDV by microtiter virus isolation. Information about each of the herds (including management practices, vaccination history, and breeding- and calving-season production measures) were collected by the collaborating veterinarians using standardized questionnaires. A total of 56 BVDV-positive calves in 13 herds were identified on initial screening. Ten (19%) of the BVDV-suspect herds and three (4%) of the randomly selected herds had > or = 1 BVDV-positive calf at initial screening. Multiple BVDV-positive calves were identified in 10 of those 13 herds. Follow-up information was obtained for 54 of the 56 positive calves. Ten out of 54 (18%) died prior to weaning, and 1 (2%) was sold because of unusually poor growth. Thirty-three out of 54 (61%) of the initially positive calves remained BVDV positive at 6 months of age - confirming persistent-infection (PI) status. Dams of 45 of the 56 positive calves were tested, with 3 (7%) identified as positive - indicating most PI calves were products of acute dam infection during gestation. The proportion of cows that were pregnant at the fall 1995 pregnancy examination was 5% lower in herds with PI calves born during the 1996 calving season than in randomly selected herds without PI calves. Most of the calves we identified with persistent BVDV infections survived to weaning, and could provide a constant source of virus to the herd throughout the breeding season and early gestation.

Serum concentrations of insulin-like growth factors and placental lactogen during gestation in cattle. II. Maternal profiles.

This study was designed to examine the effects of fetal growth potential on maternal hormones and lipid metabolism. Sixty beef heifers were inseminated with semen from sires with high (H) or low (L) expected progeny differences for birth weight. Maternal serum was collected at 21-d intervals from Day 85 to Day 274 of gestation. Serum concentrations of insulin-like growth factor (IGF)-I, IGF-II, placental lactogen (PL), and nonesterified fatty acids (NEFA) were determined and correlated to fetal and maternal characteristics. Maternal serum IGF-I declined throughout pregnancy, whereas IGF-II was relatively constant and PL tended to increase. Maternal serum NEFA was low and invariant through Day 211 of gestation when it rose 3.5 times to peak levels at Day 253 and declined at Day 274. PL was positively correlated to NEFA (r = 0.37, P < 0.01), IGF-I was negatively correlated (P < 0.01) to NEFA and PL (r = -0.59, and -0.35, respectively), and IGF-II was negatively correlated to NEFA (r = -0.35, P < 0.01). Dams pregnant with H fetuses had lower (P = 0.02) serum IGF-I and tended to have higher (P = 0.09) serum PL concentrations than dams carrying L fetuses. Additionally, dams pregnant with L fetuses had higher (P < 0.03) serum IGF-II concentrations than dams with H fetuses (175.6 vs. 145.0 ng/ml) during the third trimester. Fetal sex had no effect on any maternal serum parameter. Fetal weight and instantaneous growth rate (IGR) were positively correlated to maternal NEFA and PL and negatively correlated to maternal IGF-I and IGF-II. Independent IGR effects were detected for PL (P < 0.06) and IGF-I (P < 0.0005) concentrations. Maternal hip height was negatively related to serum IGF-I and positively related to serum PL concentrations. Maternal body weight and body condition score were correlated with several serum parameters but were confounded by day of gestation. Correlation analysis of serum concentrations of IGF-I, IGF-II, and PL did not support the hypothesis that PL regulates IGF concentrations.

Serum concentrations of insulin-like growth factors and placental lactogen during gestation in cattle. I. Fetal profiles.

Sixty crossbred beef heifers pregnant with fetuses of either high (H; n = 30) or low (L; n = 30) genetic potential for growth were used to establish fetal serum profiles of insulin-like growth factor (IGF)-I, IGF-II, and placental lactogen (PL), and to examine relationships between serum hormone concentrations and fetal growth parameters. Three H and three L fetuses were collected by caesarean section at 21-d intervals from Day 85 through Day 274 of gestation. Arterial, venous, and mixed umbilical blood samples were collected during surgery. Fetal body weight, crown-rump length, hip height, and heart girth were measured. Serum concentrations of IGF-I and IGF-II increased (P < 0.0001) with advancing gestational age, whereas serum PL declined (P < 0.0001) linearly (P < 0.01) throughout gestation. Serum concentrations were greater in the umbilical vein compared with the umbilical artery for IGF-II (P < 0.0001) and PL (P < 0.05), but not IGF-I. Fetal IGF-I, IGF-II, and PL serum concentrations were not correlated with serum concentrations of the respective maternal hormones. Fetal serum IGF-I concentrations were correlated to fetal body weight (r = 0.66), growth rate (r = 0.72), crown-rump length (r = 0.20), hip height (r = 0.17), and heart girth (r = 0.20). Correlations between fetal serum IGF-II concentrations and the same parameters were 0.60, 0.62, 0.39, 0.34, and 0.37, respectively. Fetal serum PL concentrations were negatively correlated to body weight (r = -0.40) and growth rate (r = -0.40) and not correlated with any fetal linear measure. Fetal genotype (L vs. H) differences were detected for IGF-I (P < 0.05) and PL (P = 0.09) concentrations. Fetal sex effects were not observed for any hormone. Maternal sire breed, hip height, and body condition score did not influence fetal serum hormone concentrations.

Vitamin E supplementation and stress affect tissue alpha-tocopherol content of beef heifers.

The effect of stress on tissue alpha-tocopherol was investigated in 16 crossbred heifers fed a corn/corn silage-based diet. For 28 d, eight heifers (379 +/- 10 kg BW) received a dietary supplement of 1,000 IU of dl-alpha-tocopheryl acetate, whereas the controls (375 +/- 10 kg BW) received no supplemental vitamin E. Tissue samples of plasma, red blood cells, liver, trapezius, and longissimus muscles and subcutaneous fat immediately dorsal to each muscle were taken on d 1 for determination of alpha-tocopherol concentration. On d 2 through 4 each heifer was restricted to 2.61 kg of grass hay and allowed water. On d 5, 6, and 7 no feed or water was given, 100 IU of ACTH and .0024 mg of epinephrine/kg BW were given every 8 h, and biopsies for alpha-tocopherol content were again taken on d 7. The stress reduced (P < .01) mean BW, increased (P < .01) serum cortisol, creatine kinase, and urea. After stress, supplemental vitamin E reduced (P < .13) the increase in creatine kinase relative to that in heifers not supplemented with vitamin E. Stress also increased (P < .04) serum Se in heifers fortified with the vitamin E. Alpha-tocopherol content of plasma, red blood cells, liver, and subcutaneous fat dorsal to the trapezius muscle was increased (P < .01) by supplemental vitamin E. The stress treatment reduced (P < .01) alpha-tocopherol content of plasma in those fed the vitamin E and increased it (P < .05) in the nonsupplemented vitamin E-deficient heifers. Stress also decreased red blood cell (P < .01) and liver (P < .05) alpha-tocopherol content in cattle supplemented with vitamin E. Tissue alpha-tocopherol concentrations were reduced by stress only when a diet adequate in vitamin E was fed. In addition, in most sampled tissues, stress did not affect alpha-tocopherol concentrations.

Injection-site lesions in carcasses of cattle receiving injections at branding and at weaning.

Crossbred steer and heifer calves (n = 84) were given injections at branding and at weaning (using a completely randomized block design); 225 to 376 d later, pairs of two subprimal cuts from each animal were evaluated for incidence and severity of injection-site lesions. The four products compared were 1) a 2-mL clostridial, 2) a 5-mL clostridial, 3) vitamin AD3, and 4) a long-acting oxytetracycline antibiotic (OTC). Branding-age calves (mean 48.3 d of age) received intramuscular injections of two of the four products, in the semimembranosus (inside round) muscles (one in the left muscle and one in the right); at weaning age (mean 199.3 d of age), calves received injections of the remaining two products in the gluteus medius (top sirloin butt) muscles (one in the left and the other in the right). Injections at branding of 2 mL of clostridial, 5 mL of clostridial, vitamin AD3, and OTC caused injection-site lesions in 72.5, 92.7, 5.3, and 51.2%, respectively, of inside rounds from slaughter cattle. Incidence of injection-site lesions was lowest (P < .05) among inside rounds and top sirloin butts from animals given vitamin AD3 (as calves, and at both branding and weaning times) and was highest (P < .05) in inside rounds from cattle given, as calves, injections of 5 mL of clostridial at branding or of OTC at weaning. Less trimming was required to remove the lesions resulting from injections of all four products when they were given at weaning time. Before completion of the present study, it was thought that injection-site lesions were from damage that subsisted only briefly following an inoculation; these results make it abundantly clear that intramuscular administration of clostridials and certain antibiotics will cause damage so severe that it will be evident in beef muscle 7.5 to 12 mo later.

Use of epidemiologic principles to identify risk factors associated with the development of diarrhea in calves in five beef herds.

The objective of the study reported here was to identify and measure risk factors associated with the incidence of diarrhea in calves in 5 beef herds in North Dakota. Risk factors associated with calves developing diarrhea during the 1992 calving season were used to develop the following intervention strategies that were implemented during 1993: heifers calved in a separate location, diarrheal calves and their dams were placed in a quarantine area, and pregnant cattle were fed a diet supplemented with protein and copper. The risk of calves developing diarrhea was 5 times higher during the first year, compared with the second year, suggesting that the management changes made during the second year were contributing factors in reducing the percentage of calves with diarrhea. The risk of diarrhea developing in calves born to heifers was 3.9 times greater than that in calves born to cows. Analysis of our data indicated that the use of an epidemiologic approach can identify risk factors, which can lead to the development of intervention procedures that may decrease the incidence of diarrhea in calves in beef herds.

Comparison of four methods for forage nitrate analysis.

Twenty forage samples were collected and selected for variation in nitrate content. Each forage samples was analyzed 4 times by 4 different methods: diphenylamine spot plate, spectrophotometric, nitrate-selective electrode, and high-performance liquid chromatographic. Five feed extracts were spiked with 2 different amounts of nitrate and analyzed by each method. The spectrophotometric and nitrate-selective electrode had similar percent recoveries, which were close to 100%. The nitrate-selective electrode method had the least variation of the 4 methods. The diphenylamine spot plate method had the poorest average recovery, greatest variation, and was the least accurate. The average coefficients of variation for all samples within a method were 15%, 12%, 6.4%, and 16 for the diphenylamine spot plate, spectrophotometric, nitrate-selective electrode, and high-performance liquid chromatographic methods, respectively. The variation in the nitrate-selective electrode method was lower (P < 0.05) than the other methods. The results from this study suggest that the nitrate-selective electrode method is more accurate and precise than the other methods of analysis tested.

An increase in serum lipids increases luteal lipid content and alters the disappearance rate of progesterone in cows.

To determine whether an increase in serum lipids alters the area occupied by lipid droplets in steroidogenic luteal cells and(or) clearance rates of progesterone from serum, pregnant beef heifers received control (n = 6) or treatment (n = 5) diets. To increase serum lipids, the treatment diet contained calcium soaps of fatty acids. Control and treatment diets were formulated to be isocaloric and isonitrogenous. Feeding of diets was initiated approximately 100 d before parturition and continued through the third postpartum estrous cycle. On d 12 or 13 of the third postpartum cycle, corpora lutea were collected by ovariectomy and a center slice was processed for electron microscopy. Eight samples from each slice were sectioned, stained, and examined at a magnification of 2,500x. Five micrographs per sample were analyzed for area occupied by small (SLC) and large (LLC) luteal cells, percentage of the area of each steroidogenic cell type occupied by lipid, and total steroidogenic area (SLC + LLC) occupied by lipid. Jugular blood was collected before and after ovariectomy, and progesterone, cholesterol, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) were quantified. Cows consuming treatment diets had approximately twice (P < .05) the concentration of cholesterol, HDL, and progesterone in serum that controls had. The percentage of the area of SLC, LLC, and total area occupied by lipid was greater (P < .05) in treated than in control cows. The average time required for serum concentrations of progesterone to decrease by 50% after ovariectomy was greater (P < .05) in treated than in control cows (170 +/- 16 vs 113 +/- 15 min).(ABSTRACT TRUNCATED AT 250 WORDS)

Synchronization of estrus in suckled postpartum beef cows with melengestrol acetate and PGF2alpha.

A total of 402 two suckled postpartum beef cows at 2 locations (CSU and ECRC) were utilized in 3 trials to evaluate the effectiveness of a combination melengestrol acetate (MGA)-PGF2alpha estrus synchronization system in spring-calving cows. The cows were allocated by days post partum, body condition score (1 = emaciated; 9 = obese), sire breed, and dam age at the beginning of treatment to 1 of 2 treatments within location and trial: MGA-PGF2alpha (0.5 mg MGA/head/d for 14 d with 25 mg of PGF2alpha injected 17 d after MGA withdrawal), and unsynchronized controls. All cows were observed for estrus at 12-h intervals for at least 5 d post injection. Cows observed in standing estrus were inseminated 12 to 18 h later. There was a location effect on response to treatment that was attributed to differences in body condition score between locations so data were analyzed within a location. Body condition score at the CSU location was 5.7 compared with 4.0 at the ECRC location. The CSU MGA-PGF2alpha treated cows had higher (P < 0.05) 5-day estrus and 5-d pregnancy rates (78.6 and 61.0%, respectively) than the CSU controls (11.1 and 6.9%, respectively). Similar results for 5-d estrus and pregnancy rates but of decreased magnitude were also observed for the ECRC MGA-PGF2alpha treated (31.6 and 21.4%, respectively) cows compared with that of the ECRC controls (11.9 and 8.5%, respectively). The CSU MGA-PGF2alpha treated cows had higher (P < 0.05) 25- and 60-d pregnancy rates (82.5 and 94.8%) than the CSU controls (65.3 and 87.5%). The 25- and 60-d pregnancy rates were similar between the ECRC MGA-PGF2alpha treated cows and ECRC control cows. The MGA-PGF2alpha estrus synchronization system appears to contribute to pregnancy early in the breeding season in postpartum beef cows, although its effectiveness is limited by cow body condition.

Synchronization of estrus in suckled postpartum beef cows with melengestrol acetate, 48-hour calf removal and PGF2alpha.

One hundred and sixty-five suckled postpartum beef cows were utilized to evaluate the effectiveness of 2 estrus synchronization systems for the initiation and synchronization of estrus. The treatment groups consisted of 1) melengestrol acetate (MGA)-PGF2alpha (cows were given 0.5 mg MGA/head/day for 14 d with 25 mg PGF2alpha injected 17 d after the last day of MGA administration); 2) MGA-48-h calf removal (CR)-PGF2alpha (cows were given 0.5 mg MGA/head/day for 14 d with 48-h calf removal starting on the second day after completion of the MGA regimen plus 25 mg PGF2alpha administered 17 d after the last day of MGA); and 3) unsynchronized controls. Cows were assigned to treatments by the numbers of days post partum, body condition, age, and breed of sire. The cows were observed for estrus at 12-h intervals for 5 d after PGF2alpha administration and were artificially inseminated 12 to 18 h after the observed estrus. Both the MGA-PGF2alpha and MGA-CR-PGF2alpha treatments (64.8 and 61.8%) had greater (P < 0.05) 5-d estrus rates than the control treatments (34.5%). The synchronized pregnancy rate was greater (P < 0.05) for the MGA-CR-PGF2alpha than the control treatment.(52.7 vs 30.9%, respectively). The MGA-CR-PGF2alpha cows had a higher 25-d pregnancy rate than either the MGA-PGF2alpha (P < 0.05) or control cows (P < 0.08). Of the anestrous cows at the beginning of treatment, more MGA-CR-PGF2alpha (P = 0.1) and MGA-PGF2alpha cows were cyclic posttreatment than control cows (58.7 and 55.1 vs 44.7%, respectively), suggesting that treatment initiated estrous cycles in only a small number of the anestrous cows. Both MGA-PGF2alpha and MGA-CR-PGF2alpha treatments appear to be effective methods of synchronizing estrus in suckled postpartum beef cows. However, MGA-CR-PGF2alpha was more effective in establishing pregnancy earlier in the breeding season than MGA-PGF2alpha.

Comparison of two MGA-PGF2alpha systems for synchronization of estrus in beef heifers.

Yearling beef heifers (n=193) were used to evaluate reproductive performance attained with 2 MGA-PGF2alpha synchronization systems. These treatments were compared with an untreated control group. The 14-d MGA heifers were synchronized by feeding 0.5 mg MGA/h/d for 14 d. At 17 d after the last MGA feeding, these heifers were injected with PGF2alpha (25 mg, im). Heifers in the 7-d MGA treatment group were fed 0.5 mg MGA/h/d for 7 d and received a 25-mg, im injection of PGF2alpha on the last day of the MGA feeding period. Heifers in all 3 treatment groups were observed for estrus every 12 h for 7 d beginning 24 h after the PGF2alpha injection. Heifers observed in estrus during this 7-d period were artificially inseminated approximately 12 h after the onset of estrus. The percentages of heifers in estrus during the 7-d synchronized period were 75.4, 56.3 and 17.2% for the 14-d MGA, 7-d MGA and control groups, respectively. The estrous responses were significantly different in each treatment. The percentage of heifers in estrus during the peak 24-h period was higher (P<0.05) in heifers synchronized with the 14-d MGA system than in heifers synchronized with the 7-d MGA system (75.5 vs 50.0%). The synchronized conception rate of the 14-d MGA heifers was significantly higher (65.3%) than that of both the 7-d MGA (41.7%) and control (45.4%) heifers. Synchronized conception rates were similar (P=0.79) in the 7-d MGA and control treatments. Synchronized pregnancy rates were 55.2, 32.4 and 15.2% for the 14-d MGA, 7-d MGA and control groups, respectively. Both synchronization treatments resulted in significantly higher synchronized pregnancy rates compared with that of the controls. The synchronized pregnancy rate was higher (P<0.05) in the 14-d MGA group than it was in the 7-d MGA group. The mean day of conception within the breeding season was 11.5 and 9.3 d shorter in the 14-d MGA heifers than in the 7-d MGA and control heifers, respectively. Our results indicate that using the 14-d MGA system to synchronize estrus in beef heifers results in better reproductive performance than that attained in heifers synchronized with the 7-d MGA system or in control heifers.

Comparison of timed insemination with insemination at estrus following synchronization of estrus with a MGA-prostaglandin system in beef heifers.

Three trials utilizing 231 beef heifers were conducted in 1993 to determine if a timed insemination would result in similar synchronized pregnancy rates as insemination by estrus following synchronization of estrus using the 14-d MGA-prostaglandin system. All heifers were fed 0.5 mg MGA/h/d fof 14 d and given a 25 mg injection of PGF(2)alpha im 17 d after the final day of MGA feeding. Heifers in Group 1 (timed AI treatment) were inseminated at 72 h after the prostaglandin injection independent of whether or not they were observed in estrus. Heifers in Group 2 (AI by estrus) were inseminated 12 to 18 h after the onset of estrus. Since the trial was a significant source of variation for synchronized pregnancy rate, the effect of treatment on pregnancy rate was analyzed for each trial. Synchronized pregnancy rates in Trials 2 and 3 were similar in both treatment groups; 37 vs 35% and 61 vs 58% for the timed AI vs AI by estrus (Groups 1 and 2) in Trials 2 and 3, respectively. In both of these trials the degree of estrous synchrony was high. In Trial 1, the synchronized pregnancy rate in heifers that were time-inseminated was significantly lower than that of heifers that were inseminated by estrus (29 vs 57%). The lower synchronized pregnancy rate of Group 1 (timed AI) heifers in Trial 1 appeared to be due to the low degree of estrous synchrony in this trial. Our results indicate that using timed insemination with the 14-d MGA-prostaglandin system will give similar synchronized pregnancy rates as inseminating by estrus in groups of beef heifers where the degree of synchrony is high. However, in heifers where the degree of estrous synchrony is low, a timed insemination reduces synchronized pregnancy rates.

Causes and costs of calf mortality in Colorado beef herds participating in the National Animal Health Monitoring System.

Seventy-three Colorado cow/calf operations were monitored for calf mortality from birth to weaning as part of their participation in the National Animal Health Monitoring System. Producer-observed causes of calf mortality, and the costs associated with these deaths were obtained. The overall calf mortality during the study was 4.5%, with a total associated cost of $237,478. The mean cost per calf death was $216, of which $208 was attributed to the potential value of the calf and an additional $8 was for veterinary, drug, producer's labor, and carcass disposal expenses. The most commonly reported causes of calf mortality were dystocia (17.5%), stillbirth (12.4%), hypothermia (12.2%), diarrhea (11.5%), and respiratory infections (7.6%). These 5 disease conditions accounted for > 60% of all calf deaths. A cause was not determined for 19.7% of the calf deaths. Beef producers and veterinarians have the potential to decrease calf mortality and increase profits in cow/calf operations by implementing management strategies and herd health programs designed to decrease the number of calf deaths caused by these disease conditions.

Factors contributing to dystocia due to fetal malpresentation in beef cattle.

Records on 3873 calvings over a 21-year period (1971 to 1991) from the Colorado State University Resident Instruction beef cattle herd were used to examine factors associated with malpresentations at birth. Approximately 82% of the calvings were unassisted and 18% were assisted in some manner. Of the assisted deliveries, severe traction, mild traction, malpresentation and caesarean section accounted for 44.5, 31.8, 22.4 and 1.3%, respectively, of the total. Ninety-six percent of all births were normal presentations and 4% were malpresentations. The incidence of malpresentations was affected by year, sex of calf, and sire of calf within breed. Most of the malpresentations were in the posterior dorsal position (72.8%) followed by unilateral carpal or shoulder flexion (11.4%), breech (8.2%), lateral deviation of the head (2.5%), incomplete extension of the elbow (1.9%), posterior ventral (1.3%), transverse (1.3%) and oblique ventro-vertical (0.6%). Factors influencing the incidence of posterior dorsal presentations were year, sex of calf, sire of calf within breed, and age of dam. Malpresentation heritability estimates as traits of the calf were 0.088 and 0.003 for Hereford and Angus breeds, respectively. Posterior presentation heritability estimates for Hereford and Angus cattle were 0.173 and 0.0, respectively. Heritabilities as traits of the dam and repeatabilities for malpresentation, and posterior presentation were minimal.

Relationship of maternal milk expected progeny differences to actual milk yield and calf weaning weight.

Calf weaning weights and estimates of 205-d milk yield (n = 317) were obtained from 90 Polled Hereford (PH) and 80 Simmental (SM) cows to evaluate the relationship of these measures with maternal milk and total maternal EPD from national cattle evaluations. An inverse parabolic exponential function predicted 205-d milk yields for each cow from five estimates of daily milk yield taken once per month via calf weigh-suckle-weigh. Changes in calves' 205-d adjusted weights were greater than predicted (P < .02) by maternal milk EPD of PH and SM dams and PH maternal grandsires (MGS) but were similar to changes predicted by SM MGS (P > .50). These changes were also greater than those predicted by total maternal EPD of PH dams and MGS (P < .02) but were similar to those predicted in SM dams and MGS (P > .38). Interactions of maternal milk and total maternal EPD with sex of calf and year did not influence calves' 205-d adjusted weights (P > .10). A positive relationship was found in both breeds between 205-d milk yield EPD (calculated from 205-d milk yield estimates) and maternal milk EPD from national cattle evaluations. Objectively assessing the magnitude of this relationship was hindered by problems in estimating heritability and interpreting correlations between EPD. These data indicate that maternal milk and total maternal EPD from national cattle evaluations are reasonably good predictors of genetic differences in milk yield and weaning weight.

Physiologic differences between twin and single born beef calves in the first two days of life.

Behavioral observations and hematological, serum biochemical and blood gas measurements were made on 8 naturally occurring twin calves during the first 48 hours of life. These values were compared to similar measurements collected from 30 single born calves, born under the same calving conditions. All calves survived to at least 3 weeks of age without physically detectable disease. Although the gestational age of the twins and singles were not different, the twins had a lower mean birth weight. Calving difficulty score, time interval to standing and time interval to nursing were not different between the 2 groups. Twin calves had significantly lower rectal temperatures, arterial oxygen tensions and blood glucose concentrations than the single calves through the first 12 hours of life. Hct, Hgb concentration, and RBC were lower in twin calves throughout the 48 hour period. The N:L ratio was lower in the twins at birth. Mean serum IgG1 concentrations were lower in twins only at 24 hours whereas IgM concentrations were lower at both 24 and 48 hours in twins. Serum chemistry value differences between twin and single calves were most numerous at 24 hours of age when serum proteins, urea nitrogen, total bilirubin, sodium, chloride, and total calcium concentrations were higher in the twins and serum phosphorus concentration was lower in the twins.

Hematologic values in newborn beef calves.

Hematologic values were determined in 35 beef calves at birth, at 24 and 48 hours, and in 22 of these calves at 3 weeks after birth. Thirty calves did not have clinical signs of disease throughout the 3-week period. Variables that changed significantly over time in these healthy calves included hematocrit, RBC count, hemoglobin concentration, mean cell volume, mean cell hemoglobin concentration, WBC count, neutrophil-to-lymphocyte ratio, and plasma total protein and serum immunoglobulin concentrations. Of the 35 calves, 5 had clinical signs of disease at 3 weeks. Comparison of hematologic values from these calves with values for healthy calves revealed significant differences at each sample collection time, although disease was not evident at the 3 early sample times. The band neutrophil count and the neutrophil-to-lymphocyte ratio differed between the 2 groups at birth. At 24 hours, the monocyte count was higher in the 5 ill calves. At 48 hours, total leukocyte, mature neutrophil, and monocyte counts, and neutrophil-to-lymphocyte ratio also were higher in the 5 calves. At 3 weeks when clinical signs of disease were detectable in the 5 calves, the total leukocyte, band neutrophil, and mature neutrophil counts, neutrophil-to-lymphocyte ratio, and plasma total protein and fibrinogen concentrations were higher.(ABSTRACT TRUNCATED AT 250 WORDS)

Costs of veterinary services and vaccines/drugs used for prevention and treatment of diseases in 86 Colorado cow-calf operations participating in the National Animal Health Monitoring System (1986-1988).

Eighty-six cow-calf operations involved in the Colorado National Animal Health Monitoring System were monitored for a 12-month period, and data were collected on the incidence, prevention, and costs of disease. The costs of veterinary services and vaccines/drugs used in the treatment and prevention of disease conditions in these beef herds were determined and expressed on a per cow basis. Beef producers in this study spent an average of $2.04 ($0 to $29.88) per cow annually on veterinary services for treatment of disease conditions. The cost of veterinary services was a relatively small percentage (5.4%) of the total mean cost of disease incidence. The reproductive tract disease class was the most costly class in terms of veterinary services for disease treatment ($0.99/cow). Dystocia was the disease condition with the largest veterinary treatment cost. The total mean annual cost of drugs used in the treatment of disease conditions was $1.22/cow. The enteric, miscellaneous, and respiratory tract disease classes had similar mean drug costs for disease treatment and ranged from $0.31 to $0.39/cow. The total mean annual cost of veterinary services for administration of preventive measures in these herds was $1.85/cow ($0 to $12.03). Pregnancy examination, breeding soundness examination in bulls, brucellosis vaccination, pulmonary arterial pressure test, and campylobacteriosis vaccination accounted for over 90% of the money spent for preventive veterinary services. Approximately 60% of the total mean annual disease prevention cost was attributed to the purchase of vaccines/drugs ($6.59/cow).(ABSTRACT TRUNCATED AT 250 WORDS)

Annual costs associated with disease incidence and prevention in Colorado cow-calf herds participating in rounds 2 and 3 of the National Animal Health Monitoring System from 1986 to 1988.

Thirty-nine and 47 randomly selected Colorado cow-calf operations were monitored for health events and their associated costs during rounds 2 and 3, respectively, of the National Animal Health Monitoring System (NAHMS). Data were collected from each operation for a one-year period by NAHMS veterinarians through monthly interviews, and the costs associated with the incidence and prevention of disease conditions were determined and expressed on a per cow basis. The beef producers involved in this study spent an average of $32.75 per cow in round 2 and $40.97 per cow in round 3 on an annual basis for the treatment of disease conditions. These costs were not different between the 2 rounds because of the wide ranges in the individual herd costs for disease incidence in each round. In both years of the study, the largest contributor to the total mean annual cost of disease incidence was the cost of death of diseased animals, and this cost accounted for approximately two-thirds of the total mean annual cost in each round. The total mean annual costs of disease prevention in these herds were $11.24 and $11.19 per cow in rounds 2 and 3, respectively. There were wide ranges in both rounds in the amounts of money spent per cow by individual herds for disease prevention. The largest individual cost of disease prevention in each year was the cost of vaccines/drugs, whereas the smallest individual cost in each round was the cost of veterinary services.(ABSTRACT TRUNCATED AT 250 WORDS)