Effects of twinning on gestation length, retained placenta, and dystocia.
(9/4595)
Constraints to maximal productivity from twinning in beef cattle include increased incidence of dystocia and retained placenta, longer postpartum interval, and lower conception rate. Incidence and cause(s) of the shorter gestation length and of the increased retained placenta and dystocia associated with twinning were evaluated for 3,370 single and 1,014 twin births produced in a population of cattle selected for natural twin births. Gestation length was shorter for twin than for single pregnancies (275.6 vs. 281.3 d, P<.01) and likely contributed to the higher incidence of retained placenta associated with twin births (27.9 vs. 1.9%; P<.01). Incidence of retained placenta was also higher in the spring (March-April) than in the fall (August-September) calving season (18.3 vs. 11.4%; P<.01). The higher incidence of dystocia with twins than with singles (46.9 vs. 20.6%, P<.01) was primarily due to abnormal presentation (37.0 vs. 4.5%, respectively) of one or both twin calves at parturition. First- (40.5%) and second- (22.7%) parity dams with a single birth had more (P<.01) dystocia than older dams (13.4%), whereas dystocia was not affected (P>.10) by parity with twin births. Because of the shorter gestation length and the increased incidence of retained placenta and(or) dystocia, achievement of increased productivity with twinning in cattle necessitates intensive management of twin-producing dams and their calves during the calving season. Management of the increased dystocia can be facilitated by preparturient diagnosis of twin pregnancies, enabling timely administration of obstetrical assistance to facilitate delivery of twin calves and to increase their neonatal survival. (+info)
The effects of low-copper diets with or without supplemental molybdenum on specific immune responses of stressed cattle.
(10/4595)
Angus bull calves (n = 42; 7 mo of age; 254 kg initial BW) were used to investigate the effects of dietary Cu and Mo on immune function of stressed cattle. Randomly selected calves (n = 22) were injected with 90 mg of Cu as Cu glycinate 28 d before weaning and castrated at weaning. These calves received 7.5 and 5 mg of supplemental Cu/kg of DM during a 41-d receiving phase and a 196-d growing phase, respectively. The remainder of the steers received no supplemental Cu during the experiment. Copper-supplemented steers had adequate Cu status at weaning, whereas unsupplemented calves were marginally Cu-deficient. Cell-mediated response to intradermal injection of phytohemagglutinin was not affected by dietary treatment during the receiving phase. During the growing phase, half of the steers in each Cu treatment were given 5 mg of supplemental Mo/kg of DM. Copper supplementation increased (P<.05) humoral response to ovalbumin injected on d 133 of the growing phase. On d 168 of the growing phase, calves receiving only supplemental Mo were severely Cu-deficient based on plasma and liver Cu concentrations. The other treatment groups had adequate Cu status. Before feeding on d 168 of the growing phase, half of the steers were loaded onto trailers and transported 2.5 h, and they remained on the trailers an additional 9.5 h. Humoral response to porcine erythrocytes (PRBC) and delayed-type hypersensitivity (DTH) to dinitrochlorobenzene was tested at the end of the stress period. There was a Cu x stress interaction for humoral response to PRBC, with Cu decreasing antibody titers in unstressed calves and increasing titers in stressed steers. Stressed steers had lower (P = .03) ADG during the 28 d following stress. The results of this study indicate that Cu deficiency and 5 mg of supplemental Mo/kg of DM do not dramatically alter the specific immunity of stressed cattle. (+info)
Rotavirus G-type restriction, persistence, and herd type specificity in Swedish cattle herds.
(11/4595)
G-typing of rotavirus strains enables the study of molecular epidemiology and gathering of information to promote disease prevention and control. Rotavirus strains in fecal specimens from neonatal calves in Swedish cattle herds were therefore characterized by using G1 to -4-, G6-, G8-, and G10-specific primers in reverse transcription (RT)-PCR. Fecal samples were collected from one dairy herd (herd A) for 4 consecutive years and from 41 beef and dairy herds (herd B) experiencing calf diarrhea outbreaks. Altogether, 1, 700 samples were analyzed by group A rotavirus enzyme-linked immunosorbent assay, and 98 rotavirus-positive specimens were selected for G-typing by RT-PCR. The effect of herd type, time, geographic region, and clinical symptoms on the G-type distribution was evaluated. Altogether (herds A and B), G10 was found in 59 (60. 2%) fecal specimens, G6 was found in 30 (30.6%) specimens, G3 was found in 1 (1.0%) specimen, and G8 was found in 1 (1.0%) specimen. Seven (7.1%) fecal specimens were not typeable. Herd type specificity in the G-type distribution was demonstrated in the herds in herd B. In the 6 beef suckler herds, only G6 was detected, while rotavirus strains from the 35 dairy herds were predominantly (54%) G10. The G-type distribution was restricted in herds A and B. Twenty-nine of 30 strains from herd A were characterized as G10. In the vast majority of herds in herd B, a single G-type was identified. The serotype G10 and the electropherotype persisted over time in herd A. No characteristic G-type variation in the geographic distribution of cattle herds in herd B was obvious. There was no difference in the G-type distributions between the strains from clinically and subclinically rotavirus-infected calves in dairy herd A. The results from this study strongly indicate a pronounced stability in the rotavirus G-type distribution in Swedish cattle herds, which emphasizes the importance of continuous preventive measures for control of neonatal calf diarrhea. A future bovine rotavirus vaccine in Sweden should contain G10 and G6 strains. (+info)
Epithelial thyroid tumors in cows.
(12/4595)
From 1964 to 1973, 370 tumors were collected from cows of unknown age. Ten (2.7%) of these were primary thyroid tumors. Three were malignant. The benign tumors were solitary encapsulated adenomas in the parenchyma with more or less defined trabeculae, tubular, and microfollicular pattern. One of the malignant tumors was a cystic papillary adenocarcinoma, and two were small cell carcinomas consisting of small, sometimes binuclear, pleomorphic cells. (+info)
Delayed osteon formation in long-bone diaphysis of an 11-year-old giant cow with dermal dysplasia.
(13/4595)
The transverse sections of radius diaphysis in an 11-year-old giant Holstein cow with dermal dysplasia of a collagen disorder-related skin fragility (Cow 1), probably based on increasing turnover of the dermal collagen as reported previously, were morphologically and physico-chemically investigated. Cow 1 had about one and a half times as much as the body weight of normal Holstein cows, aged 5 to 6.5 years with stabilized growth. The bone samples were compared with those of a 12-year-old Holstein cow as controls (Cow 2). It has been reported that the long-bone diaphysis of young calves and some herbivorous dinosaurs are occupied with laminar bone showing a concentric appositional formation, and that such a laminar bone is characteristically seen during the growing period of some farm animals and large dogs that show very rapid growth rates. Cow 1 had a smaller number of osteons than Cow 2 in the outer-half layer of the diaphysis, and showed an intermediate type between Cow 2 and a 1-year-old Holstein ox in the entire layers, although their bone volumes were similar among them. There were no significant differences in Ca and P concentrations and the Vickers microhardness values between the bone matrix of Cow 1 and Cow 2. The bone-collagen fibrils of Cow 1 showed uneven diameters and a disordered arrangement. Thus, there may be some relation in collagen formation between the bone matrix of Cow 1 and the dermis. From the remaining volume of laminar bone, Cow 1, aged 11 years, had probably shown growth until quite recently, so that we consider that Cow 1 became a giant animal, in the same way as some herbivorous dinosaurs. (+info)
Human echinococcosis in Bulgaria: a comparative epidemiological analysis.
(14/4595)
The present article describes the importance of human echinococcosis as a public health problem in Bulgaria, outlines the control measures carried out and evaluates comparatively the situation over three periods spanning 46 years (1950-1995). During the first period (1950-62), a total of 6469 new surgically confirmed cases of hydatid disease were recorded in Bulgaria, with an annual incidence of 6.5 per 100,000 population, and the infestation rate in domestic animals and dogs was high. Echinococcosis was endemic throughout the country. The organization of a control campaign, initiated in 1960, led to a considerable improvement in the situation during the second period (1971-82). Morbidity among humans gradually decreased, with an average incidence of 2.0 per 100,000, and the proportion of infected animals also fell. The distribution of echinococcosis was characterized as sporadic or of low endemicity. During the third period (1983-95), owing to administrative irregularities and economic changes, funds for supporting the campaign were reduced and control structures were dismantled. As a result, the incidence rose to 3.3 per 100,000. Echinococcosis again became endemic, in some regions hyperendemic. The findings provide convincing evidence that cessation of control measures or reduction of campaign activity can lead to intensification in the transmission of Echinococcus granulosus and to a resurgence in echinococcosis to previous levels. (+info)
Antigen-specific B-cell unresponsiveness induced by chronic Mycobacterium avium subsp. paratuberculosis infection of cattle.
(15/4595)
Mycobacterium avium subsp. paratuberculosis infection of cattle results in a chronic granulomatous enteritis. Clinical disease (i.e., cachexia, diarrhea, and high fecal bacterial counts) is preceded by a lengthy subclinical stage of disease. The immunologic mechanisms associated with the progression of infected cattle from subclinical to clinical disease are unclear. In this study, a cell proliferation assay was used in combination with flow cytometry to compare peripheral blood lymphocyte responses of cattle with subclinical paratuberculosis to responses of cattle with clinical paratuberculosis. B cells from cattle with subclinical disease proliferated vigorously upon stimulation with M. avium subsp. paratuberculosis antigen, with up to 12.4% of the total B cells responding. However, B cells from cattle with clinical disease did not proliferate upon antigen stimulation despite good proliferation in response to concanavalin A stimulation. In addition, these animals had high percentages of peripheral blood B cells. B cells from noninfected animals did not proliferate upon M. avium subsp. paratuberculosis antigen stimulation. Thus, it appears that B-cell proliferation is a sensitive indicator of subclinical Johne's disease. Furthermore, the immunologic mechanisms responsible for the antigen-specific unresponsiveness of peripheral blood B cells may be significant in the eventual progression from subclinical to clinical Johne's disease in cattle. (+info)
Evidence of partial protection against foot-and-mouth disease in cattle immunized with a recombinant adenovirus vector expressing the precursor polypeptide (P1) of foot-and-mouth disease virus capsid proteins.
(16/4595)
A recombinant live vector vaccine was produced by insertion of cDNA encoding the structural proteins (P1) of foot-and-mouth disease virus (FMDV) into a replication-competent human adenovirus type 5 vaccine strain (Ad5 wt). Groups of cattle (n = 3) were immunized twice, by the subcutaneous and/or intranasal routes, with either the Ad5 wt vaccine or with the recombinant FMDV Ad5-P1 vaccine. All animals were challenged by intranasal instillation of FMDV 4 weeks after the second immunizations. In the absence of a detectable antibody response to FMDV, significant protection against viral challenge was seen in all of the animals immunized twice by the subcutaneous route with the recombinant vaccine. The observed partial protection against clinical disease was not associated with a reduction in titre of persistent FMDV infections in the oropharynx of challenged cattle. (+info)