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PubMed1976

A study of nephritis of beef cattle in North Queensland.

The incidence of subclinical nephritis in beef cattle slaughtered at a Townsville abattoir during the period 1970-73 was 3.8 percent. A rising incidence coincided with the wet summer of 1973-74 reaching a peak of 8.2 percent thereafter in June 1974. All but 1 of 100 cases macroscopically identified as nephritis and studied histologically proved to be of interstitial type in which lymphocytic infiltration predominated. Follicular lymphoid hyperplasia was also a common feature. The exceptional case showed proliferative glomerulonephritis. Leptospires were isolated from 16 percent of cases cultured, and observed in 8 percent of specimens examined histologically. All of the 8 isolates subjected to serogrouping were L. pomona. Of the animals tested serologically against 2 serotypes 66.2 percent were positive to L. pomona (33.8 percent), L. hardjo (18.9 percent) or both (13.5 percent). The total incidence is significantly higher than in other random surveys carried out in the region. These findings suggest that Leptospira sp. are a major cause of bovine nephritis. Since other pathogens endemic in the area, for example, Babesia and Theileria sp., may be capable of causing nephritis in cattle an accurate assessment of the aetiology of that form of renal disease in north Queensland cannot yet be made.

Agglutinins↗
PubMed1981

Beef cattle research in the next decade.

Priorities for research in beef cattle are proposed in the areas of nutrition, breeding, reproduction and health. Research in nutrition should be concerned with enhancing utilisation of cellulose and non-protein nitrogen. Cattle breeding projects should concentrate on the synthesis of genotypes suited to specific environments, while in the area of reproduction, wastage remains the most important problem. Improvement of diagnostic tests and vaccines would result from intensified research into subcellular function of causative organisms. Major contributions to animal health could emanate from studies of the genetic basis of disease resistance. The very small number of veterinarians employed in animal production research tends to deprive health of its proper place as a central feature of production.

Animal Nutritional Physiological Phenomena↗
PubMed1976

Effect of short-chain Fatty acids extracted from beef cattle manure on germination and seedling development.

Composted and fresh beef cattle manure samples were extracted with distilled water, acetone, methanol, 2 N sodium hydroxide, 2 N hydrochloric acid, and ether. Bioassay techniques, using the extracts, showed that composted manure extracts had limited effect on seed germination and seeding development of wheat and sorghum. All the extracts of fresh manure, other than distilled water, retarded germination. Acetic, butyric, propionic, valeric, and isovaleric acids were found in ether extracts of fresh manure at average concentrations of 348, 876, 578, 34, and 19 mug/g, respectively, on a dry-weight basis. However, only trace amounts of these acids were present in composted manure. Propionic acid up to the 200-mug/ml level stimulated seedling growth. Acetic and butyric below the 200-mug/ml level had no detrimental or beneficial effects on seedling development. When acetic, butyric, and propionic acids were mixed in equal parts, germination and seedling growth were reduced at all levels (50 to 500 mug/ml).

Journal Article↗
PubMed1998

Eosinophilic proliferative pylephlebitis in the liver of Japanese beef cattle with fascioliasis.

Intrahepatic pylephlebitis was detected in 17 Japanese beef cattle. Grossly, the intrahepatic vessels in the caudate lobe and/or in the periphery of the other hepatic lobes were thickened and protruded above the lobar surface. The vessel lumina were packed with white to red, waste thread-like contents. A few immature flukes were found in the bile ducts in 3 of the 7 cases with biliary thickening. Foci of hepatic necrosis and hemorrhage were scattered around the thickened vessels in 8 cases. Histologically, the interlobular veins were thickened due to severe intimal hyperplasia with endothelial proliferation and eosinophilic accumulation and medial hypertrophy, accompanied by fibrosis and eosinophilic infiltration in the portal areas. Hepatic tissues with necrosis and hemorrhage were surrounded by eosinophils and histiocytes including a granulomatous reaction. One immature fluke was detected in one of these regions of necrosis. Immunoperoxidase staining revealed that the small fluke, Kupffer cells, and histiocytes in the liver of all cases were positively stained with anti-Japanese Fasciola sp. antiserum. Enzyme-linked immunosorbent assay of the sera of 15 cases revealed that all were positive for the anti-Fasciola antibody. On the basis of these findings, the present cases were regarded as an atypical form of fascioliasis, characterized by eosinophilic proliferative pylephlebitis of the liver.

Animals↗
PubMed1983

Calving date versus calving interval as a reproductive measure in beef cattle.

Calving date and calving interval records obtained from the Beef Cattle Division of Pioneer Hi-Bred International, Des Moines, Iowa, were studied to determine the reproductive measure of choice when a fixed breeding season is employed. Fixed model, least-squares procedures were used to analyze 2,411 records collected on purebred Red Angus, Angus and Hereford cows during the years 1969 through 1976. Calving interval decreased .86 d and calving date was delayed .11 d for each 1-d delay in previous calving date. A 1-d increase in gestation length was associated with a 1.17-d delay in calving date and 1.17-d increase in calving interval. The bias caused by the use of a fixed breeding season was determined to be much greater for calving interval than for calving date, as evidenced by the strong dependence of calving interval on previous calving date. Because calving date is likely to be more heritable and has clear economic significance, and because selection for earlier calving date should not lead to adverse response in other reproductive traits, calving date was preferred over calving interval as a reproductive measure.

Analysis of Variance↗
PubMed2004

Salt poisoning in beef cattle.

Salt poisoning has been described under various circumstances in adult cattle. Presenting clinical signs in 6 Holstein beef cattle with such poisoning were primarily dysfunction of the central nervous system and included ataxia, opisthotonus, nystagmus, depression, muscle twitching and intermittent convulsions, as well as abdominal pain and polydipsia. Diarrhea occurred in 2, and blindness in 3/6 cattle. Hypernatremia (161.8 - 178.8 mmol/L) and hyperosmolality (331.81 - 366.18 mOsm/L) were present in all animals. To treat the affected cattle, access to fresh water was restricted, vascular volume was expanded with isotonic saline and then hypotonic fluid (5% Dextrose solution) i.v. and dexamethasone im was administered. Although biochemical parameters returned to normal reference ranges, 3/6 affected animals remained blind.

Animals↗
PubMed2000

Technical note: covariance adjustment in beef cattle research.

In randomized experiments, analysis of covariance is used to increase precision of treatment comparisons. However, for factors that are observational (e.g., breed) or for covariates measured after treatments are applied, it may not be biologically meaningful to calculate treatment means adjusted to a common value of the covariate. For example, in beef cattle trials, it may not be meaningful to compare hot carcass weights of medium- and large-framed breeds adjusted to a common weaning weight because the breeds have naturally different mean weights at weaning. If done, this would typically result in an undesirable downward adjustment of mean carcass weight for the large-framed breed and upward adjustment of the mean carcass weight for the small-framed breed. However, it is desirable to evaluate the mean carcass weight for two diets, adjusted to a common weaning weight. Because of randomization, the expected weaning weights of animals on the two diets are equal and hence the only effect of covariance adjustment is to increase precision of the diet comparison. This paper presents the statistical methodology for estimating covariance adjusted means (termed partially adjusted means) when the levels of some of the factors are compared at a common value of the covariate but the levels of other factors are compared at differing values of the covariate. The methodology is extended to include several covariates, several factors, and arbitrary interactions among covariates, among factors, and between factors and covariates. These methods can be implemented using existing statistical software for linear models. Data are presented from an experiment in which hot carcass weight was recorded for beef cattle. Analyses of these data illustrate that adjusted means, partially adjusted means, and unadjusted means may differ substantially in magnitude, significance, and in the ranking of treatments.

Analysis of Variance↗
PubMed1998

Experiential learning in the animal sciences: effect of 13 years of a beef cattle management practicum.

As the source of students shifts from rural to urban and suburban communities, students entering agricultural programs have less practical livestock experience. The career goals indicated by most of these students require knowledge of and experience with practical applications of their course work. The objective of this study was to examine the profile of students enrolled in an experiential beef cattle course 1) to describe the demographic and occupational characteristics of students enrolled and 2) to assess the perceived value of course activities to graduates completing the course as related to their skill attainment and career development. The questionnaire was sent to all 312 students who were enrolled in the course from 1983 to 1996. Over 61% of the respondents indicated they had enrolled in the course to gain experience working with beef cattle. Over 39% took the course to enhance their application to the College of Veterinary Medicine. When asked to rate the value of the course, as it related to skill development, they noted it was most helpful in teaching cattle handling skills, growth performance measurement, live animal evaluation, nutritional management, carcass and meat product value determination, and breed identification.

Animal Husbandry↗
PubMed2002

Fetal infection with Neospora caninum in dairy and beef cattle in Belgium.

Neospora caninum is a protozoan parasite, which causes fetal and neonatal mortality in livestock and companion animals. In 224 abortions in Belgian cattle, different diagnostic methods were used to demonstrate infection, and the presence of N. caninum. An indirect fluorescent antibody test (IFAT) was used to analyze fetal and maternal sera and immunohistochemistry (IHC) was performed when lesions consistent with neosporosis were observed in the brain, heart or liver. Twenty dairy cattle sera out of 70 (29%) and 13 beef cattle sera out of 93 (14%) were positive by IFAT. A positive titer to N. caninum was found in seven and three fetuses born to beef and dairy cows, respectively. Lesions consistent with N. caninum infection were observed in 17 fetuses. Of nine positive beef fetuses, five were confirmed by IHC while, all but one dairy fetus were confirmed using the same technique. Age had no influence on the serological status of the mother (P = 0.486) whereas husbandry system had a borderline influence (P = 0.082). However, a strong association (P = 0.004) between the level of antibodies in the dam and the occurrence of lesions in the fetus was observed and lesions were more prominent in dairy than in beef fetuses. Additionally, the distribution of intra-cerebral lesions was more extensive in dairy than in beef fetuses (P < 0.0001). Age and serological status of the fetus were found to influence the occurrence of lesions in beef fetuses (both P < 0.001) but no such significant relationships could be demonstrated in dairy fetuses. The study indicated that N. caninum must be considered as an important cause of bovine abortion in Belgium.

Abortion, Veterinary↗
PubMed1989

Characterization of some parameters of non-specific immunity in beef cattle (II).

Serum protein, immunoglobulins, complement, lysozyme, serum bactericidal activity and blast transformation of peripheral blood lymphocytes were tested in beef cattle in different herds and age groups. These parameters were evaluated in their time-kinetics, in comparison with age-matched groups of dairy cattle. Like dairy calves, beef calves up to 4 months of age were shown to have low levels of serum bactericidal activity and haemolytic complement; besides, a worse profile was detected in serum protein and gamma 2 globulin levels. Al(OH)3 and oil-adjuvanted vaccines had a favourable influence on immunoglobulin and lysozyme synthesis. An acute stressing event like transportation was shown to decrease mitogen-driven lymphocyte stimulation for at least 10 days after arrival.

Animals↗
PubMed2005

Analysis of female reproductive traits in Angus beef cattle divergently selected for blood serum insulin-like growth factor I concentration.

Insulin-like growth factor-I (IGF-I) is an anabolic polypeptide involved in reproductive performance in several species. The objectives of this study were to determine relationships of pregnancy rate, and age of heifers at puberty and at first calving with serum IGF-I concentration in Angus beef cattle. Data were obtained from an ongoing divergent selection experiment for IGF-I concentration involving purebred Angus cows. The IGF-I concentrations measured at Days 28, 42, and 56 of the 140-day postweaning test are abbreviated as IGF28, IGF42, and IGF56, respectively. Pregnancy rate did not differ between high and low IGF-I line females (P=0.95; n=2618), but high line heifers tended to be 4.02+/-2.18 days younger (P=0.07; n=281) at first calving. Residual correlations of age of heifers at first calving (AFC) with IGF-I measurements were not significant. The linear and quadratic terms for regression of AFC on IGF-I concentrations were also non-significant. Contrast analysis showed no difference in age at puberty between the high and low IGF-I line heifers (5.3+/-6.4 days earlier in the high line; P=0.43; n=51). Residual correlations of age of heifers at puberty with IGF28, IGF42, IGF56, and mean IGF-I were -0.30 (P=0.03), -0. 22 (P=0.12), -0.35 (P=0.01), and -0.34 (P=0.01), respectively. The observed relationships between female reproductive traits and IGF-I concentration in Angus beef cattle suggest complex and multiple roles for IGF-I in reproduction.

Aging↗
PubMed2006

Nitrogen and phosphorus status of soils and trophic state of lakes associated with forage-based beef cattle operations in Florida.

Forage-based livestock systems have been implicated as major contributors to deteriorating water quality, particularly for phosphorus (P) from commercial fertilizers and manures affecting surface and ground water quality. Little information exists regarding possible magnitudes of nutrient losses from pastures that are managed for both grazing and hay production and how these might impact adjacent bodies of water. We examined the changes that have occurred in soil fertility levels of rhizoma peanut (Arachis glabrata Benth.)-based beef cattle pastures (n = 4) in Florida from 1988 to 2002. These pastures were managed for grazing in spring followed by haying in late summer and were fertilized annually with P (39 kg P2O5 ha(-1)) and K (68 kg K2O ha(-1)). Additionally, we investigated trends in water quality parameters and trophic state index (TSI) of lakes (n = 3) associated with beef cattle operations from 1993 to 2002. Overall, there was no spatial or temporal buildup of soil P and other crop nutrients despite the annual application of fertilizers and daily in-field loading of animal waste. In fact, soil fertility levels showed a declining trend for crop nutrient levels, especially soil P (y = 146.57 - 8.14 x year; r2= 0.75), even though the fields had a history of P fertilization and the cattle were rotated into the legume fields. Our results indicate that when nutrients are not applied in excess, cow-calf systems are slight exporters of P, K, Ca, and Mg through removal of cut hay. Water quality in lakes associated with cattle production was "good" (30-46 TSI) based on the Florida Water Quality Standard. These findings indicate that properly managed livestock operations may not be major contributors to excess loads of nutrients (especially P) in surface water.

Agriculture↗
PubMed2002

Effects of supplemental vitamin E on performance, health, and humoral immune response of beef cattle.

Three experiments were conducted to examine the effect of dietary vitamin E on receiving performance and health and on finishing performance of beef cattle. One hundred twenty beef steers (Exp. 1; initial BW = 173 kg) and 200 beef heifers (Exp. 2; initial BW = 204 kg) were assigned randomly to one of three treatment diets formulated to supply 285, 570, or 1,140 IU/animal daily of supplemental vitamin E during the receiving period. Average daily gain, gain:feed, and DMI were calculated every 14 d, with pen as the experimental unit. Morbidity and retreatment data were analyzed using a nonparametric procedure. After the receiving period, cattle were assigned to a grazing period followed by a finishing program and fed until slaughter. In Exp. 3, 17 beef steers were used to evaluate effects of the same three vitamin E levels on humoral immune response to an ovalbumin vaccine given on d 0 and 14. Jugular blood samples were collected on d 0, 7, 14, and 21. In Exp. 1, vitamin E did not affect (P > 0.10) ADG, DMI, or gain:feed for d 0 to 14, 14 to 28, or 0 to 28. No effects were noted for percentage of morbidity; however, cattle receiving 1,140 IU/d had a numerically (P = 0.15) lower incidence of retreatment. During the 91-d finishing phase, a quadratic effect (P < 0.08) was noted for DMI, ADG, backfat thickness, longissimus muscle area, and yield grade. In Exp. 2, a tendency for a linear (P = 0.10) increase in ADG was observed for the first 14 d of receiving; however, ADG decreased linearly (P = 0.06) with vitamin E concentration thereafter. For the 28-d period, ADG and DMI did not differ among treatments, but gain:feed decreased linearly (P < 0.05) for d 14 to 28 and for d 0 to 28. No effects on percentage morbidity were noted in Exp. 2, and no differences were detected for ADG, gain:feed, or DMI for the 98-d finishing period. There was a linear increase in yield grade (P < 0.05) and a linear (P < 0.08) decrease in longissimus muscle area with increasing vitamin E. Heifers receiving 570 IU of vitamin E during the receiving period tended to have a higher (P < 0.09) dressing percentage at slaughter. In Exp. 3, no significant differences were detected in serum IgG titers to ovalbumin on d 0, 7 or 14; however, on d 21, a linear increase (P = 0.07) in serum IgG titers was noted with supplemental vitamin E. Supplemental vitamin E had limited effects on performance; however, effects on humoral immune response and recovery from respiratory disease warrant further research.

Age Factors↗
PubMed1987

Transferable embryo recovery rates following different insemination schedules in superovulated beef cattle.

The objective of this study was to evaluate the transferable embryo recovery rates from superovulated donor cattle after different artificial insemination (AI) schedules. Sixty mixed-breed crossbred females were administered follicle stimulating hormone (FSH) and prostaglandin F(2)alpha (PGF(2)alpha) to induce a superovulatory response. At standing estrus, donor females were randomly allotted to one of five treatment groups for AI. Donors were inseminated with two units of high-quality or low-quality frozen semen at 12, 24, 36, or 48 h after the onset of estrus in treatment Groups I, II, III, and IV, respectively, or inseminated with two units at 12, 24, 36, and 48 h (eight units/donor) in control Group V. Donor females inseminated once at either 12 or 24 h after the onset of estrus did not differ from donors inseminated in Group V in overall fertilization and transferable embryo recovery rates. The highest fertilization rate (89.5%) and transferable embryo recovery rate (74.9%) per donor resulted when AI was performed with high-quality semen at 24 h after the onset of estrus. These findings indicate that repeated insemination of superovulated beef cattle is not necessary to attain optimal fertilization rates and production of transferable quality embryos in beef cattle.

Journal Article↗
PubMedDate not supplied

Effect of pre-slaughter handling on the behaviour and blood composition of beef cattle.

The pre-slaughter handling, behaviour and blood composition of beef cattle at slaughter was studied in a commercial slaughterhouse. The main problems identified were the routine use of driving instruments and delays caused by stoppages in the slaughter line. The plasma concentration of cortisol at the time of slaughter was positively correlated with the time spent standing still and with the time spent in the pre-stun pen. The plasma activity of creatine kinase was positively correlated with the time spent in the race, but no correlations between creatine kinase and physical activity in the race were found. The plasma concentration of glucose was positively correlated with the time spent trotting and the number of times that struggling occurred. The proportions of cattle struggling, vocalizing and defaecating were greatest when they were confined in the race and pre-stun pen. Cattle kept overnight in the lairage had a greater concentration of free fatty acids at the time of slaughter than those slaughtered on the day of arrival. There were no other significant differences in either the blood composition or the handling and behaviour of cattle kept overnight in the lairage, compared with those slaughtered on the day of arrival. Some of the handling problems observed were caused by incorrect design of the handling facilities. There should be some means of removing cattle from a race if delays are encountered and some means of handling the cattle in the race other than by using an electrical goad. The optimal dimensions of races and passageways to prevent crowding and turning around should be assessed at the design stage. Non-slip floors are essential.

Abattoirs↗
PubMedDate not supplied

Weed seed viability in composted beef cattle feedlot manure.

Manure composting has gained increased acceptance by the beef cattle (Bos taurus) feedlot industry in southern Alberta, Canada. Unlike fresh manure, compost is often promoted as being "weed-free." Studies were conducted with five weed species in 1997 and thirteen in 1999 to examine the effect of feedlot manure composting on weed seed viability. Weed seeds were buried in open-air compost windrows and recovered at various times during the thermophilic phase of composting. Windrow temperature and water contents were also measured. Germinability was zero for all composted weed seeds at all sampling times in 1997. However, some seeds remained viable (positive tetrazolium test denoting respiration) on Day 70. In 1999, only one of the thirteen species retained germinability on Day 21 and only two species had respiring seeds on Day 42. Time-viability relationships during composting were defined by exponential decay models. Lethal temperatures to eliminate viability was species-dependent. In 1999, four weed species were killed in the initial 7 d of composting at a lethal temperature of 39 degrees C while temperatures of > 60 degrees C were required for two species. Regression analysis on weed seed viability versus windrow temperature resulted in significant R2 values, which showed that only 17 to 29% of the variation in viability was accounted for by temperature. The lack of definitive relationships between temperature and weed seed viability demonstrated that factors other than temperature may play a role in eliminating weed seeds during composting.

Animals↗
PubMed1991

Problems and possibilities into the next decade involving beef cattle breeding research in the southern region: purebred field data banks.

Beef cattle field records can provide data to generate important research information. The challenge in using field data for animal breeding studies involves proper editing to remove erroneous records and formulating proper models to account for fixed effects and to estimate or predict effects of interest free of bias and(or) with minimum estimation error. Use of field data for testing hypotheses is limited due to the lack of control and knowledge of the conditions under which the data were collected. Therefore, designed studies and field data should be used together to answer important questions. Some of the possible projects that can use field records are the estimation of genetic and environmental relationships among economically important traits, defining environments over which genotype x environment interactions and heterogenous heritabilities are most likely to occur, and pinpointing important fixed effects that must be accounted or adjusted for in genetic prediction models. The goal of research involving field data has been and will continue to be to provide information to improve genetic prediction models and procedures and to provide producers with genetic values with which to make informed selection decisions with a high degree of confidence.

Animals↗
PubMed1991

An overview of beef cattle improvement programs in the United States.

A periodic review of beef improvement programs is useful as a benchmark and as an opportunity to reevaluate industry direction. The history of improvement programs is reviewed with particular emphasis on recording organizations, program financing, and technological progress. The various breed associations have become the primary suppliers of performance programs, which are largely funded through registration income. Current practices are described from the aspects of traits recorded and delivery systems to collect, analyze, and distribute the data. The unique or innovative features of several breed made of the organization, technical, and educational challenges facing beef improvement. Although increased participation in genetic improvement programs is expected, substantial efforts are needed to serve adequately the needs of a changing beef cattle industry.

Animals↗