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At least 253 records · Page 14Linked to original sources
PubMed2002

Genetic variation in fatness and fatty acid composition of crossbred cattle.

Mature Hereford cows (766) were mated to 97 sires from seven breeds (Jersey, Wagyu, Angus, Hereford, South Devon, Limousin, and Belgian Blue), resulting in 1,215 calves born over 4 yr (1994 to 1997). These cattle comprised Australia's 'Southern Crossbreeding Project." Heifers were slaughtered at an average of 16 mo with hot standard carcass weight of 219 kg and 9 mm fat over the rump. Steers were slaughtered at an average of 23 mo with carcass weight of 319 kg and 13 mm fat over the rump. Meat and fat samples were taken from the carcass on the day after slaughter for subsequent laboratory analysis of i.m. fat content and fatty acid composition. Data were analyzed using uni- and bivariate animal models containing fixed effects of cohort, management group, birth month, and sire breed. March-born calves had fat with a 0.5 degrees C lower melting point, 0.6% higher total monounsaturated fatty acids, and 0.7% higher fatty acid desaturation index than calves born in April. Steers born in 1997 were the only cohort finished on pasture, and they had much more yellow fat than the other cohorts. Four heavy breed crosses (Angus, South Devon, Limousin, and Belgian Blue) averaged 284 kg carcass weight, followed by purebred Hereford (268 kg), Wagyu (244 kg) and Jersey (236 kg). Angus had the greatest fat depth (14.3 mm), ahead of Hereford and Wagyu (11.9 mm), Jersey (10.7 mm), South Devon and Limousin (9.9 mm) and Belgian Blue (8.0 mm). Jersey, Wagyu, and Angus had themost i.m. fat (4.6%), followed by Hereford and South Devon (3.8%), and Limousin and Belgian Blue (3.1%). The highly marbled Jersey and Wagyu had softer fat (6% lower fat melting point) than the other breeds. Angus were more highly marbled, similar to Jersey and Wagyu, but had harder fat similar to the leaner breeds. Heritabilities for all traits were low to moderate (16 to 36%). Genetic correlations between fatty add composition and carcass traits were not significant, indicating little evidence of antagonisms between traits that would prevent genetic progress in both production and quality.

Adipose Tissue↗
PubMed1998

Rapid spread of a unique strain of Pasteurella haemolytica serotype 1 among transported calves.

OBJECTIVE: To determine the rate and mode of infectious spread of Pasteurella haemolytica among calves maintained under typical conditions during collection, transport, and the first month of feeding. ANIMALS: 101 two- to five-month-old Angus-crossbred calves. PROCEDURE: Samples obtained from cattle prior to and after they were transported to a feedlot were used for isolation and characterization of P haemolytica. Samples were also obtained from additional calves, some of which were sick, and these calves were then commingled with the transported calves for 3 days. A strain of P haemolytica that contains a rare deletion of the 4.2-kilobase streptomycin- and sulfonamide-resistance plasmid was inoculated into both palatine tonsils of 12 calves. Nasal secretions were aspirated from the ventral nasal meatus. Tonsillar wash specimens were procured. Pasteurella haemolytica organisms were quantitatively cultured and identified on the basis of colony morphology and response to specific antisera. Plasmids were isolated by an alkaline lysis procedure and identified by agarose gel electrophoresis. RESULTS: A single plasmid profile was observed from P haemolytica isolated from samples obtained prior to shipment. Commingled calves were shedding P haemolytica containing each known plasmid profile. After shipment, samples contained P haemolytica isolates with each known plasmid profile. The plasmid profile of the unique P haemolytica isolate was recovered from all 12 inoculated calves and 10 other calves. Some calves simultaneously shed P haemolytica isolates with differing plasmid profiles. CONCLUSIONS AND CLINICAL RELEVANCE: Pasteurella haemolytica serotype 1 was horizontally transmitted among calves within days of commingling, which continued after calves were transported to a feedlot.

Animals↗
PubMed1997

Assessing the efficiency of multiplicative mixed model equations to account for heterogeneous variance across herds in carcass scan traits from beef cattle.

Data (n = 2,658) from live animal ultrasonic measures from 17 Angus herds were used to evaluate a multiplicative mixed model that incorporates scaling factors to correct for across-herd heterogeneity of variance. Traits included were ribeye muscle area (EMA), surface fat at the P8 site (P8), surface fat between the 12th and 13th ribs (RIB12), and weight at scanning (WEIGHT). Cattle ranged in age from 501 to 698 d and represented 291 contemporary groups. Data were initially analyzed using single-trait, animal model, Method R procedures to estimate variance components and heritabilities (h2). These estimates were incorporated into a multiplicative mixed model that simultaneously estimates breeding values (EBV) and heterogeneity factors. Re-estimation of h2 after scaling the data with the correction factors was explored to obtain a measure of the improvement in the genetic evaluation and to detect changes in ranking of individuals and herds. Initial h2 estimates for EMA, P8, RIB12, and WEIGHT were .36, .39, .29, and .48, respectively. Scaling factors ranged from .25 for P8 in a herd with eight records to 1.96 for RIB12 in a herd with 86 individuals. Re-estimates of h2 increased by an average of 4.2% for all the traits as a result of correcting for heterogeneity. Deviations of new scaling factors were within expectations. Correlations between EBV with and without heterogeneity correction were greater than .97 for all the traits. However, some substantial re-rankings of herds were observed for some traits in the smaller herds.

Analysis of Variance↗
PubMed1974

Endocrine gland and brain weights of market weight bulls and steers representing the shorthorn breed and several breed crosses.

Thyroid, adrenal, pituitary and brain weights were first determined in 1971 in 492 market weight cattle representing purebred Shorthorns and crosses of "foreign" breeds, Charolais, Simmental and Limousin with Hereford, Angus and Shorthorn. Thyroid weights were also determined in a similar group of 433 cattle the following year. The data were reported on a per 100 kg body weight basis and analyzed within the subgroups of breed of sire, breed of dam and location. The average thyroid weight per 100 kg of body weight for males within subgroups over the two years ranged from 3.99 to 8.71 g, while that for steers ranged from 3.81 to 4.41 g. The average thyroid weight for a group of 18 Limousin sired heifers was 3.71 g. The average adrenal weight per 100 kg of slaughter weight ranged from 3.66 to 4.20 g in the males and from 3.66 to 3.86 g in the steers. Pituitary weight per 100 kg body weight at slaughter ranged from 486-511 mg in bulls and from 469-510 mg in steers. Average brain weight ranged from 85.5 to 97.3 g in males and from 92.2 to 94.1 g in steers.Breed differences existed only for the pituitary gland, with Simmental sired males and steers having heavier glands than Charolais sired males and steers. Sex differences were significant for the thyroid and the brain. Thyroids of males were generally heavier than those of steers, while brains of steers were heavier than those from males.Thyroid, adrenal and brain weights were significantly different between two genetically similar purebred herds of Shorthorns.

Adrenal Glands↗
PubMed1981

Growth and muscle development of feedlot cattle of different genetic backgrounds.

The effects of crossbreeding, cattle type and dietary energy level on semitendinosus muscle (ST) development, feedlot performance, daily carcass protein and fat gain and serum anabolic hormone concentrations were studied. Over 3 consecutive years, 176 feedlot steers representing four cattle types - unselected Hereford (UH), selected Hereford (SH), Angus x Hereford x Charolais (AHC) and Angus x Hereford x Holstein (AHH) - were fed either an all-corn silage (HS) or a high grain (HG) diet. Steers were slaughtered on day 1 and at the end of the feedlot trial, and ST muscles were removed rapidly. During years 2 and 3, single blood samples were obtained from steers on days 1, 29, 57, 113 and 169, and analyzed for insulin and growth hormone (GH). Steers fed HG had a higher (P less than .005) average daily gain (ADG) than steers fed HS, and cattle type had an effect (P less than .005) on ADG. Cattle type and HG affected (P less than .005) daily carcass protein and fat gain. Weight of ST muscle and total muscle RNA, DNA and protein content increased with frame size, and HS steers had heavier (P less than .05) ST muscles than the HG steers. Steers fed HG had higher (P less than .01) serum insulin concentrations than steers fed HS, but there were no consistent cattle type effects. Serum GH concentrations were not affected by cattle type or diet. Serum insulin concentrations, combined across diet and cattle types, were correlated (P less than .01) with ADG; however, serum GH, assessed on the same basis, was not related to ADG. Average daily protein and fat gain were positively related to serum insulin and were negatively related to serum GH.

Animals↗
PubMed1982

Induction of twins in different breeds of cattle.

Two experiments were conducted examining bilateral transfer of Hereford X Angus crossbred embryos to Angus, Hereford and Hereford x Angus crossbred recipients. In Exp. 1, both virgin heifers and parous cows were used as recipients, in Exp. 2, only virgin heifers were used. No differences in production of twins due to breed of recipient was observed. In Exp. 1, heifers had as high a twinning rate and proportion of pregnancies carried to term as cows. About 9% of the heifers in Exp. 2 experienced late gestation abortion (based on recipients pregnant at 42 d), a problem which was not observed among heifers in Exp. 1. No association between body weight at transfer and abortion was observed. Twin pregnancy was associated with a higher incidence of retained placentas (Exp. 1, P less than .05; Exp. 2, P less than .10), lower birth weight/calf (P less than .01 in both experiments) and shorter gestation period (P less than .01 in both experiments). Calf mortality at birth was similar among twins and singles and, in Exp. 2, a lower (P less than .02) incidence of dystocia was observed among heifers giving birth to twins than among those with single calves. The results of these experiments indicate that both beef heifers and beef cows of three common breed types are capable of maintaining twin pregnancies and successfully producing twins.

Abortion, Veterinary↗
PubMed1991

An outbreak of Vicia villosa (hairy vetch) poisoning in grazing Aberdeen Angus bulls in Argentina.

Vicia villosa (hairy vetch) is used as a forage source in some cattle-producing areas in Argentina. The plant had no previous reports of toxicity in this country. A herd of 33 Aberdeen Angus bulls grazed during 20 days in October on a pasture composed mainly of hairy vetch. Eight animals developed conjunctivitis, rinitis, dermatitis, loss of hair and fever. All of them died within 15 d after the development of signs with a marked loss of body condition. No more animals became sick 5 d after the removal of the herd from the pasture. Serum parameters tested (calcium, phosphorus, magnesium, GOT, alfa-GT and bilirubin) enlarged liver and spleen, generalized hemorrhage in the abomasum, dilated kidneys and multiple pale areas on the heart. Severe necrotizing granulomatous myocarditis, interstitial nephritis, and necrotizing cholangitis were the most striking microscopic changes. Close observation of animals feeding on pastures in which V villosa is dominant is the only prevention.

Animals↗
PubMed2004

Effect of management strategies on reducing heat stress of feedlot cattle: feed and water intake.

Three experiments were conducted to evaluate management strategies designed to decrease heat stress of cattle finished during the summer. In Exp. 1, 144 Angus crossbred yearling steers were assigned to three treatments: 1) ad libitum access to feed at 0800 (ADLIB); 2) fed at 1600 with feed amount adjusted so that no feed was available at 0800 (BKMGT); and 3) fed at 1600 at 85% of predicted ad libitum levels (LIMFD). Treatments were imposed for 23 d of an 82-d study, after which all steers were fed ad libitum at 0800. Treatment did not affect (P > 0.10) overall DMI, although ADLIB cattle tended to consume less feed. Overall water intake was decreased (P < 0.05) by 6.8 L x animal(-1) x d(-1) for LIMFD vs. ADLIB steers. In Exp. 2, 96 Angus crossbred yearling steers were assigned to three treatments: 1) control, no water application; 2) water applied to the pen surfaces between 1000 and 1200 (AM); and 3) water applied to pen surfaces between 1400 and 1600 (PM). Water intake and DMI did not differ among treatments; however, feed efficiency of AM steers was superior (P = 0.06) to that of PM steers. Conversely, marbling scores of PM steers were higher (P = 0.06) than those of AM steers. In Exp. 3, 192 crossbred steers were used to determine the effects of feeding time (0800 [AMF] vs. 1400 [PMF]), with (WET) and without (DRY) sprinkling (20 min every 1.5 h between 1000 and 1750). Feed DMI did not differ among treatments; however, water intake and marbling scores were highest (P < 0.05) for AMF/DRY steers. During these experiments, bunk scores (0 = <10% of feed delivered remaining; 1 = 10 to 50% of feed remaining; 2 = >50% of feed remaining) were assigned to each pen at various times during the day. In Exp. 1, bunk scores of BKMGT pens remained similar (P > 0.20) under varying environmental conditions, whereas LIMFD steers had lower scores (P < 0.05) as days on feed increased, even under hot environmental conditions. In Exp. 3, bunk scores of PMF/WET steers tended to be lower (P < 0.10) at 1700 and 2000 compared with PMF/ DRY pens under mild heat stress but not under severe heat stress. Alternative feeding regimens and sprinkling can alter the feed intake pattern of steers. Heat stress management strategies imposed in these experiments had minimal effects on cattle performance. Such strategies would be most useful for decreasing the susceptibility of cattle to hyperthermia and reducing related feedlot cattle deaths without adversely affecting performance.

Animal Feed↗
PubMed1992

Effects of antibiotic prophylaxis on postoperative complications after rumenotomy in cattle.

A single preoperative dose of antibiotic proved as effective as a preoperative and 7-day postoperative course in reducing complications following rumenotomy in cattle. Exploratory rumenotomy was performed on 29 healthy Angus steers, which were allotted to the following treatment groups: (1) no antibiotic therapy, (2) single-dose, preoperative, antibiotic prophylaxis, using potassium penicillin G, and (3) preoperative potassium penicillin G prophylaxis, followed by a 7-day postoperative course of procaine penicillin G. Steers receiving antibiotics had significantly greater postoperative feed intake, lower rectal temperatures, and fewer abscesses at the surgical site than those receiving no antibiotics. There was no significant difference between animals receiving a single preoperative dose of antibiotic and those treated for an additional 7 days after surgery. In human medicine, it is generally agreed that a single preoperative dose of antibiotic offers effective prophylaxis. There are few published reports on antimicrobial prophylaxis in the veterinary literature, particularly in regard to large animals. Considering USDA requirements for milk withholding times and withdrawal times prior to slaughter for food animals receiving antibiotics, the findings of this study have medical as well as economic value.

Abscess↗
PubMed2006

Choice of attractive conditions by beef cattle in a Y-maze just after release from restraint.

To provide useful information on how to moderate posthandling stress, the attractiveness of different conditions to beef cattle just after release from restraint was determined. Angus heifers were individually allowed to enter a choice area after 2 min of restraint in a squeeze chute and to choose between 2 pens. After the heifer had chosen a pen, it could freely access both test pens and the choice area for a further 5 min. In Exp. 1, each heifer was given 1 of the following choices: a pen with 3 familiar heifers (PEERS) vs. a pen with a pile of hay on a metal rack (FOOD; n = 34); PEERS vs. the bare pen (BARE; n = 34); and FOOD vs. BARE (n = 35). When the choice combination was PEERS vs. BARE, more heifers chose PEERS (P < 0.05). When the choice combination was PEERS vs. FOOD, more heifers than expected tended to choose PEERS (P < 0.10), whereas FOOD and BARE did not differ. The latency to choose either pen was shorter if PEERS was 1 of the 2 choices (P < 0.01). After choosing, more heifers entered the PEERS pen than the FOOD (P < 0.05) or BARE (P < 0.01) pens. In Exp. 2, another 86 heifers were given 1 of the following choices: a pen with a familiar handler standing inside (STI) vs. a pen with a novel object (NO; n = 29); a pen with the handler standing outside the pen (STO) vs. NO (n = 29); a pen in which the handler was sitting inside (SI) vs. NO (n = 28). Fewer heifers chose the pen with the human (STI, STO, and SI; all P < 0.01). Except for the choice of STO vs. NO, the number of heifers that had voluntarily chosen either pen was larger than expected (STI and SI; both P < 0.01). The number of times in which the NO pen was entered was greater than the STI and STO (P < 0.01), although the number of times in which the SI and NO pens were entered was not different. More heifers avoided the human, particularly a standing human. In conclusion, just after handling with restraint, returning cattle to the group of peers and not approaching the cattle needlessly should moderate their stress.

Animal Feed↗
PubMed1990

Supplementation of dormant tallgrass-prairie forage: II. Performance and forage utilization characteristics in grazing beef cattle receiving supplements of different protein concentrations.

Two experiments were conducted to evaluate the influence of supplemental protein concentration on the intake and utilization of dormant range forage by beef cattle. In Exp. 1,97 pregnant Hereford x Angus cows (avg wt = 454 kg) were assigned randomly to three isocaloric treatment supplements: 1) low protein (LP), 13% CP; 2) moderate protein (MP), 25% CP; and 3) high protein (HP), 39% CP. In Exp. 2, 15 ruminally and 12 esophageally cannulated steers (avg wt = 319 and 355 kg, respectively) were assigned randomly to LP, MP and HP treatments and were used in a 22-d winter grazing trial to evaluate forage intake and utilization characteristics. In Exp. 1, cow body condition (BC) and BW changes responded in linear (P less than .01) and quadratic (P less than .01) fashions to increasing protein concentration, with MP and HP displaying the least BC and BW loss from trial initiation (d 1) through d 84. From d 84 to calving (avg calving date = d 120), only the HP supplement continued to be effective in minimizing BC loss (P less than .01). Calf birth weight tended (P = .17) to increase in a linear fashion to increasing supplemental protein concentration, but calf ADG and cow reproductive efficiency were unaffected (P greater than .10). In Exp. 2, forage OM intake responded in a quadratic fashion (P less than .10), with the MP treatment having the highest NDF digestibility and ruminal OM fill. In conclusion, beef cow BC and BW losses during the winter grazing period were minimized with increasing supplemental CP concentration. Intake and utilization of dormant forage by steers were improved with moderate (26%) levels of CP in the supplement.

Animal Feed↗
PubMed2000

Forage systems for production of stocker steers in the upper south.

The southern states produce large numbers of beef calves that are generally weaned and sold in autumn. Keeping calves in this region beyond weaning to graze high-quality forages through a stocker cattle phase could improve profitability. Autumn-weaned Angus crossbred steers were allocated by breeding and weight to four forage systems that began in mid-November and continued through mid-October as follows: System 1, tall fescue (Festuca arundinacea Schreb.) and Kentucky bluegrass (Poa pratensis L.)-white clover (Trifolium repens L.); System 2, tall fescue, caucasian bluestem (Bothriochloa caucasica [Trin.] C. E. Hubbard) and tall fescue-red clover (Trifolium pratense L.); System 3, orchardgrass-alfalfa and bluegrass-white clover; and System 4, rye (Secale cereale L.), soybeans (Glycine max)-foxtail millet (Setaria italica), and bluegrass-white clover. All steers were supplemented with hay or silage previously cut from their respective systems when forage for grazing was limited. System 2 which used stockpiled tall fescue for winter grazing and caucasian bluestem for summer forage plus fescuered clover for hay and grazing in a three-paddock system, resulted in greater (P < .01) gain per hectare and per steer, more grazing days, and reduced stored forage requirements and produced more surplus feed than the other systems tested. Gains per hectare for Systems 1 through 4 were 454, 554, 472, and 487 kg (SE = 18), respectively. Harvested forage from Systems 1, 2, and 3 met needs for stored forages but System 4 required additional "purchased" hay. Stored forage was fed for 61, 38, 112, or 104 d for Systems 1 through 4, respectively. Within the physio-climatic region of this experiment, a simple three-paddock system based on cool- and warm-season perennial forages could improve beef production per unit of land area while reducing inputs of labor and equipment.

Animal Feed↗