Comparison of F1 Bos indicus x Hereford cows in central Texas: I. Reproductive, maternal, and size traits.

Cows (n = 116) sired by Angus, Gray Brahman, Gir, Indu-Brazil, Nellore, and Red Brahman bulls and from Hereford dams were evaluated (when bred to the same breed of bull) for reproductive performance and cow weight and height and their calves (n = 1,161) were evaluated for birth and weaning weight in central Texas (temperate winters and subtropical summers). Cows were born from 1982 to 1985 and their calves were born from 1985 to 1999. Crossbred cows sired by Angus had a higher (P < 0.10) occurrence of calving difficulty than Gir, Indu-Brazil, Nellore, and Red Brahman crossbreds. Calves from Gir crossbreds had lighter (P < 0.10) birth weight (34.8 kg) than calves from Angus and Red Brahman crossbreds (39.4 and 37.2 kg). Calves from Angus crossbreds cows had lighter (P < 0.001) weaning weight (227.0 kg) than calves from Bos indicus crossbreds. Cows sired by Angus were lighter (P < 0.10) as mature cows (520.69 kg) than Gray Brahman, Indu-Brazil, and Red Brahman crossbreds (585.6, 571.9, and 577.6 kg, respectively). They also had smaller (P < 0.05) hip height (124.7 cm) than Bos indicus crossbreds. Mature cows sired by Indu-Brazil had greater (P < 0.05) hip height (138.3 cm) than Gir crossbreds (133.8 cm). Differences among sire breeds were noted within cow age categories (2 through 14 yr of age) for pregnancy rate, calf crop born, calf survival rate (as a trait of cow), and calf crop weaned. Angus and Indu-Brazil crossbred cows were lower (P < or = 0.10) than Gir and Nellore crossbreds for pregnancy rate, calf crop born, and(or) calf crop weaned at some, but not all, ages. Indu-Brazil crossbreds had a lower (P < or = 0.10) calf survival rate than most other breed groups at ages 11 to 14 yr. The results of this study indicate that Nellore and Gir crossbreds, but not Indu-Brazil, could perform as well or better than breeds traditionally used in cross-breeding programs of U.S. cow-calf production.

Comparison of F1 Bos indicus x Hereford cows in central Texas: II. Udder, mouth, longevity, and lifetime productivity.

Postpartum udder characteristics, aged mouth condition scores, and cow survival, longevity, and productivity were evaluated for 15 yr on F1 cows in central Texas (temperate winters and subtropical summers). The cows (n = 116) were progeny of Angus, Gray Brahman, Gir, Indu-Brazil, Nellore, and Red Brahman sires and Hereford dams. Crossbred cows sired by Nellore had smaller (P < 0.05) postpartum teat length than cows of all other crossbred groups and smaller (P < 0.10) postpartum teat diameter than Indu-Brazil and Red Brahman crossbreds. The Nellore crossbred cows had larger (P < 0.10) postpartum udder support scores (more well-supported udders) than Gir, Indu-Brazil, and Red Brahman crossbreds. As 14-yr-old cows, Angus crossbreds had lower (P < 0.05) mouth scores (indicative of one or more missing incisors) than Bos indicus crossbreds. Under actual and artificial (records were removed) culling procedures, Nellore crossbreds had the highest cow survival to age 14 and the highest longevity. Indu-Brazil crossbreds tended to be the lowest for both survival and longevity. Curves were fitted by nonlinear regression procedures to the adjusted frequencies of cows remaining at each age; scale and shape parameters were estimated and compared for the different breed groups. Breed group cow survival rates, calf crop weaned, and calf weaning weights were used 1) to construct population projection and production matrices for each breed group and 2) to generate breed group vectors containing projected age distributions and production information. Cows sired by Nellore and Gir were projected to require the fewest purebred cows to generate replacement heifers and to have the most calves and the largest total calf weight sold per year.

Injury among cavers: results of a preliminary national survey.

BACKGROUND: To estimate the frequency of and risk factors for caving-associated injuries. METHODS: A standardized questionnaire covering demographics, caving exposure, and injury history was distributed to all members of the National Speleological Society by inclusion in the monthly newsletter. RESULTS: Of 9,532 members sent a questionnaire, 301 responded (3.2%). Respondents had an average of 18 years of caving experience, and 37% had sustained one or more injuries while caving. Hypothermia was the most frequent injury, followed by fractures, animal bites, and concussions. The rate of injury was about 1 per 1,990 hours in a cave. Injury rates for females were about twice those of males; older persons and those with more than 5 years of caving experience seemed to have lower injury rates. CONCLUSIONS: Many caving injuries appear potentially preventable. Proper technique for safe climbing should be a part of exploration training. There is a need for proper belaying or rappelling for even short ascents or descents. Helmet use should be stressed, as should adequate protection from hypothermia.

Evaluation of F1 calves sired by Brahman, Boran, and Tuli bulls for birth, growth, size, and carcass characteristics.

Birth (n = 308), weaning (n = 291), feedlot and carcass (n = 142), and yearling heifer traits (n = 139) were evaluated in F1 calves sired by Brahman (BR), Boran (BO), and Tuli (TU) bulls and born to multiparous Hereford and Angus cows. Calves sired by BR were heaviest (P < .05) at birth and largest (P < .05) for cannon bone length. Tuli crosses were smaller (P < .05) for birth weight and cannon bone length than BR and BO crosses. No significant differences were observed for gestation length among sire breeds. Brahman crosses had larger (P < .05) weaning weight, hip height, and preweaning ADG than calves sired by BO and TU. Similar trends were observed for feedlot traits. Carcasses of BR crosses were heavier (P < .05) and had less (P < .05) internal fat than those of BO and TU crosses. Tuli crosses averaged greater (P < .05) skeletal maturity than BO crosses. Tuli crosses averaged greater marbling (P < .05) than BR crosses and less (P < .05) Warner-Bratzler shear force than BO crosses. No differences were observed in longissimus muscle area, fat thickness, or yield grade among sire breeds. Heifers sired by BR were heaviest (P < .05) and tallest (P < .05) at yearling measurement. Brahman F1 heifers had larger (P < .05) pelvic height and pelvic area, due to larger skeletal frame size, than BO and TU F1 heifers. These results indicate large differences in growth and skeletal size exist among calves sired by these three breeds. Several important differences also exist for carcass quality traits, but not for carcass yield traits, among these three breeds.

Dose-response relationship of isoflurane and halothane versus coronary perfusion pressures. Effects on flow redistribution in a collateralized chronic swine model.

The authors studied the redistribution of myocardial blood flow in a collateral-dependent (CD) zone as a function of coronary perfusion pressure (CPP) during isoflurane and halothane anesthesia. A swine model with CD myocardium distal to a chronically occluded left anterior descending coronary artery was developed and studied. Sixteen piglets were allowed to grow for 8-10 weeks after banding of the left anterior descending coronary artery. They were randomly anesthetized with either isoflurane (n = 8) or halothane (n = 8) as the sole anesthetic, which was used to regulate specific CPP. The resultant regional myocardial blood flows were measured using radiolabeled microspheres. Four randomly allocated CPPs, of 30, 40, 45, and 55 mmHg, were studied in each animal. Four additional collateralized animals were anesthetized with alpha-chloralose, and the same CPPs were obtained using an intravenous adenosine infusion (1-5 microM kg-1) to validate this model. There was a proportional decrease in heart rate and blood pressure in both the isoflurane and and the halothane group with CPP. Cardiac output was significantly decreased in the halothane group at 30 mmHg when compared to 55-mmHg CPP, but it was maintained in the isoflurane group. Systemic vascular resistance was significantly lower in the isoflurane group at 30 and 40 mmHg when compared to 55-mmHg CPP. Both the isoflurane and the halothane group showed a proportional and significant decrease in endo-, mid-, and epicardial blood flows at 30-mmHg CPP when compared to baseline. In both CD and normal perfusion zones, isoflurane consistently sustained a higher endocardial blood flow than halothane (5.7-41.1%).(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of dexamethasone, progesterone, gonadotropin-releasing hormone, and testosterone on estrous behavior of estradiol-treated ovariectomized heifers.

In Experiment 1, 12 ovariectomized heifers were assigned to receive weekly hormone treatments in a replicated 6 x 6 Latin square design. Hormonal treatments were given as two simultaneous injections i.m. and consisted of: 1) 2 ml propylene glycol and 2 ml propylene glycol; 2) .5 mg estradiol benzoate and 2 ml propylene glycol; 3) .5 mg estradiol benzoate and 4 mg dexamethasone; 4) .5 mg estradiol benzoate and 10 mg progesterone; 5) .5 mg estradiol benzoate and .4 mg GnRH; and 6) .5 mg estradiol benzoate and 12.5 mg testosterone propionate. The .5 mg estradiol benzoate and 4 mg dexamethasone treatment reduced the percentage of heifers in estrus compared with the .5 mg estradiol benzoate and 2 ml propylene glycol treatment. In Experiment 2, 16 ovariectomized heifers were used in four replicates of a 4 x 4 Latin square design to determine if pretreatment with progesterone potentiated the actions of estradiol. Hormonal treatments i.m. consisted of: 1) 0 mg progesterone and .2 mg estradiol benzoate; 2) 50 mg progesterone and .2 mg estradiol benzoate; 3) 0 mg progesterone and .5 mg estradiol benzoate; and 4) 50 mg progesterone and .5 mg estradiol benzoate. Progesterone pretreatment, at either dosage of estradiol benzoate, did not increase the percentage of heifers in estrus. Based on these observations, we conclude that: 1) dexamethasone inhibited estrus in estradiol-treated ovariectomized heifers and 2) progesterone pretreatment did not potentiate the actions of estradiol in ovariectomized heifers.

Serum and ruminal fluid characteristics of beef cows grazing oat pastures and supplemented with or without lasalocid.

Thirty-two mature, pregnant beef cows (avg age 8 yr, body wt 550 kg) grazing oat pastures were used to determine the effects of lasalocid on serum mineral and ruminal fluid volatile fatty acid (VFA) concentrations. Cows were blocked by breed type and assigned randomly to eight, 2-ha pastures containing oat forage from December 17, 1985 to May 6, 1986. The cows were fed .25 kg of ground corn with or without 200 mg of lasalocid daily. Based upon analyses of forage mineral composition (.53, .25, .14, .3 and 2.5% of dry matter for Ca, P, Mg, Na and K, respectively), all macrominerals except Mg were in sufficient quantities to meet the requirement for lactating cows. Lasalocid supplementation did not affect serum Mg, K or Zn concentrations (P greater than .05). During the April sampling, serum Ca was higher (P less than .05) and serum Na was lower (P less than .05) in cows supplemented with lasalocid compared with controls. The molar proportion of acetate was decreased (P less than .05) in ruminal fluid of cows fed lasalocid by d 56 (February 11); the molar proportions of acetate and butyrate were decreased (P less than .05), which decreased (P less than .05) the acetate: propionate ratio by d 84 (March 11) of supplementation. This study suggests that lasalocid is effective in altering ruminal VFA and serum mineral concentrations in cows grazing small grain forages.

Performance and carcass quality of steers supplemented with zinc oxide or zinc methionine.

Forty-five Angus steers (avg initial wt 330 kg) were individually fed for 112 d to assess the value of supplemental Zn and source on performance and carcass quality. Steers had ad libitum access to a control diet (81 ppm Zn) of 33% whole corn, 33% ground milo, 15% cottonseed hulls and 13% cottonseed meal, or this control diet with 360 mg Zn/d added from either zinc methionine or zinc oxide. Steers were slaughtered on d 114, and carcass composition was determined by specific gravity. Average daily gain and feed efficiency were not affected by dietary treatments. Steers fed zinc methionine had a higher (P less than .05) USDA quality grade than those fed the control and zinc oxide diets. Marbling score was higher (P less than .05) for steers fed zinc methionine than for those fed control and zinc oxide treatments (4.4 vs 4.0 and 4.0, respectively, where 3 = slight, 4 = small, 5 = modest). Steers fed zinc methionine tended to have more (P less than .10) external fat (13 mm) than steers fed the control diet (10 mm); steers supplemented with zinc oxide had intermediate amounts of external fat (11 mm). Steers fed zinc methionine had 10.5 and 12.8% more (P less than .05) kidney, pelvic and heart (KPH) fat than steers fed control or zinc oxide diets, respectively. The effects of zinc methionine on carcass quality grade and marbling score may be due to Zn and (or) methionine. Regardless of the mechanism, the difference represents a potential economic benefit to producers.

Influence of nutrition on serum concentrations of progesterone, luteinizing hormone and estrous behavior in dairy heifers.

Thirty postpubertal Holstein heifers were used to investigate the influence of dietary intake on 1) serum concentrations of progesterone (P4) and luteinizing hormone (LH) during diestrus and 2) estrous behavior. Heifers were randomly allotted to receive either 80, 100 or 120% of the National Research Council (NRC) requirements for energy, protein and dry matter intake for 139 d. Heifers were fed their respective diets in groups in outdoor lots for 114 d at which time individual feeding of diets was initiated in a stanchion barn. Estrus was synchronized with two injections of prostaglandin (PG) so that on d 138 of dietary treatment the heifers were in diestrus (means = d 8 of estrous cycle). Also, on d 138, blood samples were collected via jugular cannula at 20-min intervals for 12 h beginning at 0630. After collection of the 37th blood sample, all heifers were treated with PG and additional blood samples were collected at 1-h intervals for 24 h. Immediately thereafter, all heifers were moved to a common outdoor lot for 72 h of continuous observation for estrous behavior. Weight gains during the experimental period differed among groups and were 46 +/- 5, 83 +/- 5 and 113 +/- 4 kg for the heifers fed 80, 100 and 120% of the NRC requirements, respectively. Mean serum concentrations of P4 for the 80% NRC group (4.6 +/- .6 ng/ml) tended to be lower than both the 100% (5.9 +/- .6 ng/ml) and 120% (6.0 +/- .5 ng/ml) NRC groups, respectively. Mean serum concentrations of LH, number of LH secretory peaks/12 h and LH peak amplitude were similar among all NRC groups. Rate of decline in serum P4 after PG was also similar among all NRC groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Commercial feasibility of embryo transfer technology: a case study.

The owner of a 500-cow Holstein herd requested economic assessment of his embryo transfer program. Actual net economic benefit was determined from marginal cost and present value of lifetime milk predicted from first lactations of 24 cows produced by embryo transfer compared with those of their 51 contemporaries sired by artificial insemination. Actual average pregnancy rate was 60% by embryo transfer or AI. An average of 5.5 transferable embryos was obtained per collection, which produced 1.37 cows in first lactation. Additional milk from embryo transfer cows was from more intensive selection of sires. Additional milk from the donor cows did not differ from zero. Actual marginal cost of a replacement by embryo transfer was +215, but it would have been +200 with same +25/unit semen price as contemporaries. If donors had been from the elite 5% for transmitting ability in milk, present value of gain in milk (5% real interest rate) ignoring additional feed costs would have been less than the cost of embryo transfer. For management and costs similar to this case, embryo transfer is not economically justified for producers earning income primarily from the sale of milk.

Heparin kinetics during hemodialysis: variation in sensitivity, distribution volume, and dosage.

A method to assess heparin kinetics and individualize dosages was examined in 27 patients during chronic hemodialysis. Pretreatment heparin sensitivities were determined to establish the relationship between heparin concentration and activated clotting times (ACTs). Distribution volume was calculated by dividing the heparin loading dose by the 5-min heparin concentration. Assessments were made during three different dialysis periods. There was a 10-fold range in pretreatment heparin sensitivities. Intrapatient heparin sensitivity remained relatively consistent between dialysis periods. The degree of heparin sensitivity was significantly correlated to baseline ACT. Patients post-splenectomy were more sensitive to heparin. Large intra- and interpatient variation in distribution volume was also observed. Men, patients less than 60 years old, and patients post-splenectomy represented variables that contributed to higher heparin dose requirements.

Survival rates of 2,728 patients with end-stage renal disease.

This multicenter regional study analyzes survival of a large group of patients who began chronic dialysis or received their first renal transplant during the 5 1/2-year period that ended in June 1983. Survival was determined from the onset of renal replacement therapy, irrespective of changes in treatment modality. Univariate life-table analysis was used to examine more than 35 risk factors. Age of patients at entry into the therapeutic program significantly affected survival. General survival rates were lower for patients with diabetes than for nondiabetics, irrespective of treatment modality, with the exception of those older than 60 years of age. Five-year graft survival was lower for diabetics than for nondiabetics in all age groups, irrespective of source. Patients with systemic lupus erythematosus, focal glomerulosclerosis, or glomerulonephritis had the highest survival rates, whereas those with primary renal malignant lesions, primary hypertensive disease, or diabetes mellitus as the cause of renal failure had the lowest. Concurrent morbid conditions that adversely affected survival included arteriosclerotic heart disease, peripheral vascular disease, noncutaneous malignant lesions, chronic pulmonary disease, and multiple coexisting morbid conditions. Although the objective of this study was to analyze survival for single patient characteristics, irrespective of treatment modality, analyses of survival rates by treatment modality for a control group indicated that minimal differences were evident by the third year among the four treatment groups: in-center hemodialysis, home hemodialysis, living related donor transplantation, and cadaver transplantation; however, recipients of cadaver grafts had lower survival rates than all other groups, even those maintained by in-center hemodialysis (P = 0.025).(ABSTRACT TRUNCATED AT 250 WORDS)

Use of sugar and povidone-iodine to enhance wound healing: five year's experience.

Over a 56-month period (January 1976 to August 1980), we treated 605 patients for wounds, burns, and ulcers with granulated sugar and povidone-iodine. Rapid healing ensued, due to a reduction in bacterial contamination, rapid debridement of eschar, probable nourishment of surface cells, filling of defects with granulation tissue, and covering of granulation tissue with epithelium. The requirements for skin grafting and antibiotics were greatly reduced, as were hospital costs for wound, burn, and ulcer care.