Evaluations of genotypexenvironment interactions of beef bulls performance-tested in feedlot or pasture.

Purebred Angus (n = 96) and Polled Hereford (n = 96) bull calves sired by bulls of either low or high yearling weight performance lines were assigned to either creep-fed or non-creep-fed treatment before weaning for four calf crops. For each breed, after weaning in the fall, half of the calves within each of the four groups were fed a high concentrate diet for 189 d after weaning in a feedlot and the remainder were put on winter temporary pastures (rye or ryegrass) followed by summer grazing on pearl millet and bermudagrass pastures for 329 d after weaning. Dependent variables were ADG for various intervals and the complete test period, weight, height and scrotal circumference at periodic intervals, and weight per day of age at regular intervals during the test. The model included breed, performance line, sire nested within breed and line, year, age of dam, preweaning treatment, postweaning treatment, and two- and three-factor interactions. Age of calf was included as a covariate for weight, height, and scrotal circumference measurements. Line and breed differences generally were significant for weight but not for height. The interaction of primary interest (line by preweaning treatment by postweaning treatment) was not significant. The high growth performance line gained faster than low growth performance line for all intervals and were 45 kg heavier by 189 d after weaning. Preweaning treatment did not affect postweaning ADG but did affect weight per day of age. Creep-fed calves were heavier than non-creep-fed calves and maintained this advantage during the postweaning treatment periods in both the feedlot and pasture. Both preweaning treatment groups had similar ADG after weaning. Angus were 23 kg heavier at weaning than Polled Herefords; however, breed weight means were similar by 16 mo of age. In summary, bulls from different selection lines for growth were identified in feedlot and pasture when adjustments were made for prior management effects. The lack of significant interactions in these data indicates that central test station data, appropriately adjusted, are useful for ranking bulls on genetic merit for growth in feedlot and on pasture.

Subsequent reproduction and calf performance of nonpregnant cows compared with pregnant cows and replacement females.

This study was conducted with Angus, Polled Hereford and Santa Gertrudis straightbred and crossbred cows. The subsequent cow breeding and calf performance of cows that were nonpregnant (NP) were compared with cows that were pregnant (PG) at the time calves were weaned. All NP cows had a calf the year previous to their being nonpregnant. They were diagnosed as physically sound with no detection (by rectal palpation) of an abnormal reproductive tract. The NP and PG cows were aged 4 to 9 yr. Also, the NP cows were compared with replacement females exposed to calve first as 2- and 3-yr-olds (H2 and H3, respectively), and with cows exposed for second calving as 3-yr-olds (C2). Cows were assigned within breed composition and age to sire breeding groups on pasture. Subsequent calving and weaning rates were similar for NP, PG and H2 cows, similar for H3 and H2 cows and lowest (P less than .05) for C2 cows. Calves from NP and H3 cows were born earlier (P less than .05) in the calving period than calves from PG and H2 cows, whereas calves from C2 cows were born later (P less than .05) than those from NP, PG and H3 cows. Calving difficulty was similar for NP, PG and C2 and greatest (P less than .05) for H2 cows. Calf 205-d weights were highest (P less than .05) for NP, similar for PG and H3 and lowest (P less than .05) for C2 and H2 cows. Calf weaning weight per cow exposed for breeding from NP cows was 13.8, 32.3, 55.2 and 1.0 kg higher than from PG, H2, C2 and H3 cows, respectively. Causes for cows being nonpregnant were reported. Also, calving patterns during 6 consecutive calving periods (6 yr) were evaluated.

Clinical experience with the silicone tracheal prosthesis.

The superiority of using the patient's own tissue for tracheal reconstruction is acknowledged. When this is impossible an alternate method is mandatory. From 1970 to 1988, 62 patients with benign and malignant tracheal stenosis had airway continuity established with a silicone tube. A straight graft was used in 48 patients. Twenty-eight had strictures, two tracheoesophageal fistulas and strictures, five primary malacia, and 13 malignant tumors. In 20 with noncancerous tracheal obstruction the airway was resected and a graft interposed. Distal suture line granulomas developed in six of these patients. Two had subglottic granulomas. One had graft dehiscence after dissolution of absorbable suture material. This graft was replaced with a silicone T tube. Four patients with end-to-end anastomosis of the graft to the trachea died in 6 to 12 months. Six others were lost to follow-up. In 15 of the 48 with benign disease the stent was placed within the lumen. Six in this group died. Thirteen of the 48 patients had a malignant tumor. In six the tube was used for palliation; none are alive. Seven underwent resection; five are living 1 to 8 years after the operation, two died of their disease in 1 1/2 to 2 years, and two of the five living are undergoing irradiation for recurrent cancer. Fourteen individuals with tracheocarinal malignancy received a bifurcated graft. All six patients with a palliative intraluminal stent died. Among eight individuals, four died of disease in 1 to 4 years. Four are alive, but two have suture line granulomas and two are undergoing irradiation for residual carcinoma. Mediastinal infection, mucus encrustations of the intraluminal prosthesis, and impedence of pulmonary secretions across long tubular segments have not been manifest. These silicone tubes are well tolerated and function satisfactorily as an airway.

Breeding performance of beef bulls assigned to two-sire cow groups on pasture.

Angus, Polled Hereford and Santa Gertrudis bulls from ages 1 through 5 and 7 yr were assigned to 26 two-sire breeding groups. Each year, straightbred and crossbred cows of these breeds were allotted at random within breed composition, age of dam and calving date to breeding groups on pasture. Sires within each breeding group or pair were the same age at breeding and were two of the three breeds of sires. Neither calving rate nor the proportion of calves born by one vs the other sire in the two-sire breeding groups was affected by sire age among breeding groups. For a given breed, there was no uniformity among the sires in the proportion of calves they sired in their two-sire breeding groups. The proportion of calves born for the 26 sire pairs averaged .64 vs .36 (SE = 0.4 for either high or low value) for one vs the other sire in a sire pair with no indication that calving rate was affected by unequal proportions of calves by sires within sire pairs. Cows calved significantly earlier in the calving period (b = -.775 +/- .127) as calving rate increased among sire pairs. The number of days from the start of the breeding period to calf birth was affected by differences between sires in sire pairs for 8 of the 26 pairs, but there were no significant differences due to sire pair or breed of sire because of interaction between these two variables.

Relationship of breeding soundness evaluation score and its components with reproductive performance of beef bulls.

Angus, Polled Hereford and Santa Gertrudis bulls were subjected to a breeding soundness evaluation (BSE) just prior to being exposed to cows for 90 to 95 days in single-sire units under natural breeding conditions on pasture. Forty-eight of 55 bulls subjected to scrotal and semen evaluations passed the BSE and were considered acceptable for breeding. Of the bulls that passed BSE, 18 (six bulls from each breed) were used for breeding for each yr of the 2-yr study. Of the bulls used for breeding, breed of sire differences were significant for scrotal circumference and calving rate, while differences among sires within breed of sire were significant for secondary morphology, motility score and calving rate. The difference between means for bulls used vs bulls that failed BSE was significant for all eight traits. Correlations among various scrotal and semen evaluations were compared for bulls used vs bulls that failed BSE. Of the eight traits, only the motility score was significantly correlated with the calving rate. After the exclusion of bulls that failed to pass BSE, there remained differences (P<0.01) among bulls within breed of sire for calving rate. Thus, there is a need for an additional easy-to-use procedure that would more accurately predict the breeding performance of bulls.

Reproduction and calf performance of Angus-sired and Polled Hereford-sired cows bred to Angus and Brahman bulls for primiparous calving as two- vs three-year-olds.

This 4-yr study was conducted with Angus (A)-sired and Polled Hereford (PH)-sired crossbred heifers that were exposed to either A or medium-frame Brahman (B) bulls from primiparous calvings either as 2- or 3-yr-olds. Each year, heifers were allotted at random within breed composition and age of dam to breeding groups on pasture for an 84-d breeding period that began in late March or early April. Results indicated that differences due to age of dam (AOD), calf sire breed (CSB) and dam sire breed (DSB) were similar for calving rate, earliness of calving in the calving period and percentage of calves born alive, percentage weaned of those born alive and percentage weaned of cows exposed. The 3-yr-old cows had less calving difficulty and their calves had higher birth weight, average daily gain (ADG) to weaning, 205-d weight and 205-d weight/cow exposed than the 2-yr-old cows. Compared with the B-sired calves the A-sired calves had lower birth weight, ADG to weaning and 205-d weight; however, 205-d weight/cow exposed was similar. Compared with the PH-sired cows, the A-sired cows had less calving difficulty, and their calves had higher ADG to weaning and higher 205-d weights/cow exposed. Under conditions similar to those of this study, it would be economically advantageous to calve first at 2 yr of age rather than at 3 yr of age.

Breeding performance of bulls assigned either to 40 cows per bull or 80 cows per two bulls during the breeding period.

The reproductive performance of Angus (A), Polled Hereford (PH) and Santa Gertrudis (SG) bulls was compared when exposed to 40 cows/bull vs 80 cows/two bulls during a 90- to 95-d breeding period on pasture. Cows were A, PH and SG straightbreds and crossbreds of these breeds. Each year, cows were allotted at random within breed composition and age of dam to breeding groups. A replicate consisted of two 40-cow single-sire units with bulls of two breeds and an 80-cow two-sire unit with two bulls of the same breeds and all four bulls of the same age. There were eight replicates of PH and SG bulls and five replicates of PH and A bulls. At breeding time, 20, 16, 12 and 4 bulls were 2-, 3-, 4- and 5-yr-olds, respectively. Reproductive performance of bulls was evaluated in terms of calving rate (CR) of cows exposed to them and number of days (NOD) from the beginning of the breeding period until calf birth. The 80-cow groups calved 3.7 d earlier (P less than .05) in the calving period and had a similar CR compared with the 40-cow groups. The PH-A replicates calved 3.5 d earlier (P less than .05) and had 7.3 percentage units higher (P less than .01) CR than PH-SG replicates. Results of this study indicated that 80-cow two-sire breeding groups had an advantage over the 40-cow single-sire groups in terms of calves born earlier in the calving period, with no reduction in CR.

Cow breeding and calf growth performance as affected by pregnancy status the previous year.

A 2-yr study was conducted to compare the subsequent cow breeding and calf performance of cows that were nonpregnant with cows that were pregnant at the time calves were weaned. Cows were Angus (A), Polled Hereford (PH), Santa Gertrudis (SG) straightbreds and crossbreds of these breeds. Nonpregnant cows (G1) were 4- to 9-yr-olds that had a calf the previous year and appeared to be physically sound with no detection (by rectal palpation) of an abnormal reproductive tract due to disease, abnormal growth or calving difficulties. Pregnant cows (G2) were of similar age and breed composition to G1 cows. The 93 G1 and the 193 G2 cows were assigned within age and breed composition to sire breeding groups on pasture in an approximate 1:2 ratio, respectively, per sire. There were six A, three PH and one SG sires. The year prior to G1 cows being nonpregnant, G1 cows calved 11 d later (P less than .01) than G2 cows. Subsequent to their being nonpregnant, G1 cows gained 27 kg more (P less than .001) weight during the breeding period, had 5.4 percentage units more (P less than .29) calves born, had calves 17 d earlier (P less than .001) in the calving period, had calves that gained at a similar rate to weaning and had calves that were 14 kg heavier (P less than .01) at weaning (due to their being 17 d older) compared with G2 cows and calves.

Unified approach for nonmalignant esophageal lesions using right colon and terminal ileum. A 30-year experience.

Over the past 30 years, the authors reconstructed the esophagus with the right colon in 85 patients who had congenital and benign disease. The first individual operated upon in 1955 was asymptomatic. Nine patients had congenital tracheoesophageal fistula with atresia, four esophageal varices, 31 advanced obliterative esophagitis, and 23 corrosive destruction. In seven patients, severe esophagitis followed esophagogastrectomy, four had unsuccessful operations for achalasia, and seven had colon bypass following esophageal perforation. Eleven early nonfatal complications occurred. Remote nonfatal complications were seen in six patients. Three early deaths followed dehiscence of an intrathoracic esophago-colon anastomosis, and one patient died from peritonitis (4%). Four individuals died over the study period, and five patients were lost to follow-up. The late results in 72 patients show that 61 (84%) believe they have a satisfactory result, nine (13%) individuals are symptomatic, and two patients (4%) are classified as failures. Early complications have been minimized by employing preoperative intestinal angiograms and anastomotic stapling techniques, and by using the Doppler intraoperatively to prognosticate colon blood flow. Significant observations have been: Anastomosis in the neck is preferable; the transplanted colon dilates from loss of motor activity but is functionally adequate; an isoperistaltic segment is preferable, but antiperistaltic segments can be used; and colonic mucosa is relatively resistant to acid-peptic digestion.

Castration method and progesterone-estradiol implant effects on growth rate of suckling calves.

Eighty male calves nursing their dams and averaging 15 d of age were used to evaluate a method of nonsurgical castration and a growth implant in a 196-d experiment. On the 1st d of the experiment, 40 calves were castrated chemically using Chem-Cast (active ingredient: lactic acid 88% wt/wt), and 40 were castrated surgically. Twenty calves on each castration treatment were implanted with STEER-oid on d 1 and reimplanted on d 121 while 20 calves on each treatment were not implanted on either date. Chemical castration resulted in significantly lower scrotal edema and a trend toward increased rate of gain at d 28. Castration treatment did not affect 196-d rate of gain and weaning weights of calves. On d 121, bilateral castration was determined in 30 of 40 chemically castrated calves, a condition that persisted on d 196, resulting in a 75% castration rate. Implanted calves had rates of gain that were 14, 6, and 4% higher, respectively, on d 28, 121, and 196 compared with unimplanted calves.

Comparative performance of straightbred and crossbred (F1) sires.

The first phase of this study was the production of contemporary straightbred (SB) and reciprocal crossbred (F1) bulls by mating Angus (A) bulls to A and Santa Gertrudis (SG) cows and SG bulls to SG and A cows. Of the bulls produced during the 4-yr period, those used for breeding included 15 A, 15 SG, 8 A X SG and 8 SG X A. For 205-d weight and weight/day of age (W/DA) postweaning, A X SG had higher (P less than .05) performance than SG X A bulls and SG had higher (P less than .05) performance than A bulls. There was no difference (P greater than .05) between SG and A X SG for 205-d weight, postweaning average daily gain (ADG) or postweaning W/DA. Heterosis estimates were 5.2 (P less than .10), 9.9 (P less than .01) and 5.8% (P less than .01) for 205-d weight, postweaning ADG and W/DA, respectively. The second phase of this study was the comparison of SB and F1 bulls for reproductive and progeny performance by exposing them as yearlings to 25 Polled Hereford cows each. There were no differences (P greater than .05) among the four sire groups for proportion of cows exposed that had a calf, had a live calf or weaned a calf. Reproductive performance of sires also was evaluated in terms of number of days (NOD) from the beginning of the breeding period until calves were born. The NOD for calves by SG was greater (P less than .05) than for calves by A or F1 sires. Compared with calves from SB sires, the NOD for calves from A X SG and SG X A sires were 5.0 and 10.6 d (P less than .05) lower. Differences among sires within year and breeding of sire were significant for all preweaning traits and for W/DA postweaning of their progeny. The SG-sired calves were heavier (P less than .05) for birth and 205-d weight and had higher (P less than .05) postweaning ADG than A-sired calves. Mean performance of calves by reciprocal F1 sires did not deviate (P greater than .05) from the mean performance of those by SB sires. Calves by A X SG sires had higher (P less than .05) 205-d weight, postweaning ADG and W/DA than calves by SG X A sires. Results indicated that the primary genetic effects responsible for differences in performance of calves sired by F1 vs SB bulls were mean transmitted and mean heterotic effects.(ABSTRACT TRUNCATED AT 400 WORDS)

Grading and rotational crossbreeding of beef cattle. I. Reproductive performance.

Purebred Angus (A), Polled Hereford (PH) and Santa Gertrudis (SG) bulls were mated to grades, two-breed and three-breed rotational crosses of these breeds (seven herds) to produce three generations (G1, G2 and G3) of calves. The grade A and PH cows were higher in A and PH breeding, respectively, than grade SG cows were in SG breeding. Reproductive performance among grade and rotational-cross herds was evaluated for herd differences, heterosis and effects of various genetic components. For cows that produced G1 calves, the proportion of cows that calved, had a live calf and weaned a calf was higher (P less than .01) for those that calved compared with those that failed to calve the previous year. For cows that produced G2 and G3 calves, previous year's calving status did not affect (P greater than .05) reproductive performance. Grade A and PH were similar (P greater than .05) in reproductive performance during G1, G2 and G3. As generations advanced, SG decreased in reproductive performance. Except for the PH-SG rotational cross in G3, the A, PH and all two-breed rotational crosses and the three-breed rotational cross generally were similar (P greater than .05) for the three reproductive traits during each generation. Within generations, reproductive performance was similar (P greater than .05) between rotations within each of the two-breed rotational cross herds. For the three-breed rotational cross herd, differences due to rotation generally were not significant during G1 and G2, but for G3, the SG sires were associated with lower (P less than .05) reproductive performance for each of the three reproductive traits compared with A and PH sires. Heterosis percentages generally were positive but not significant for each of the three reproductive traits. On the basis of additive and maternal effects of A and SG expressed as deviations from PH, the only genetic component that significantly affected reproductive performance was the detrimental additive effect of SG in G2 and G3 for each of the three reproductive traits. Also, there was a consistent negative relationship between breed additive and maternal components for each of the three reproductive traits during each generation. Only 4 to 7% of the variation in reproductive performance was accounted for in the analyses that included breed additive, breed maternal, heterosis and average maternal heterosis effects. Averaged over generations, from .1 to .4% additional variation was due to factors that may have included specific maternal heterosis, epistasis and linkage.

Grading and rotational crossbreeding of beef cattle. II. Calf performance to weaning.

Purebred Angus (A), Polled Hereford (PH) and Santa Gertrudis (SG) bulls were mated to grades, two-breed and three-breed rotational crosses of these breeds (seven herds) to produce three generations (G1, G2, G3) of calves. Birth weight and weaning traits were evaluated for herd differences, heterosis and effects of various genetic components. For each generation, the mean birth weight of SG exceeded that of PH which exceeded A (P less than .05). Averaged over generations, A and PH performed similarly for daily gain, 205-d weight and 205-d weight/cow exposed while SG exceeded A and PH for these traits. For feeder score, the breeds ranked A, PH, SG. For birth weight, daily gain, 205-d weight and 205-d weight/cow exposed, breeds ranked SG, PH, A for average additive genetic effects on the traits. Heterozygotic effects due to breed crosses, averaged over the three generations, were positive for all traits and generally significant, with PH X SG displaying more heterosis than the other two crosses. The maternal effects for A and SG were greater than PH for all traits except birth weight. Of the traits studied, from 12 (205-d wt/cow exposed) to 52% (205-d wt) of the variation averaged over generations was accounted for by a partial regression model that determined breed additive, breed maternal, heterosis and average maternal heterosis effects. Also averaged over generations, from .3 (205-d wt/cow exposed) to 1.7% (avg daily gain) additional variation was due to factors that may have included specific maternal heterosis, epistasis and linkage.

Colon replacement of the esophagus for congenital and benign disease.

Over the past 28 years, one of us (W. E. N.) has reconstructed the esophagus with the right colon for congenital and benign disease in 84 patients. The first patient in the series, who was operated on in 1955, remains asymptomatic. Nine patients had congenital tracheoesophageal fistula with atresia; 4, esophageal varices; 30, advanced obliterative esophagitis; and 23, corrosive destruction. In 7, severe esophagitis followed esophagogastrectomy; 4 had unsuccessful operations for achalasia; and 7 had colon bypass following esophageal perforation. Eleven early nonfatal complications occurred. Late nonfatal complications were seen in 6 patients. There were 4 early deaths (4%): following dehiscence of an intrathoracic esophagocolic anastomosis and 1 due to peritonitis. Four individuals died over the years, and 5 patients were lost to follow-up. The late results in 71 patients show that 60 (84.5%) believe they have a satisfactory result. Nine (13%) individuals are symptomatic, and 2 (2.8%) must be classified as failures. Early complications have been minimized by using preoperative intestinal angiography, anastomotic stapling techniques, and the Doppler study intraoperatively to prognosticate colon blood flow. Several important observations have been made: anastomosis in the neck is preferable; the transplanted colon dilates from loss of motor activity but is functionally adequate; an isoperistaltic segment is preferable, but an antiperistaltic implant suffices; colonic mucosa is relatively resistant to acid-peptic digestion; and hyperalimentation is mandatory in very ill and debilitated patients.

Reconstruction of the trachea and stem bronchi with Neville prosthesis.

Fifty-four patients with tracheal stenosis due to benign stricture and malignancy underwent airway reconstruction with a molded Silicone prosthesis (Neville Prosthesis). In 40 patients, the trachea was reconstructed with a straight prosthesis; of these 29 had a postintubation stricture and 11 a malignancy. In the former group, there was one early death from erosion of the innominate artery and five late deaths from a variety of causes. The postoperative complications were related to granulomas at the anastomotic site in four patients and were due to the use of non-absorbable suture material. Subglottic granulomas occurred in two patients and were successfully treated with fulguration. The lesion was resected and the trachea reconstructed with the prosthesis in eight individuals, five of whom are alive, one to six years postoperatively. Of the three patients, in whom the prosthesis served as an intraluminal stent, one who received irradiation is alive three years after operation. In 14 patients, in whom a carinal resection was performed for malignancy, five individuals are alive, from one to eleven years after surgery. There were four suture line granulomas in the entire group. All of the deaths were attributable to residual or disseminated cancer.

Aortotomy site infections: case presentation and review of the literature.

A patient with Aspergillus fumigatus infection involving an aortotomy site with multiple peripheral emboli following implantation of an aortic valve prosthesis for rheumatic heart disease is described. Eleven aortotomy site infections are reviewed from the literature. Eight cases were caused by fungi with Aspergillus sp accounting for four cases. Presenting symptoms were nondiagnostic and multiple. However, the diagnosis of aortotomy site infection should be entertained in patients who have had aortic valve surgery who develop fever and embolic phenomena with or without positive blood cultures coupled with no evidence of valve dysfunction, and who respond inappropriately to antibiotic therapy. Ten of the 11 patients reviewed from the literature died. Therapy should be directed at early recognition followed by prompt early surgery combined with the use of proper antimicrobial agents directed against the isolated microorganism.

Atherosclerotic aneurysms of the subclavian artery.

The case reports of three adult men, in whom four atherosclerotic aneurysms of otherwise normal subclavian arteries were detected in the absence of thoracic outlet syndrome or a history of trauma, are detailed. Two patients complained of supraclavicular discomfort--one having a history suggestive of peripheral arterial emboli and the other was asymptomatic. These aneurysms can be resected safely using a supraclavicular incision with resection of the medial clavicle. In cases requiring more proximal arterial control, median sternotomy is advisable. Our one patient with bilateral atherosclerotic aneurysms appears to be the first such reported case in the surgical literature.