Influence of dental carcass maturity classification on carcass traits and tenderness of longissimus steaks from commercially fed cattle.

Two hundred beef carcasses were randomly selected by dental classification (zero, two, four, six, or eight permanent incisors) from a population of 11,136 carcasses harvested by a large commercial beef processor. Warner-Bratzler shear force and trained sensory panel evaluations of longissimus thoracis steaks as well as cooking and carcass traits were evaluated for differences among dental classes. No differences in Warner-Bratzler shear force (P = 0.60), sensory panel evaluations (P = 0.64) for tenderness, or percentage of total cooking loss (P = 0.73) were found among the five dental classes. Longissimus muscle color, USDA marbling score, hot carcass weight, adjusted fat thickness, longissimus muscle area, and USDA yield grade did not differ among the five dental classes. A significant dental classification x sex interaction indicated that heifers advanced in skeletal and overall maturity at a much faster rate than steers. An increase of intramuscular fat was associated (P < 0.05) with decreased shear force (r = -0.31), whereas darkening of the lean (r = 0.16), advancing lean maturity (r = 0.21), and increased evaporative cooking loss (r = 0.39) were associated (P < 0.05) with increased shear force values. Warner-Bratzler shear force measurements were not related to sensory panel overall tenderness scores. Carcass traits accounted for a relatively small proportion of the variation in tenderness of longissimus steaks, and dental classification was not related to tenderness.

A comparison of the USDA ossification-based maturity system to a system based on dentition.

Two studies using commercially fed cattle were conducted to determine the relationship of the USDA bone ossification-based maturity system to one based on the number of permanent incisors present at slaughter. These studies showed that 91.5 to 100% of cattle with zero permanent incisors (< 23.8 mo of age), 89.1 to 97.5% of cattle with two permanent incisors (23.8 to 30.4 mo of age), 75 to 82.2% of cattle with four permanent incisors (30.4 to 38.0 mo of age), 64 to 72.5% of cattle with six permanent incisors (38.0 to 45.3 mo of age), and 40% of cattle with eight permanent incisors (> 45.3 mo of age) were graded as A maturity by the USDA maturity classification system. Kappa tests revealed no statistical relationship between the dentition- and skeletal ossification-based maturity systems. Dentition-based maturity agreed with ossification/lean maturity for only 162 of 1,264 carcasses in Exp. 1 and only 54 of 200 carcasses in Exp. 2. Cattle with two, four, six, or eight permanent incisors were classified in more youthful categories of USDA bone ossification/lean maturity than they should have been. Male cattle were more likely to be misclassified into a younger age category by the USDA system than were female cattle. It seems that determining physiological maturity by number of permanent incisors rather than by the current USDA method of subjectively evaluating skeletal and lean maturity may prove to be a more accurate technique of sorting beef carcasses into less-variable age groups.

Azithromycin vs doxycycline in the treatment of non-gonococcal urethritis.

Azithromycin is a novel azalide macrolide active against Chlamydia trachomatis and Ureaplasma urealyticum. High persistent tissue concentrations allow short courses or even single doses to be considered. Sixty-two patients were studied, 19 received azithromycin 1 g in a single dose, 22 received azithromycin 500 mg in a single dose on day 1 followed by 250 mg once daily for 2 days and 21 received doxycycline 200 mg in a loading dose followed by 100 mg every 12 h for 7 days. Efficacy of these 3 regimens was compared in the treatment of non-gonococcal urethritis (NGU). Clearance of C. trachomatis from post-treatment cultures was satisfactory with all regimens. Response defined as the absence of symptoms and reduction in polymorphonuclear leucocytes in a Gram stained smear of urethral secretion to less than 5 cells per hpf (x 100 objective) was statistically better for the 3 day regimen of azithromycin than for the other 2 regimens. All treatments were well tolerated. Three days or single doses of azithromycin compared to 7 days of tetracycline (or 10-14 days as is often prescribed) have obvious advantages for patient compliance.

Episodic acyclovir therapy to abort recurrent attacks of genital herpes simplex infection.

Frequent recurrence of genital herpes simplex infection can be a distressing condition. Continuous suppressive oral acyclovir is effective but expensive. Hitherto episodic therapy has given disappointing results. An open comparative study of patient initiated therapy is reported here. Acyclovir 200 mg five times daily for five days aborted 44% of recurrences and shortened 38% by greater than or equal to 50%, giving useful response in 82% of 34 recurrences. Acyclovir 400 mg twice daily for five days aborted 60% and shortened 17% giving useful benefit in 77% of 20 recurrences. Acyclovir 200 mg twice a day for five days gave unsatisfactory results. Patients were selected for frequent recurrences and a recognized prodrome, and care was taken to help to identify early prodromal symptoms. In these patients acyclovir in dosages of 200 mg five times daily for five days and 400 mg bd for five days proved convenient and cost effective.

STD and contraception in adolescents.

The prevalence of sexually transmitted diseases (STDs) in adolescents is poorly documented, as published studies consider single diseases or subgroups of adolescents. To obtain a broader view we examined STDs in unselected adolescent boys and girls at two contrasting genitourinary medicine (GUM) clinics, a large one at St Thomas's Hospital in inner London, which serves commuters and an inner city population, the other a smaller one at Swansea in south Wales, which serves a mixed urban and rural population. Contraception was also assessed in the girls. The STDs in adolescents were compared with the total diagnoses in patients of all ages attending the two GUM clinics, and with total diagnoses in all patients attending GUM clinics in England and Wales. The most striking finding was that all adolescents had at least one infection, whereas 18% of diagnoses in patients of all ages were of no infection. This contrasts with results of previous studies of selected groups, which suggested that the prevalence of STDs is similar in adults and adolescents. The percentages of infections, other than herpes at both clinics and trichomoniasis at Swansea, were higher in adolescents than in patients of all ages. High incidences of pelvic inflammatory disease in London and genital warts at Swansea suggest future problems. Only 66% of adolescent girls practised contraception, and only 8% stated that condoms were used. All people caring for adolescents should consider whether they are sexually active and, if they are, whether they need contraceptive advice or referral to a GUM clinic.