Characterization of estrogen-trenbolone acetate implants on tenderness and consumer acceptability of beef under the effect of 2 aging times

Anabolic steroid implants are commonly used to increase growth performance and carcass leanness. The objective of this study was to determine the effects of various trenbolone acetate implants on Warner-Bratzler shear force (WBSF), slice shear force, and consumer palatability ratings for USDA Choice and Select beef strip steaks aged for 14 and 21 d from cattle implanted before slaughter. Beef steers (n = 1,740) were subjected to the following treatments: 1) nonimplanted control (CON); 2) Revalor-IS on d 0 and Revalor-S on d 70 (IS/S); or 3) Revalor-XS (RXS) on d 0, and were randomly assigned to pens within blocks. A subsample of USDA Choice (n = 82) and USDA Select (n = 81) carcasses was selected. Strip loins from these carcasses were collected, and steaks measuring 2.54 cm were fabricated and aged for 14 or 21 d postmortem. Select steaks aged 14 d from RXS cattle had decreased (P < 0.05) WBSF values compared with IS/S steaks, but CON steaks did not differ from either implant treatment. Warner-Bratzler shear force did not differ among treatments (P > 0.05) from USDA Choice steaks aged 14 and 21 d or from Select steaks aged 21 d. Consumer scores for flavor and overall liking for USDA Choice 14-d aged RXS steaks were less (P < 0.05) than CON steaks; however, there were no differences between RXS, IS/S, and CON for tenderness or juiciness, or for tenderness and overall acceptability. Select steaks aged 14 d from IS/S cattle had less (P < 0.05) tenderness, tenderness acceptability, overall acceptability, overall liking, juiciness, and flavor scores than RXS and CON steaks; however, consumers also rated RXS steaks less for tenderness, juiciness, and tenderness acceptability when compared with CON steaks. Consumer scores for overall liking, flavor, and tenderness for USDA Choice steaks aged 21 d from RXS, IS/S, and CON did not differ. However, implant affected (P < 0.05) overall liking, flavor, juiciness, and tenderness for USDA Select steaks aged 21 d. Even so, there were no differences between RXS, IS/S, and CON steaks for tenderness or overall acceptability for steaks aged 21 d, regardless of quality grade. Results indicated that tenderness differences exist among implant strategies when strip steaks were aged 14 d; however, tenderness and overall consumer acceptability were only influenced by implant in Select steaks aged 14 d. Furthermore, aging for 21 d can minimize and even eliminate implant differences in WBSF and slice shear force, as well as tenderness and overall consumer acceptability.     

Weaning pigs at an early age decreases cellular immunity

An experiment involving 118 pigs was conducted to evaluate the influence of weaning pigs at four different ages on in vivo and in vitro cell-mediated immunity. One-half of each litter was weaned at 2, 3, 4 or 5 wk of age; the other one-half remained with the sow as nonweaned controls. Phytohemagglutinin skin-test responses were determined on all pigs. Blastogenic responses of mitogen-stimulated lymphocyte cultures were determined before and after weaning. The intradermal response to phytohemagglutinin was reduced (P less than .001) in pigs weaned when 2 or 3 wk old and was suppressed (P less than .05) in those weaned when 4 wk old. In vivo cellular immunity was not altered by weaning in 5-wk-old pigs. The capability of lymphocytes to undergo blastogenesis in response to phytohemagglutinin was decreased in pigs weaned at 2 and 3 wk of age (P less than .001 and P less than .01, respectively). Pokeweed mitogen-stimulated blastogenesis was lower (P less than .01) in pigs weaned at 2 wk of age. Mitogen-stimulated lymphocyte blastogenesis was similar (P greater than .10) in control pigs and those weaned when 5 wk old. These data suggested that weaning pigs when younger than 5 wk old causes physiological changes detrimental to cellular immune reactivity. Those changes could alter disease susceptibility in young pigs.     

Response to ractopamine-hydrogen chloride is similar in yearling steers across days on feed

Yearling steers (n = 2,552; 314 kg of initial BW) were used to evaluate the effects of ractopamine-HCl (RAC) and days on feed on performance, carcass characteristics, and skeletal muscle gene expression in finishing steers. Treatment groups included serial slaughter dates of 150, 171, or 192 d on feed. Within each slaughter date, steers either received RAC (200 mg/steer) daily for the final 28 d or were not fed RAC. All steers were initially implanted with Revalor-IS and were reimplanted with Revalor-S after 75 d on feed. At slaughter, muscle samples from the semimembranosus were collected for mRNA analysis of the beta-adrenergic receptors (beta-AR). Ractopamine administration increased (P < 0.05) ADG, G:F, and HCW and increased (P = 0.08) LM area. Ractopamine did not affect the dressing percentage, USDA yield grade, or quality grade (P > 0.3). There was no change in overall feed intake across the entire feeding period; however, feed intake was increased during the 28-d period during which the steers were fed RAC (P < or = 0.05). Greater days on feed decreased (P < 0.05) ADG, G:F, DMI, and the number of yield grade 1 and 2 carcasses. Also, greater days on feed increased (P < 0.05) HCW, dressing percentage, and the number of prime and choice carcasses, as well as the number of yield grade 4 and 5 carcasses. Increasing days on feed decreased (P < 0.05) the abundance of beta(1)-AR and beta(3)-AR mRNA and increased (P < 0.05) the abundance of beta(2)-AR mRNA in skeletal muscle samples obtained at slaughter. Ractopamine had no effect (P > 0.10) on the abundance of beta(1)-AR or beta(3)-AR mRNA, but tended (P = 0.09) to increase beta(2)-AR mRNA. Additional time-course studies with primary muscle cell cultures revealed that advancing time in culture increased (P < 0.001) beta(2)-AR mRNA but had no effect (P > 0.10) on beta(1)-AR or beta(3)-AR mRNA. We conclude that days on feed and RAC are affecting beta-AR mRNA levels, which could, in turn, impact the biological response to RAC feeding in yearling steers.     

Effects of dietary zilpaterol hydrochloride on feedlot performance and carcass characteristics of beef steers fed with and without monensin and tylosin

A feedlot experiment was conducted under commercial conditions in the Texas Panhandle using 3,757 feedlot steers (average of 94 steers/pen) to evaluate the effects of feeding zilpaterol hydrochloride with or without monensin and tylosin on feedlot performance and carcass characteristics. The experiment was conducted using a randomized complete block design. Treatments were arranged as a 2 (no zilpaterol vs. zilpaterol) x 2 (monensin and tylosin withdrawn vs. monensin and tylosin fed during the final 35 d on feed) factorial. Steers were fed for a total of 161 to 167 d, and treatments were administered during the final 35 d that cattle were on feed. When included in the diet, zilpaterol, monensin, and tylosin were supplemented at 8.3, 33.1, and 12.2 mg/kg (DM basis), respectively. Zilpaterol was included in the diet for 30 d at the end of the finishing period and withdrawn from the diet for the last 5 or 6 d cattle were on feed. Cattle were harvested and carcass data collected. There were no zilpaterol x monensin/tylosin interactions (P >or= 0.12) for ADG or G:F. Feeding zilpaterol increased ADG (P < 0.001) by 0.20 kg and G:F (P < 0.001) by 0.029 kg/kg during the last 35 d on feed. Likewise, when feedlot variables were measured throughout the entire 161- to 167-d feeding trial, ADG (3.4%; P < 0.001) and G:F (3.9%; P < 0.001) were increased. Feeding zilpaterol increased (P < 0.001) dressing percent and HCW and decreased (P < 0.001) total liver abscess rate compared with controls. In addition, zilpaterol increased (P < 0.001) LM area by an average of 8.0 cm(2). There was a zilpaterol x monensin/tylosin interaction (P = 0.03) for marbling score. Zilpaterol decreased (P < 0.001) marbling score regardless of monensin and tylosin treatment, although withdrawal of monensin and tylosin for 35 d decreased marbling to a greater extent (31 vs. 17 degrees). Zilpaterol decreased (i.e., improved; P < 0.001) calculated yield grade regardless of monensin and tylosin treatment, but feeding zilpaterol in combination with the withdrawal of monensin and tylosin for 35 d decreased calculated yield grade to a greater extent (0.49 vs. 0.29) compared with the zilpaterol, monensin, and tylosin combination treatment (zilpaterol x monensin/tylosin interaction, P = 0.03). Results suggest that monensin and tylosin can be withdrawn from the diet during the zilpaterol feeding period (final 35 d on feed) with minimal effect on animal performance, although feeding zilpaterol in combination with monensin and tylosin seemed to moderate effects on carcass quality.     

Analysis of post-partum fertility in mares on a Thoroughbred stud in southern Victoria

This project surveys the reproductive performance of 154 foaling Thoroughbred mares on a commercial stud in southern Victoria. Of these, 96 were served on foal heat (FHS) and 58 were served at a subsequent prostaglandin-induced oestrus (PGS). The PGS group of mares performed more favourably in all aspects except the foaling-to-conception interval where there was a 9.4 day advantage to the FHS group. The first service conception rate in the FHS group was 47.9% compared with 55.2% in PGS mares. Second heat period conception rates were 46% vs 57.7% for FHS and PGS mares, respectively. Overall conception rates at the end of the breeding season were 83.3% in the FHS group and 89.7% in the PGS group. Pregnancy losses before day 45 and after day 45 were 10% and 9.3% in FHS mares and 3.9% and 3.6% in the PGS mares. Served oestrous periods per conception numbered 1.7 and 1.4 in the FHS and PGS groups, respectively.     

Temperature effects on dormancy,bud break and spear growth in asparagus (Asparagus officinalis L.)

Summary

The effects of the length of chilling, chilling temperature and growing temperature on dormancy of asparagus crown buds and subsequent rates of spear growth were examined. The results showed that prior chilling enhanced bud break at low growing temperatures and stimulated the growth of spears.Thus, chilling should facilitate commercial production by hastening bud break and spear growth rates at lower temperatures. If sufficient chilling was given, the minimum temperature for rapid bud break was approx. 12.5°C for ‘Rutgers Beacon’ and ‘Jersey Giant’, and around 10°C for ‘UC 157’ and ‘Apollo’. The optimum chilling temperature appeared to be closer to 5°C than to 10°C or 2°C for ‘Rutgers Beacon’ plants grown at 12.5°C. Increasing the growing temperature had a significant effect on the relative spear growth rate (RSGR) in all cultivars. Prior chilling had no effect on the RSGR for ‘Dariana’ and ‘Apollo’; but, for ‘UC 157’, chilling plants at 5°C for 5 or 10 weeks increased growth rates at 12.5°C and at 20°C. These results demonstrate that release of bud dormancy and spear growth rates depended not only on the growing temperature, but also, at least in some cultivars at some temperatures, on the duration and temperature of chilling during the previous Winter.     

Outbreaks of Salmonella enterica infections linked to animal contact: Demographic and outbreak characteristics and comparison to foodborne outbreaks—United States, 2009–2014

In the United States, multistate Salmonella outbreaks are most commonly linked to a food source; however, contact with live animals can also result in outbreaks of human illness. To characterize Salmonella outbreaks linked to animal contact and examine differences compared to foodborne outbreaks, we analysed data reported to the Centers for Disease Control and Prevention through the National Outbreak Reporting System (NORS) from 2009 to 2014 with a primary mode of transmission listed as “animal contact” or “food.” Four hundred and eighty‐four outbreaks with animal contact or foodborne transmission were reported through NORS; of these outbreaks, 99 (20.5%) resulted from Salmonella transmission through animal contact and 385 (79.5%) resulted from foodborne transmission, which resulted in 3,604 (19.8%) and 13,568 (80.2%) illnesses, respectively. A higher proportion of illnesses among children aged <1 year and children aged 1–4 years were linked to animal contact outbreaks compared to foodborne outbreaks (15.2% vs. 1.4%, p < 0.01 and 24.5% vs. 5.6%, p < 0.01, respectively). Illnesses resulting in hospitalizations (OR: 1.81, 95% CI: 1.62, 2.02) were more likely to be associated with animal contact compared to food. Animal contact outbreaks reported to NORS were more likely to be multistate compared to foodborne outbreaks (OR: 5.43, 95% CI: 3.37, 8.76) and had a longer median duration (99.0 days vs. 9.0 days, p < 0.01). Characterizing the differences between outbreaks of illness linked to animal contact and outbreaks linked to food provides useful information to investigators to improve public health response.