Influence of Propionate Salt Levels on Young Cow Reproductive Performance

A supplementation study was conducted to evaluate level of propionate salt (Ca-propionate) on young cow performance over two years. One hundred-twenty cows were allocated to one of three treatments at calving. Propionate salt was incorporated in a protein supplement at a rate of 0, 80 or 160 g/d. Cows were individually supplemented twice weekly at 2 lbs/d. In year 1, cows had access to pasture and hay. In year 2, cows had access to a native range pasture. Blood was collected weekly and analyzed for progesterone (P4) to determine postpartum interval (≥1 ng P4/ml). Weights and body condition scores (BCS) were assigned at calving, end of supplementation, start of breeding season, and weaning. Cow weight and BCS changed over time through the study (P \u3c 0.01 but was not affected (P \u3e 0.10) by treatment. Calf weight was not different (P \u3e 0.10) between treatments. Calf weight increased through the study (P \u3c 0.01). Pregnancy rates did not differ between treatments (P \u3e 0.10 but were affected by cow age (P\u3c0.01, 77% and 100% for 2- and 3-year-olds, respectively). In year 1, the percentage of cows initiating estrous cycles before the breeding season was greater (P\u3c0.05) for cows receiving 160 g (47.6%) compared to 0 g (15.6%) of propionate salt and tended to be greater than cows receiving 80 g (P\u3c0.10, 20.0%). Based on ultrasonography, 3-year-old cows conceived earlier (P\u3c0.01, 184 d) than 2-year cows (207 d). In year 2, postpartum anestrous interval (P = 0.70), percentage of cows initiating estrous cycles before the breeding season (P = 0.54), conception rate to AI (P = 0.68), and season-long pregnancy rates (P = 0.87) were not different among treatments. In summary, propionate salt can influence reproductive performance, however, response is not consistent

WILLINGNESS-TO-PAY FOR VALUE ADDED BRED HEIFER CHARACTERISTICS

Livestock Production/Industries,

Effects of Molybdenum Supplementation on Performance of Forage‐fed SteersReceiving High‐sulfur Water

There has been on‐going research in the area of the consumption of high‐sulfur (S) water by steers grazing rangeland as well as forage‐fed steers in a feedlot setting. During the summer of 2009, a trial was conducted on the effects of high‐S water in finishing steers supplemented with molybdenum (Mo). The main purpose of the research was to gather data that may aid in the formulation of a supplement to counteract the negative effects of high‐S water consumed by ruminant livestock species in areas where sulfur concentration in water sources is a risk to animal health and performance. The specific focus of this trial was to determine whether the feeding of supplemental Mo would improve animal health and performance by decreasing the formation of hydrogen sulfide gas (H2S) in the rumen. Yearling steers (n=96) were used for a 56‐d trial. The trial consisted of 3 treatment groups; a low‐S water group and two high‐S water groups. One high‐S water treatment group received the same pellet that the low‐S group was given and the other high‐S water treatment group received a pellet with supplemental Mo included. Rumen gas cap H2S was collected on d ‐1, 29 and 57. Weights were recorded on d ‐2, ‐1, 29, 56 and 57. There were no differences between treatments in water intake (P= 0.719), but feed intake was reduced in the steers receiving the supplemental Mo (P \u3c 0.001). There was a significant difference in ruminal H2S due to treatment (P= 0.014), with higher ruminal H2S in the steers receiving the supplemental Mo. Steers receiving the Mo supplement had lower ADG than steers in the other treatments (P= 0.009). Throughout the duration of the trial, two steers were removed from the trial due to advanced symptoms of sulfur‐induced PEM (sPEM) from the high‐S treatment with no supplemental M

Effects of Zilpaterol Hydrochloride Supplementation on Growth Performance,Carcass Characteristics and Production Economics of SteersDiffering in Breed Composition

The β–adrenergic agonist zilpaterol hydrochloride (ZH) affects skeletal muscle growth, but little is known if this response is influenced by differences in genetic background of cattle. The objective of this study was to determine the effects of ZH on growth, carcass characteristics and production economic responses of Angus-sired (ANG) and SimAngus-sired (SIMANG) steers. Pens within each block × breed composition were randomly assigned to either ZH (8.3 ppm of DM; fed for the final 20 d before slaughter) or control (CON; 0 ppm ZH). Steers were ultrasounded before ZH inclusion and following withdrawal to determine the influence of ZH on change in ribeye area (REA), fat thickness and percent intramuscular fat (IMF). Carcass and feedlot performance data were collected and used to determine breed composition and ZH effects on economic responses. The interaction of breed composition × ZH had no influence on measured responses. Breed composition did not influence change in ultrasound measurements during the ZH feeding period or feedlot performance. Carcasses from SIMANG steers had larger REA and improved YG, while ANG steers had increased marbling scores. SimAngus-sired steers produced a greater percentage of YG 2 and a lower percentage of YG 3 carcasses than ANG steers. A greater proportion of ANG carcasses were classified as upper 2/3 Choice while a greater proportion of SIMANG carcasses were included in the lower 1/3 Choice designation. Carcass value per cwt was greater for ANG compared to SIMANG carcasses while other economic responses were similar. Feeding ZH improved ADG, YG, and REA and resulted in increased YG 2 carcasses. Total carcass value was greater for ZH compared to CON. While CON had increased IMF during ZH feeding, this did not manifest into differences in QG. Breed composition influenced carcass grid premiums, but not overall carcass value. Feeding ZH improved carcass value by increasing HCW. Responses among breed composition were as expected for ANG vs SIMANG cattle types. The resultant economic effect was that grid premiums for higher-grading ANG cattle were offset by larger HCW for SIMANG, leading to similar overall carcass values. Finally, the influence of ZH on growth and carcass traits was as expected with increased carcass value being realized through heavier HCW

The Effects of Intensive Early Stocking and Early Weaning on the Onset of Puberty and Reproductive Success in Beef Replacement Heifers

Management practices utilizing genetics, nutrition, and growth have commonly been studied to maximize the lifetime productivity of female beef cattle. However, heifers managed to have their first calf by 24 months of age have the greatest chance of achieving maximum lifetime productivity. One way for a heifer to calve by 24 months of age is to decrease the age at which she reaches puberty. Heifers reaching puberty 1 to 3 months before exposure to breeding maximized conception success, as was shown when heifers bred during their third estrus were 21% more likely to conceive than heifers that were bred during their first or second estrus. Also, heifers fed a high-energy diet during the post-weaning period displayed a decreased age at puberty and an increased pregnancy rate. Additionally, early-weaned heifers fed a high-energy diet at an early age reached puberty at younger ages than those fed a low-energy control diet or those fed a high-energy diet beginning at six months of age. We hypothesized that heifers that were weaned at 120 days of age and provided a high-energy diet compared to the diet consumed by heifers weaned at a more conventional time of 205 days of age would display puberty at an earlier age and have improved first service conception and overall pregnancy rate

Effects of Weaning Age and Winter Development Environment on Heifer Performance

Our objective was to determine if early weaning (about 125 d) vs. normal weaning (about 250 d) and wintering replacement heifers in drylot vs. rangeland affected heifer growth and reproductive performance. Heifer calves from the 2009 and 2010 calf crops (n = 104 and 73, respectively) were allocated to the 2 weaning treatments and then stratified by age into the 2 winter development treatments forming a 2 by 2 factorial arrangement of treatments. Heifers wintered in drylot received mixed grass and alfalfa hay (yr 1: 11.6% CP, 52.5% TDN; yr2: 12.3% CP, 53.4% TDN) plus 1.8 kg of a dried distiller’s grain (DDGS)-based supplement/hd/d (yr1: 22.7% CP, 75.8% TDN; yr 2: 25.4% CP, 76.7% TDN). Heifers wintered on rangeland also received 1.8 kg/hd/d of the same supplement. Over the winter, each treatment was allocated to a separate pen or pasture. After estrus synchronization and timed AI, all heifers were placed on rangeland to graze through the summer. During the summer of yr 1, heifers were allocated by winter treatment to 2 pastures, and in yr 2 all 4 treatment combinations were allocated to separate pastures. Responses measured were BW, ADG, pubertal status at initiation of estrus synchronization, and pregnancy status after breeding. Pubertal status was indicated by serum progesterone \u3e 1 ng/ml. A winter by weaning treatment interaction affected (P\u3c0.001) BW and ADG both years. During the winter months, range heifers were lighter and grew slower than drylot heifers, but BW did not differ due to winter treatments at the end of the summer. However, early-weaned heifers remained lighter than normal weaned heifers at the end of the summer. Weaning treatment affected (P=0.03) fall pregnancy rate (93.2%±4.0 and 74.7%±7.98 for early- and normal-weaning, respectively) in yr 2. In yr 1, there was a difference (P=0.006) between drylot and range heifers (92.7%±3.52 and 72.8%±6.47, respectively) in the proportion that obtained puberty before estrus synchronization. In conclusion, producers should consider important interactions between weaning and winter management practices when establishing a replacement heifer development program that best fits the goals of their operation

Effect of Feeding Interval on Finishing Performance of Beef Steers

It has long been accepted that optimal performance in beef cattle occurs when cattle are fed at a similar time each day. In fact, in Frederick Mumford’s Syllabus of Illustrated Lecture on Profitable Cattle Feeding published by the U.S. Department of Agriculture in 1905, Mr. Mumford stated, “Cattle should be fed at certain hours and in the same way. This cannot be varied 15 minutes without some detriment to the cattle.” Little research has been conducted examining interval of feed delivery. Most feedlot research examining feed delivery has focused on the comparison of once or twice daily feed delivery on animal performance. The current research examined beef steer finishing performance with stable or variable once daily feed delivery

Copper Supplementation of Grazing Yearling Steers Supplemented withMolybdenum While Consuming High‐sulfur Water

There has been on‐going research conducted by South Dakota State University in the area of the consumption of high‐sulfur (S) water by steers grazing rangeland. During the summer of 2009 a trial was conducted in cooperation with the University of Wyoming on the effects of copper supplementation of grazing pasture steers supplemented with molybdenum (Mo), while drinking high‐sulfur water. The main purpose of this experiment was to gather data that may aide in the formulation of a method to counteract the negative effects of high‐S water consumed by ruminant livestock species in areas where sulfur concentrations in water sources causes risk to animal health and performance. Yearling steers (n=120) were assigned randomly to 9 replicate groups, 3 replicates of 3 treatments for a 52 d experiment. All groups were provided with high‐S water containing on average 2,201 mg•kg‐1 of sulfate. Additionally, all treatment groups received 100 mg•kg‐1 of supplemental Mo as an antagonist that would bind excess S. Unfortunately, Mo also binds copper (Cu), indicating that supplemental Cu may be necessary. Therefore treatments differed in level of supplemental copper: treatments 1 through 3 received 0, 75, or 150 mg•kg‐1 of supplemental Cu, respectively. Prior to the trial, mid‐trial and at the conclusion of the trial, ruminal H2S gas cap levels were collected. Animal weights were recorded d ‐2, ‐1, 28, 52 and 53. Over the entire course of the experiment there was a significant difference in ADG due to treatment (P\u3c 0.001). There were no differences in water consumption as a result of treatment (P= 0.618). No differences were observed in ruminal H2S due to treatment. No animal losses occurred due to the consumption of high‐S water in this trial

Polybrominated Diphenyl Ether (PBDE) Levels in an Expanded Market Basket Survey of U.S. Food and Estimated PBDE Dietary Intake by Age and Sex

OBJECTIVES: Our objectives in this study were to expand a previously reported U.S. market basket survey using a larger sample size and to estimate levels of PBDE intake from food for the U.S. general population by sex and age. METHODS: We measured concentrations of 13 polybrominated diphenyl ether (PBDE) congeners in food in 62 food samples. In addition, we estimated levels of PBDE intake from food for the U.S. general population by age (birth through ≥60 years of age) and sex. RESULTS: In food samples, concentrations of total PBDEs varied from 7.9 pg/g (parts per trillion) in milk to 3,726 pg/g in canned sardines. Fish were highest in PBDEs (mean, 1,120 pg/g; median, 616 pg/g; range, 11.14–3,726 pg/g). This was followed by meat (mean, 383 pg/g; median, 190 pg/g; range, 39–1,426 pg/g) and dairy products (mean, 116 pg/g; median, 32.2 pg/g; range, 7.9–683 pg/g). However, using estimates for food consumption (excluding nursing infants), meat accounted for the highest U.S. dietary PBDE intake, followed by dairy and fish, with almost equal contributions. Adult females had lower dietary intake of PBDEs than did adult males, based on body weight. We estimated PBDE intake from food to be 307 ng/kg/day for nursing infants and from 2 ng/kg/day at 2–5 years of age for both males and females to 0.9 ng/kg/day in adult females. CONCLUSION: Dietary exposure alone does not appear to account for the very high body burdens measured. The indoor environment (dust, air) may play an important role in PBDE body burdens in addition to food

Targeting Toll-like receptor-4 to tackle preterm birth and fetal inflammatory injury

Every year, 15 million pregnancies end prematurely, resulting in more than 1 million infant deaths and long-term health consequences for many children. The physiological processes of labour and birth involve essential roles for immune cells and pro-inflammatory cytokines in gestational tissues. There is compelling evidence that the mechanisms underlying spontaneous preterm birth are initiated when a premature and excessive inflammatory response is triggered by infection or other causes. Exposure to pro-inflammatory mediators is emerging as a major factor in the 'fetal inflammatory response syndrome' that often accompanies preterm birth, where unscheduled effects in fetal tissues interfere with normal development and predispose to neonatal morbidity. Toll-like receptors (TLRs) are critical upstream gatekeepers of inflammatory activation. TLR4 is prominently involved through its ability to sense and integrate signals from a range of microbial and endogenous triggers to provoke and perpetuate inflammation. Preclinical studies have identified TLR4 as an attractive pharmacological target to promote uterine quiescence and protect the fetus from inflammatory injury. Novel small-molecule inhibitors of TLR4 signalling, specifically the non-opioid receptor antagonists (+)-naloxone and (+)-naltrexone, are proving highly effective in animal models for preventing preterm birth induced by bacterial mimetic LPS, heat-killed Escherichia coli, or the TLR4-dependent pro-inflammatory lipid, platelet-activating factor (PAF). Here, we summarise the rationale for targeting TLR4 as a master regulator of inflammation in fetal and gestational tissues, and the potential utility of TLR4 antagonists as candidates for preventative and therapeutic application in preterm delivery and fetal inflammatory injury.Sarah A Robertson, Mark R Hutchinson, Kenner C Rice, Peck-Yin Chin, Lachlan M Moldenhauer, Michael J Stark, David M Olson, Jeffrey A Keela