Laminitis: Recognition of At-Risk Individuals,and Methods of Prevention

Even with the many advances made in the understanding of the pathophysiology, new treatments and preventative measures, laminitis continues to plague the equine population. Identification of risk factor and at-risk individuals remains the best approach with this disease.     

网球肘的预防和治疗

一晃十年过去了。至于2000-2009年间谁主网坛沉浮,不妨让数据说话。ATP十年十佳①罗杰·费德勒十年中的最强统治者,他已经15次征服大满贯赛场,用上百种方式来描述他的伟大也不为过。从2003年他在温网赢得职业生涯第一个大满贯冠军算起,之后的大满贯中有58%是他笑到最后。现在,他已经可以被称作史上最伟大的网球选手。     

Defoliation,nitrogen, and competition: effects on plant growth and resource allocation of Cleistogenes squarrosa and Artemisia frigida

Two species, Artemisia frigida Willd. (C₃, semishrub, and dominant on overgrazed sites) and Cleistogenes squarrosa (Trin.) Keng (C₄, perennial bunchgrass, and dominant or codominant on moderately grazed sites) were studied to determine the effects of defoliation, nitrogen (N) availability, competition, and their interactions on growth, biomass, and N allocation in a greenhouse experiment. The main treatments were: two nitrogen levels (N0 = 0 mg N pot^–1, N1 = 60 mg N pot^–1), two defoliation intensities (removing 60% of total aboveground biomass and no defoliation), and three competitive replacement series (monocultures of each species and mixtures at 0.5:0.5). Our results were inconsistent with our hypothesis on the adaptive mechanisms of A. frigida regarding the interactive effects of herbivory, N, and competition in determining its dominant position on overgrazed sites. Cleistogenes squarrosa will be replaced by A. frigida on overgrazed sites, although C. squarrosa had higher tolerance to defoliation than did A. frigida. Total biomass and N yield and ¹⁵N recovery of C. squarrosa in mixed culture were consistently lower than in monocultures, whereas those of A. frigida grown in mixtures were consistently higher than in monocultures, suggesting higher competitive ability of A. frigida. Our results suggest that interspecific competitive ability may be of equal or greater importance than herbivory tolerance in determining herbivore‐induced species replacement in semi‐arid Inner Mongolian steppe. In addition, the dominance of A. frigida on overgrazed sites has been attributed to its ability to shift plant‐plant interactions through gap colonization, root niche differentiation, and higher resistance to water stress.     

Relationship between weaning age and antibiotic usage on pig growth performance and mortality

A total of 2,184 pigs (DNA 600 × PIC L42) were used to evaluate the effects of weaning age and antibiotic (AB) use on pig performance from weaning to marketing in a commercial production system. Experimental treatments were arranged in a 3 × 2 factorial with main effects of weaning age (18.5, 21.5, or 24.5 d of age) and with the use of ABs or an antibiotic-free (NAE) program. At birth, pigs were ear tagged, and the date of birth and sex recorded. Pigs were weaned from a 4,000-sow farm over four consecutive weeks. Four weaning batches (one per week) of 546 pigs were used. Each weaning batch had one-third of pigs of each weaning age. Pigs were placed in pens by weaning age and then randomly assigned to an AB or NAE program. There were 14 replicate pens per treatment and 26 pigs per pen (13 barrows and 13 gilts). Pigs allocated to the AB program were fed a diet containing 441 mg/kg chlortetracycline (CTC) from day 8 to 21 postweaning. They were also administered 22 mg/kg of body weight (BW) of CTC via drinking water for five consecutive days after a porcine respiratory and reproductive syndrome outbreak during week 7 after weaning. In the first 42 d postweaning, increasing weaning age improved (linear, P < 0.001) BW at day 42, average daily gain (ADG), and average daily feed intake (ADFI). From weaning to 197 d of age, increasing weaning age increased (linear, P < 0.001) ADG and ADFI. Pigs on the AB program had greater (P = 0.031) ADG and ADFI compared with NAE pigs. An interaction (linear, P = 0.005) was observed for feed efficiency (G:F). When ABs were provided, increasing weaning age did not result in any change in G:F; however, in the NAE program, increasing weaning age increased G:F. Pigs on the AB program had lower (P < 0.001) total losses (mortality and removals) than those on the NAE program. Increasing weaning age marginally (linear, P = 0.097) decreased total losses. Increasing weaning age decreased (quadratic, P < 0.001) the number of pigs treated with an injectable AB but the AB program did not (P = 0.238). The weight sold (at 197 d of age) per pig weaned was increased (linear, P = 0.050) by increasing weaning age and by using AB in feed and water (P = 0.019). In summary, increasing weaning age linearly improved most of the pig performance criteria and relatively the short-term use of ABs reduced mortality and removals with both factors contributing to increased weight sold per pig weaned.     

Effects of dietary iodine value product on growth performance and carcass fat quality of finishing pigs

A total of 120 barrows (initial BW = 47.9 ± 3.6 kg; PIC 1050) were used in an 83-d study to determine the effects of dietary iodine value (IV) product (IVP) on growth performance and fat quality. Pigs were blocked by BW and randomly allotted to 1 of 6 treatments with 2 pigs per pen and 10 pens per treatment. Dietary treatments were fed in 3 phases and formulated to 3 IVP concentrations (low, medium, and high) in each phase. Treatments were 1) corn-soybean meal control diet with no added fat (low IVP), 2) corn-extruded expelled soybean meal (EESM) diet with no added fat (medium IVP), 3) corn-soybean meal diet with 15% distillers dried grains with solubles and choice white grease (DDGS + CWG; medium IVP), 4) corn-soybean meal diet with low CWG (medium IVP), 5) corn-EESM diet with 15% DDGS (high IVP), and 6) corn-soybean meal diet with high CWG (high IVP). On d 83, pigs were slaughtered and backfat and jowl fat samples were collected and analyzed. The calculated and analyzed dietary IVP values were highly correlated (r(2) = 0.86, P < 0.01). Pigs fed the control diet, EESM, or high CWG had greater (P < 0.05) ADG than pigs fed EESM + DDGS. Pigs fed the control diet had greater (P < 0.05) ADFI than pigs fed all other diets. Pigs fed EESM + DDGS and high CWG had improved (P < 0.05) G:F compared with pigs fed the control diet or DDGS + CWG. Pigs fed diets with DDGS had greater (P < 0.05) backfat and jowl fat IV, C18:2n-6, and PUFA and less SFA than pigs fed all other treatments. Pigs fed EESM had greater (P < 0.05) backfat and jowl fat IV, C18:2n-6, and PUFA than pigs fed the control diet, low CWG, or high CWG. Pigs fed low CWG or high CWG had greater (P < 0.05) jowl fat IV than control pigs. Feeding ingredients high in unsaturated fatty acids, such as DDGS and EESM, had a greater impact on fat IV than CWG, even when diet IVP was similar. Therefore, IVP was a poor predictor of carcass fat IV in pigs fed diets with different fat sources and amounts of unsaturated fats formulated with similar IVP. Dietary C18:2n-6 content was a better predictor of carcass fat IV than diet IVP.     

Testosterone concentration in the seminal plasma of cocks

Testosterone concentrations in the seminal plasma of cocks ranged from 0.46 to 5.05 ng/ml and were substantially lower than in blood plasma. No significant variation was noted in seminal plasma testosterone concentrations during the light phase of the day, whereas the concentration in blood declined over this period. Spermatozoal concentration and seminal testosterone decreased in the third sample of the semen collected sequentially at 3 h intervals. Testosterone concentrations in seminal plasma (1.57 +/- 0.17 ng/ml) and in the semen from the ductus deferens (1.34 +/- 0.24 ng/ml) were not significantly different.     

Transient hypersensitivity to soybean meal in the early-weaned pig

An experiment was conducted to determine whether baby pigs develop hypersensitivity to dietary soybean proteins. Thirty-two pigs were orally infused with either dried skim milk (5 g/d; control) or soybean meal (48% CP; 5 g/d) from d 7 to 14 after birth. Sows were fed a corn-corn gluten meal-based diet supplemented with lysine and tryptophan to avoid exposure of pigs to soybean proteins. Pigs were weaned at 21 d of age and fed diets containing either soybean meal or milk proteins until d 56. One half of the pigs were killed at 28 d of age and the rest at 56 d of age. Segments of small intestine were collected, and intraepithelial lymphocytes were isolated. At 28 d of age, pigs fed diets containing soybean meal had lower (P less than .05) villus height (221 vs 298 microns) and rate of gain (86 vs 204 g/d) than control pigs did. Pigs fed a diet containing soybean meal had higher (P less than .05) immunoglobulin G (IgG) titers to soybean protein than did pigs fed a milk protein-based diet. Blood and intestinal lymphocytes collected on d 28 and 56 did not exhibit any proliferative response when cultured with purified soy proteins (2.5 or 5 microns/ml). Phytohemagglutinin- and pokeweed mitogen-induced lymphocyte proliferations were higher (P less than .05) at d 56 than at d 28, but there were no differences attributable to protein source. There were no differences (P greater than .05) in skin-fold thickness measurements following intradermal injection with soy or milk proteins. Decreased villus height and increased serum IgG titers to soybean proteins coinciding with inferior performance of early weaned pigs fed diets containing soybean meal indicate that conventionally processed, commercial soybean meal may retain some antigens that can cause transient hypersensitivity in piglets.