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Animal breeding reports in the Journal of Animal Science (JAS) and in its predecessor, Proceedings of the American Society of Animal Production, were counted and categorized. In 22 volumes of the Proceedings of the American Society of Animal Production, 155 articles had animal breeding content, of which 54% were research reports, 17% extension communications, and 28% syntheses or reviews. Several of the latter featured advice from the livestock industry to the scientific community. Thirty-one percent of articles concerned swine, whereas beef cattle, dairy cattle, and sheep each accounted for an additional 20%. In the 67 yr of JAS publication, 3,045 research papers were identified with animal breeding content, nearly half of them published since 1990. Growth in publication output was modest during the 1950s, robust in the 1960s through 1980s, moderate in the 1990s, and static in the 2000s. Important topics included genetic resource evaluation (a subject in 55% of all manuscripts), genetic parameter estimation, selection programs, and nonrandom mating systems. Maternal effects and genotype x environment interactions were featured in 17 and 15% of all manuscripts, respectively, whereas 6% dealt with a simply inherited trait. Only 4% of manuscripts included economic analysis of a breeding program or intervention. Interest in molecular biology and biometry has surged in the 1990s and 2000s. Approximately 50% of all papers involved cattle, a fifth of which concerned dairy cattle or beef x dairy crossbreds. A quarter of papers concerned swine, 15% concerned sheep, and 3% considered laboratory rodents, with the proportional contribution of sheep research decreasing across time. Authors from the Midwestern and Southern sections of the American Society of Animal Science had greater proportional contributions than Western and Northeastern section authors, and contributions of university and state experiment station authors outnumbered those of USDA-ARS authors. The proportional contribution of international authors increased across time, reaching 45% for the 2000s, as that of university and experiment station authors decreased and that of USDA-ARS authors remained fairly constant. Subjective analysis suggested substantial levels of creativity, innovation, and cooperation in JAS animal breeding research, a strong international perspective, but also a marked degree of imitation and repetition in subject matter content.

Acute and subacute ruminal acidosis, bloat, liver abscesses, and polioencephalomalacia (PEM) were reviewed with respect to contributions published in the Journal of Animal Science (JAS) regarding these metabolic and digestive disorders in beef cattle. Increased grain feeding and expansion of the feedlot industry in the 1960s led to considerable research on acidosis, and early publications defined ruminal changes with acute acidosis. The concept of subacute acidosis was developed in the 1970s. Significant research was published during the 1980s and 1990s on adaptation to high-grain diets, effects of ionophores, and the development of model systems to study ruminal and metabolic changes in acidosis. Since 2000, JAS publications on acidosis have largely focused on individual animal variability in response to acid loads and the role of management strategies in controlling acidosis. Increased grain feeding also was associated with an increase in the incidence of liver abscesses, which were quickly linked to insults to the ruminal epithelium associated with acidosis. The role of antibiotics, particularly tylosin, in decreasing the incidence and severity of liver abscesses was a significant contribution of JAS publications during the 1970s and 1980s. Papers on bloat were among the earliest published in JAS related to metabolic and digestive disorders in cattle. Noteworthy accomplishments in bloat research chronicled in JAS include the nature of ruminal contents in legume and feedlot bloat, the role of plant fractions and microbial populations in the development of bloat, and the efficacy of poloxalene, ionophores, and, more recently, condensed tannins in decreasing the incidence and severity of bloat. Although less research has been published on PEM in JAS, early publications highlighting the association between PEM and ruminal acidity and the role of thiaminase in certain forms of the disorder, as well as more recent publications related to the role of sulfur in the development of PEM, are noteworthy contributions. Since the 1940s, outstanding and often-cited review articles have made JAS a highly visible source of information on these disorders. Thus, JAS has played a significant role as a repository for information pertaining to metabolic and digestive disorders in cattle and other ruminants, and it will no doubt continue to be a premier resource for information on these conditions during the second century of the American Society of Animal Science.

American Society of Animal Science members, publishing in Journal of Animal Science (JAS), completed research that resulted in understanding the estrous cycle of cattle, which led to the ability to inseminate cattle on a given day with pregnancy rates similar to those achieved by 21-d breeding by a fertile and sound bull. Research published in JAS led to understanding estrus, ovulation, the estrous cycle, and postpartum interval for cattle (1930s through 1960s) and hormonal factors affecting corpus luteum lifespan of cattle (1950s through 1980s). Research during the 1940s to 1960s, using gonadotropins and progesterone to manage the estrous cycle of cattle, established the concepts for estrous synchronization and stimulated commercial research directed at developing cost-effective progestogen estrous synchronization products, leading to commercially available products from 1967 through today (Repromix, melengestrol acetate, Syncro-Mate-B, controlled internal drug release). Prostaglandin F(2alpha) products were approved for estrous synchronization (1970s, 1980s), and GnRH products were approved for use in cattle to treat ovarian follicular cysts (1970s, 1980s). Research published in JAS was essential for understanding the biology of and potential value of both PGF(2alpha) and GnRH and contributed both to new knowledge and scientific bases for future Food and Drug Administration Center for Veterinary Medicine approval of those products. Research during the1980s through 2000s led to understanding ovarian follicular waves and described the timing of follicular recruitment, selection, dominance, and atresia; this research was essential for the ability to effectively manage follicles to achieve success with timed AI. The knowledge gained through research published in JAS resulted in development of the numerous estrous synchronization and breeding management protocols that are cost-effective and meet the breeding management needs of most beef and dairy enterprises.

One hundred years ago, there were more than 48 million sheep in the United States. In 1910, they were valued at $4/head, with 43% of income coming from the sale of sheep, lambs, and meat and 57% coming from wool. Over the years, fluctuations in this ratio have challenged the breeder and researcher alike. By 2007, sheep numbers had declined to 6.2 million, with the average sheep shearing 3.4 kg of wool (representing

Proteomics holds significant promise as a method for advancing animal science research. The use of this technology in animal science is still in its infancy. The ability of proteomics to simultaneously identify and quantify potentially thousands of proteins is unparalleled. In this review, we will discuss basic principles of doing a proteomic experiment. In addition, challenges and limitations of proteomics will be considered, stressing those that are unique to animal sciences. The current proteomic research in animal sciences will be discussed, and the potential uses for this technology will be highlighted.

Teaching has a long and varied history in the life of departments of animal science and the American Society of Animal Science. Some of the earliest reports from meetings of the society have strong indication that planning the curriculum was a prominent feature of the meetings. Teaching symposia were also included almost from the beginning. The society went through a lengthy period from the 1940s through most of the 1960s when teaching was not a prominent focus, but a symposium in 1968 appeared to be a catalyst for change, and, since that date, teaching has again been an important part of the meetings. In recent years, outstanding symposia and contributed papers have made the teaching section a vibrant entry. Departments of animal science have changed considerably since the early days in which "men taught boys" and the primary goal was to produce farmers. More female students, more urban students, interest in a wide variety of animals, and greatly diversified career goals have been emerging during the last few decades. Departments of animal science and the American Society of Animal Science are positioning to be able to respond to change and face the challenge of providing excellence in teaching during the next century.

Goat research in the United States has increased but at a rate less than that in production. Research on goat meat includes nutritional quality, packaging, color, sensory characteristics, and preslaughter management. Goat skins have value for leather, but quality of goat leather has not been extensively studied. Research in the production, quality, antibiotic residues, and sensory characteristics of goat milk and its products has aided development of the US dairy goat industry. Limited progress has been made in genetic improvement of milk or meat production. There is need to explore applications of genomics and proteomics and improve consistency in texture and functionality of goat cheeses. New goat meat and milk products are needed to increase demand and meet the diverse tastes of the American public. Despite research progress in control of mohair and cashmere growth, erratic prices and sale of raw materials have contributed to further declines in US production. Innovative and cooperative ventures are needed for profit sharing up to the consumer level. Internal parasites pose the greatest challenge to goat production in humid areas largely because of anthelmintic resistance. Study of alternative controls is required, including immunity enhancement via nutrition, vaccination, pasture management such as co-grazing with cattle, and genetic resistance. Similarly, the importance of health management is increasing related in part to a lack of effective vaccines for many diseases. Nutrition research should address requirements for vitamins and minerals, efficiencies of protein utilization, adjusting energy requirements for nutritional plane, acclimatization, and grazing conditions, feed intake prediction, and management practices for rapid-growth production systems. Moreover, efficient technology transfer methods are needed to disseminate current knowledge and that gained in future research.

Utilizing different dietary fiber sources has been studied in piglets to help mitigate post-weaning diarrhea and improve post-weaning performance. An experiment was conducted to investigate the effect of adding sugar beet pulp or a stimbiotic (Signis; AB Vista) on nursery pig performance. Barrows (n = 216; average initial BW = 5.1kg) were randomly allotted to one of three dietary treatments and fed a 4 phase feeding program; 1) Control (Con), Insoluble/Soluble fibre ratio (I/S), P1; 4.47, P2; 5.84, P3; 5.82, P4; 7.08. 2) High Soluble (HS) with sugar beet pulp added at 5% (P1 and P2) and 2.5% (P3 and P4) giving the following I/S ratio; P1; 2.63, P2; 2.91, P3; 5.02 and P4; 5.42. 3) Control plus stimbiotic added at 100 g/t (SIG). Pen weight and feed disappearance were recorded weekly to calculate ADG, ADFI, and G:F. Fecal score was visually ranked by pen daily from wean to 35 days. Blanket water medications were not provided. Instead, individual pigs that needed treatment were identified and injected with individual antibiotic interventions, and the number of interventions per pig was recorded. Performance data were submitted to ANOVA using JMP with mean separation by Tukey test and a contingency analysis was used to compare antibiotic injections. At day 14, pigs had a Rotavirus A and B challenge. Addition of HS or SIG reduced (P < 0.05) individual antibiotic treatments by 56 and 32% compared to the CON, respectively. No differences were observed in scour scores or overall ADG. Overall intake was greater (P < 0.01) in HS (0.560 kg) than CON (0.491 kg) or SIG (0.492 kg). Pigs fed SIG (0.671) had a better (P = 0.011) G:F over SBP (0.602), with CON (0.649) being intermediate. In conclusion, HS increased intake where stimbiotic improved feed efficiency, and both decreased antibiotic treatments.

The objective was to determine the influence of feed intake (FI) and fiber source on hindgut disappearance of energy and nutrients in pigs. Ten canulated barrows with an initial body weight (BW) of 38.3 ± 5.4 kg were allotted to a replicated 5 × 4 Latin square design with 5 treatments and 4 periods. A corn-soybean meal-based basal diet (BD) and 2 × 2 factorial treatment arrangement with 2 amounts of FI (9.0 and 4.5% × BW0.75) and 2 fiber sources of sugar beet pulp (SBP) and corn cob were used. Three diets were 1) a BD, 2) a diet replacing 30% of corn and soybean meal in BD with SBP as a source of soluble dietary fiber (SDF), and 3) a diet replacing 15% of corn and soybean meal in BD with corn cobs as a source of insoluble dietary fiber (IDF) to obtain a similar IDF concentration as in the SBP diet. Each period consisted of 7-d adaptation, 2-d fecal collection, and 2-d ileal collection. Apparent ileal digestibility (AID) of energy, dry matter (DM), organic matter (OM), and crude protein (CP) in SBP diet was less (P < 0.001) than that in corn cob diet, whereas AID of neutral detergent fiber in SBP were greater (P < 0.001) than in corn cob diet. Hindgut disappearance of energy, DM, OM, neutral detergent fiber, and acid detergent fiber in SBP diet was greater (P < 0.05) than that in corn cob diet. However, no interaction between FI and fiber source on the AID, apparent total tract digestibility, and hindgut disappearance of nutrients was observed. Overall, hindgut disappearance of nutrients in sugar beet pulp diet was greater than that in corn cob diet. However, the influence of feed intake or the interaction between feed intake and fiber source was not observed.

Lignocellulose is an alternative fiber source for dogs; however, it has not yet been studied as a feed ingredient for the nutrition of dogs. Eight adult Beagles were involved in the study, which consisted of 3 feeding periods of 8 to 12 wk each. All dogs received 3 different diets, which either had the same concentration of fiber sources (2.7% sugar beet pulp or lignocellulose) or were formulated for a similar concentration of approximately 3% crude fiber: 12% sugar beet pulp (highSBP; 3.1% crude fiber), 2.7% sugar beet pulp (lowSBP; 0.96% crude fiber), or 2.7% lignocellulose (LC; 2.4% crude fiber). Feces samples were collected at the end of each feeding period, and the apparent nutrient digestibility, daily amount, and DM content of feces and fecal cell numbers of relevant bacteria were analyzed. The daily feces amount was lower and the feces DM was higher when dogs were fed the LC diet and the lowSBP diet compared with the highSBP diet ( < 0.001). Apparent digestibility of CP, Na, and K was highest with the lowSBP diet followed by the LC and highSBP diets ( < 0.001). After feeding LC, the bacterial cell counts of spp., spp., and the cluster were reduced compared with feeding highSBP and even more reduced after feeding lowSBP ( < 0.001). The bacterial cell count of the cluster was lower in LC and lowSBP compared with highSBP ( < 0.001). The feces of dogs fed LC and lowSBP had lower concentrations of acetate ( < 0.001), propionate ( < 0.001), -butyrate ( = 0.015), total fatty acids ( < 0.001), and lactate ( < 0.001) compared with dogs fed highSBP. The concentration of -butyrate was higher in the feces of dogs fed with LC compared with dogs fed high and low sugar beet pulp (SBP; < 0.001). The pH of the feces of the LC-fed dogs was highest followed by lowSBP- and highSBP-fed dogs ( < 0.001). Depending on the concentration, the use of LC and SBP as fiber sources in dog feed has different impacts on the fecal microbiota and the apparent digestibility of nutrients. Therefore, different areas of application should be considered.

Two experiments were conducted to study the effects of inclusion of additional fiber in the Phase I diet on growth performance and nutrient digestibility in piglets reared under "optimal" or "poor" hygienic conditions. In both experiments, the design was completely randomized with a control diet that contained 2.2% crude fiber and 8 additional isonutritive diets that included 2.5 or 5.0% of sugar beet pulp (SBP), straw, oat hulls (OH), or wheat middlings (WHM). Preplanned polynomial contrasts were used to study the effects of 1) fiber inclusion (control diet vs. average of the 8 fiber-containing diets), 2) source of fiber, 3) level of fiber, and 4) interaction between source and level of fiber. In Exp. 1 (clean barn), fiber inclusion increased ( < 0.01) the incidence of postweaning diarrhea (PWD) and reduced ( < 0.05) feed efficiency and apparent total tract digestibility (ATTD) of all nutrients except that of CP, which was not affected. Piglet performance was not affected by source or level of dietary fiber. The ATTD of all nutrients decreased ( < 0.05) as the level of fiber increased and was lower in pigs fed straw or OH than in pigs fed SBP or WHM. The apparent ileal digestibility of GE and DM decreased ( < 0.05) with fiber inclusion, a reduction that was more pronounced ( < 0.05) with straw or SBP than with OH inclusion, with WHM inclusion being intermediate. Fiber inclusion did not affect villous height to crypt depth ratio of the ileum mucosa. The inclusion of 5% of a fiber source increased and counts in the cecum ( < 0.001) but the to ratio was not affected. In Exp. 2 (dirty barn), fiber inclusion did not affect piglet performance but tended to increase PWD ( = 0.07). Also, fiber inclusion reduced ( < 0.05) the ATTD of all dietary components except that of CP, which was not affected. Source and level of fiber did not affect ATTD of nutrients except for DM, which was greater for pigs fed SBP than for pigs fed straw ( < 0.05). In conclusion, in the current research, pigs reared under optimal hygienic conditions had lower incidence of PWD, better growth performance, and greater DM and GE digestibility than pigs reared under poor hygienic conditions. An excess of dietary fiber was more detrimental for all these traits in piglets reared under optimal hygienic conditions. The effects of the source and level of fiber on piglet performance was limited in the 2 experiments.

The objective of the present study was to compare digestion rates (kd) of NDF for different feeds estimated with the in situ method or derived from an automated gas in vitro system. A meta-analysis was conducted to evaluate how in situ derived kd of NDF related to in vivo digestibility of NDF. Furthermore, in vitro true digestibility of the feed samples incubated within filter bags or dispersed in the medium was compared, and kd for insoluble and soluble components of those feeds were estimated. Four different concentrates and 4 forages were used in this study. Two lactating Swedish Red cows fed a diet of 60% grass silage and 40% concentrate on DM basis were used for in situ incubations and for collection of rumen fluid. The feed samples were ground through a 2.0-mm screen before the in situ incubations and a 1.0-mm screen before the in vitro gas incubations. In situ nylon bags were introduced into the rumen for determination of kd of NDF. Additional kinetic data were produced from isolated NDF and intact samples subjected to in vitro incubations in which gas production was recorded for 72 h. Samples were weighed in the bottles or within filter bags (for fiber and in vitro studies) that were placed in the bottles. The interaction between feed and method was significant (P < 0.01); kd of NDF for grass hay tended (P = 0.06) to be less whereas kd of NDF for alfalfa, barley grain, canola meal, and dried sugar beet pulp were greater (P < 0.01) when estimated with the in situ method than from gas production recordings. The meta-analysis suggested that in situ derived kd of NDF were biased and underestimated in vivo digestibility of NDF. Digestion rates of the intact samples were lower for all feeds, except for the hay, when incubated within the bags compared with dispersed in the medium (P < 0.01). Less OM and NDF were digested for all feeds when incubated within bags than dispersed in the medium (P < 0.01). It is concluded from the in vitro study that microbial activity within the bags is less than in the medium. Significant interactions between method (in situ vs. in vitro) and feed suggest that one or both methods result in biased estimates of digestion kinetics.

The objective of this experiment was to test the hypothesis that differences in the digestibility of total dietary fiber among breeds of pigs is influenced by the type of fiber fed and also by the age of the pig. Five Meishan pigs (BW: 77.2 ± 15.2 kg; 5 mo old), 5 light Yorkshire pigs (BW: 80.1 ± 11.2 kg; 4 mo old), and 5 heavy Yorkshire pigs (BW: 102.1 ± 3.5 kg, 5 mo old) were surgically prepared with a T-cannula in the distal ileum. A corn-soybean meal diet (control) was formulated with 5 g•kg(-1) of titanium dioxide as an indigestible marker. Three additional diets were formulated by replacing 30% of the control diet with 30% of distillers dried grains with solubles (DDGS), soybean hulls, or sugar beet pulp, and 1 diet was formulated by replacing 15% of the control diet with 15% pectin. Each group of pigs was allotted to a 5 × 5 Latin square design, and pigs were fed the 5 experimental diets during five 14-d periods. Fecal samples were collected on d 12, and ileal digesta were collected on d 13 and 14 of each period. The apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of GE and nutrients in each ingredient were calculated using the substitution method. Hindgut disappearance was calculated as the difference between ATTD and AID. When fed the control diet, Meishan pigs tended (P < 0.10) to have a greater AID of GE and CP (78.6 and 80.3%, respectively) than light (77.0 and 78.9%, respectively) and heavy (75.7 and 76.9%, respectively) Yorkshire pigs, and they had a greater (P < 0.05) ATTD of DM, GE, and carbohydrates (89.2, 89.5, and 95.5%, respectively) than light (86.6, 86.4, and 92.4%, respectively) and heavy (87.0, 86.6, and 93.0%, respectively) Yorkshire pigs. The ATTD of DM, GE, CP, carbohydrates, and total dietary fiber in DDGS (75.4, 76.3, 81.3, 78.0, and 75.3%, respectively) was greater (P < 0.01) in Meishan pigs than in light (55.7, 58.5, 66.7, 49.2, and 39.0%, respectively) and heavy (59.8, 62.9, 70.0, 51.1, and 55.7%, respectively) Yorkshire pigs. There were no differences among the 3 groups of pigs in the ATTD of GE or nutrients in soybean hulls, sugar beet pulp, or pectin. The hindgut disappearance of DM and carbohydrates in DDGS by Meishan pigs (26.8 and 52.9%, respectively) was greater (P < 0.05) than in the light (10.0 and 22.8%, respectively) and Heavy Yorkshire pigs (12.2 and 20.0%, respectively), but for the other ingredients, no differences in hindgut disappearance among Meishan, light Yorkshire, and heavy Yorkshire pigs were observed. In conclusion, Meishan pigs have a greater ATTD of DM, GE, and some nutrients in corn-soybean meal diets and in DDGS than Yorkshire pigs.

Dehydrated citrus pulp (DCP) contains limiting amount of nitrogen (N) and phosphorus (P), probably due to the high content of fiber components and phytic acid. The use of fibrolytic enzymatic complexes could favor the use of DCP in piglets’ diets. Thus, the objective of this work was to determine the balance of P and N in weaned piglets fed diets with increasing levels of DCP, with or without the addition of exogenous enzymes. Forty castrated male piglets with average initial weight of 7.85 ± 1.64 kg were individually distributed in metabolic cages, in a factorial scheme (2x4): with or without exogenous enzymatic complex (carbohydrases + phytase) X levels of DCP inclusion (0, 3, 6 and 9%) to the diets, with five replicates per treatment and one animal per experimental unit. Diets were formulated based on corn, soybean meal, powdered milk, powdered whey, sugar, soybean oil, amino acids, vitamins, minerals and additives. Experimental diets were provided for 12 d with the initial 7 d being the adaptation period. Ferric oxide (Fe2O3) was added as an indigestible marker on d 7 and 11, respectively. P and N in diets, feces and urine were determined for P and N balance calculation. There was no interaction (P> 0.05) between the addition of enzymes and the levels of DCP. However, there was a reduction (P= 0.067) of P excreted in the feces by the addition of enzymes, as well as a reduction (P= 0.028) of N excreted in the feces. Increasing DCP levels in diets resulted in a linear increase (P= 0.046) of N excreted in feces and a linear reduction (P= 0.038) of N absorbed. The addition of exogenous enzymes (carbohydrases and phytase) in diets for weaned piglets reduces fecal excretion of P and N, while DCP inclusion increases the N excretion in feces.

Three experiments were performed to study the nutritional characteristics of sugar beet pulp (SBP) according to the concentration of vinasse (condensed molasses solubles) added. Eighteen Merino ewes were used to study preference in Exp. 1, and 18 Merino ewes were used in Exp. 2 to study voluntary intake of SBP with different amounts of vinasse inclusion (0, 7, and 13% on a DM basis; SBP0, SBP7, and SPB13, respectively). Sheep showed a marked preference for SBP with vinasse, regardless of the amount of addition, whereas voluntary feed intake was not affected (P > 0.34). Eight ruminally cannulated Merino ewes were used in Exp. 3 to study rumen fermentation of SBP0 and SBP13. Regardless of the diet fed to the animals (SBP0 or SBP13), disappearance rates of DM, NDF, and CP were greater when SBP13, compared with SBP0, was incubated in sacco (P 0.23) in response to vinasse addition. Experiment 4 was designed to study digestibility, solid passage rate, and excretion of purine derivatives from 12 Merino ewes fed SBP0 and SBP13. Digestibility of NDF tended to be greater (P 0.11). Digesta flow kinetics and urinary excretion of purine derivatives were not significantly affected by the presence (SBP13) or absence (SBP0) of vinasse in the diet (P > 0.21). In conclusion, sheep showed a clear preference for SBP with vinasse. However, the lack of significant differences in most of the in vivo variables measured indicates that ewes can be satisfactorily fed with any of the amounts of vinasse inclusion studied.

Eight gilts (29.9 ± 1.7 kg initial BW) were used to evaluate effects of dietary (crude) fiber on N excretion via feces and urine at 2 levels of dietary CP. Pigs were fed 4 dietary treatments according to a double 4 × 4 Latin square. Treatments were low (14%) CP and low (3.25%) (crude) fiber (LPAA), low CP and high (4.46%) fiber (LPAABP), high (18.8%) CP and low fiber (HP), and high CP and high fiber (HPBP). Diets were based on soybean (Glycine max) meal, wheat (Triticum aestivum), and maize (Zea mays) and were supplemented with crystalline AA. High fiber diets contained 15% dried beet (Beta vulgaris) pulp. Pigs were housed in metabolic cages and fed 2 equal meals at 0700 and 1700 h at a daily rate of 90 g/kg BW(0.75). Water was offered ad libitum. Each experimental period consisted of a 6-d adaptation followed by a 4-d collection of feces and urine (bladder catheters). Data were analyzed using ANOVA. Differences between means (P < 0.05) were assessed using Fisher's LSD procedure. The N intake, fecal N excretion and absorption, and N retention increased (P < 0.05) in pigs fed high-CP diets with added fiber (HP vs. HPBR). With added fiber, urinary N excretion (g/d) was reduced (P < 0.02) only for the low-CP diet. Urinary N as a percentage of N intake was reduced (P < 0.01) in both groups fed high-fiber diets irrespective of dietary CP content. Dietary fiber level did not affect DMI. Fecal DM excretion (g/d) was higher (P < 0.02) in pigs fed diets with high CP and high fiber content than in pigs fed diets with high CP and low fiber content. In conclusion, beet pulp fiber added to diets increased fecal N and reduced urinary N and in diets with higher CP content increased overall N retention.

Eight ruminally cannulated steers (average initial weight 196 & 13 kg) were arranged in a replicated 4 x 4 Latin square. Steers had ad libitum access to chopped brome hay (Bromus inermus L. 9.9% CP) and one of four supplements. Supplements were fed to provide 195 g of CP.steer-l.d-l (equalized with soybean meal), and supplemental energy intake was similar among energy supplements. Supplemental treatments were control (CTRL; primarily soybean meal), barley (BAR), beet pulp (PULP), and corn (CORN). Amounts fed were 481, 1,285, 1,335, and 1,289 g of DM.steer-l.d-l for CTRL, BAR, PULP, and CORN, respectively. Individually stanchioned steers were allowed a 13-d adaptation period followed by an 8-d collection period. Chromic oxide was used as the indigestible flow marker. Forage intake was less (P < .lo) for steers fed BAR, PULP, and CORN than for CTRL steers, but total intake (forage + supplement) did not differ among treatments. Total tract DM and OM digestibilities were greater (P < .lo) for PULP- and CORN- than for CTRL- and BAR-supplemented steers. Digestibility of NDF was least (P < .lo) for BAR, intermediate for CORN, and greatest for CTRL and PULP (44.0, 47.2, 50.1, and 52.1%, respectively). Apparent CP digestibility was least ( P < .lo) in BAR- (60.81, greatest in CTRL- (69.71, and intermediate in PULP- and CTRL- (64.0 and 64.4) supplemented steers. Ruminal DM fill was less (P < .lo) in steers fed BAR and PULP than in CTRL steers. No differences ( P < .lo) were noted in DM and NDF rate of in situ degradation. Rate of forage CP in situ degradation was faster ( P < .lo) in CTRL- and PULP- than in CORN- and BAR-supplemented steers. Steers fed BAR and PULP supplements exhibited a lower overall pH response curve (P < .005) than did steers fed CTRL and CORN; this finding corresponded to increased (P < .005) response curves in PULP-fed steers for total VFA, acetate, and propionate compared with other treatments. These data indicate that energy supplementation decreased forage intake, al- tered ruminal fill, shifted VFA patterns, and changed in situ rate of forage CP degradation. Moreover, PULP maintained NDF digestibilities equal to CTRL levels, whereas CORN and BAR did not.

We investigated the effects of dietary factors on the pH and the ammonia emission from slurry of growing-finishing pigs. Sixteen male hybrid pigs (80 to 90 kg BW) were allotted to one of four diets based on barley-wheat, tapioca, barley-tapioca, and sugar beet pulp. Diets were formulated to have similar NE and CP contents and a similar lysine:NE ratio. Diets differed in nonstarch polysaccharide content (NSP) and dietary electrolyte balance (dEB). Urine and feces were daily collected quantitatively in metabolism cages and mixed as a slurry at the end of the collection period. After mixing, the pH and the ammonia emission from the slurry were measured daily in a laboratory setup for 7 d at 20 degrees C. The type of diet affected the pH of the slurry and the ammonia emission (P < .001). The pH of the slurry from pigs fed the sugar beet pulp-based diet was .8 unit lower and ammonia emission was 52 to 53% lower than that of the other three diets. The low dEB and high NPS sugar beet pulp-based diet increased the VFA concentration and reduced the pH and ammonia emission from the slurry. We conclude that dietary NSP and dEB influence the pH and ammonia emission from slurry of growing-finishing pigs.

Summary N a search for a more productive outlet I for the fibrous residues generated during commercial pulp and paper operations, repre­ sentative residues were screened for their potential as feedstuffs for ruminants, In vitro rumen digestibilities of many of the residues ranged from 45 to 60% ; some attained levels as high as 90%. Analytical data for Klason lignin, total carbohydrate, and ash constituents were also obtained. Four typical residues-screen rejects from the sulfite pulping of aspen, unbleached paren­ chyma cell fines from an aspen sulfite tissue mill, unbleached fines from a southern pine kraft mill, and bleached fines from a mixed hardwood southern kraft mill-wereobtained in sufficient quantity for feeding trials with goats, sheep, and steers. The residues were blended with other ration ingredients, and pelleted. In vivo digestibilities for the four residues are estimated to be 58, 52, 47 and 78%, respectively, indicative of substantial utilization of the available carbohydrate con­ stituents. A ration containing 77.4% paren­ chyma cell fines adequately maintained ewes for 2.5 months, and had good acceptability. Steers were fed rations containing 0 and 50% unbleached southern pine kraft pulp fines ad libitum for 58 days. Average daily gain was 0.77 and 0.54 kg, daily feed intake as a percent of body weight was 2.84 and 2.48, and feed/gain ratio was 9.44 and 11.69 for the 0 and 50% pulp rations, respectively. Rumen pH, ammonia, and volatile fatty acid ranged from 6.4 (0 pulp ration) to 6.6 (65% 1

One hundred thirty New Zealand White x California rabbits were used to study the influence of the source of dietary fiber on several digestive criteria. Five diets were formulated to provide 10% crude fiber (CF) on a DM basis. Sixty percent of this dietary fiber was supplied by alfalfa hay, citrus pulp, beet pulp, grape marc, or rice hulls in the diets. Weights of cecal contents, cecal ammonia concentration, and molar proportion of acetic acid in diets including pulps were higher and cecal levels of DM, CP, and molar proportion of butyric acid were lower than those of the alfalfa diet. Cecal ammonia, VFA, and CF concentrations of the grape marc diet were the lowest of all the diets studied; cecal CF level and molar proportion of acetic acid were significantly higher and CP level and molar proportion of butyric acid were lower in rice hull than in alfalfa diets. Diet had no influence on daily soft feces excretion (10 g DM/d), but N contribution of soft feces to N intake was higher in the diet with citrus pulp (18.7%) than in the other diets (12%). Mean retention time (R) was measured using fuchsin-stained feed and was found to be higher (21.3 h) in the rice hull diet and lower (9.3 h) in the grape marc diet than in the other diets. When coprophagy was prevented, R decreased by 0 to 7 h. In conclusion, the use of byproducts to substitute for traditional sources of fiber in rabbit diets influenced the retention time of the digesta in some segments of the gut and thus altered several digestive criteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Previous research identified that a review of the current industry New Zealand lamb survival trait was necessary as its recording accuracy was reliant on farmers notifying their Sheep Improvement Limited bureau of lamb deaths. This paper reports the decision rules and genetic parameters for a new lamb survival trait for the New Zealand sheep industry. These rules define the new lamb survival trait (NEWSUR) using lamb birth fate (BFATE) codes and the presence/absence of lamb weight measurements. Six univariate animal models were tested and used to estimate variance or covariance components and the resulting direct and maternal heritabilities for NEWSUR. The models differed in the way they adjust for the effect of day of birth, the exclusion or inclusion of a litter (dam/year of birth) random effect, and the application or not of a logit transformation of the phenotypes. For both the linear and logistic methods, models including the random effect of litter provided the best fit for NEWSUR according to log-likelihood values. Log-likelihoods for the linear and logistic models cannot be compared; therefore, a cross-validation method was used to assess whether the logit transformation was appropriate by analyzing the predictive ability of the models. The mean square errors were slightly lower for the linear compared with the logistic model, and therefore, the linear model was recommended for industry use. The heritability attributed to direct effects ranged from 2 to 5.5%. A direct heritability of 5.5% resulted from a linear model without litter effect and omitting the effect of day of birth on survival, whereas a direct heritability of 2% resulted from the logistic model fitting a random litter effect. The heritability attributed to maternal genetic effects ranged from 1.9 to 7.7%. A maternal genetic heritability of 7.7% resulted from the logistic model omitting the litter effect, whereas a maternal genetic heritability of 1.9% resulted from the linear model fitting a random litter effect. The addition of the litter random effect substantially decreased the maternal heritabilities in all cases and was recommended for industry use to avoid overestimation of the maternal genetic variance. Sheep Improvement Limited has implemented NEWSUR and the associated genetic evaluation model based on information described in this paper. Industry-wide implementation will enable sheep breeders to produce more accurate genetic evaluations to their commercial clients.

A meta-analysis on the effects of management and animal-based factors on the reproductive efficiency of gestating sows can provide information on single-factor and interaction effects that may not have been detected in individual studies. This study analyzed the effects of such factors on the number of piglets born alive per litter (BA), piglet birth weight (BiW) and weaning weight (WW), and number of piglets born alive per kilogram of sow feed intake during gestation (BA/FI). A total of 51 papers and 7 data sources were identified for the meta-analysis, out of which 23 papers and 5 sets of production data were useable (a total of 121 treatments). The information gathered included the dependent variables as well as information regarding animal, management, and feed characteristics. While a number of factors were individually significant, the multivariate models identified significant effects only of 1) floor type (P=0.003), sow BW at the end of gestation (P=0.002), and housing (stalls vs. loose; P=0.004) on BA; as floor type and housing were confounded, they were included in 2 separate models. The BA was higher on solid (12.1) in comparison to partly slatted (11.4) and fully slatted floors (10.2); 2) sow gestation environment (P=0.017) and gestation feed allowance (P=0.046) on BiW, with BiW of pigs higher for sows kept outdoors rather than indoors (1.75 versus 1.49 kg); 3) parity number (P=0.003) and feed intake during gestation (P=0.017) on WW; in addition there was an interaction between parity number×feed ME and parity number×feed CP content of feed during gestation on WW, with the positive effects of feed ME and CP contents seen during early rather than later parities; and 4) floor type (P=0.019) and feed crude fiber (P=0.003) for BA/FI with a greater number for those kept on solid floors (5.11) versus partially and fully slatted floors (4.07 and 4.05). The meta-analysis confirmed the significant effect of several well-known factors on the efficiency of gestating sows and, importantly, the interactions between these factors. In addition, the effects of some less established factors were noted, such as floor type. The results may contribute towards the improvement of efficiency of gestating sow systems by better understanding of the various factors that influence this.

The objective of this paper was to derive economic weights for performance and survival traits of growing pigs including feed conversion ratio (FCR), daily feed intake (DFI), ADG, postweaning survival of the growing pig (SG), and carcass fat depth at the P2 site (CFD). An independent model was developed for each trait to derive economic values directly based on a typical Australian production system. This flexible approach may be used to customize economic values for different production systems and alternative trait combinations in breeding objectives. Discounted genetic expressions were used as a means of taking into account differences in frequency and timing of expression of traits to obtain economic weights. Economic values for SG were derived based on a cost-saving and a lost-revenue approach. The correct formulation of the economic value of ADG depends on how feed cost is included in the breeding objective. If FCR is defined as a breeding objective trait, then savings in feed costs through earlier slaughter should not be counted in the economic value of ADG. In contrast, if DFI is included in the breeding objective instead of FCR, then feed-cost savings through earlier slaughter need to be attributed to the economic value for ADG, as a benefit from faster ADG. The paper also demonstrates that economic weightings in indexes for FCR can potentially be overestimated by 70% when it is assumed that DFI or FCR records taken from a limited duration test period reflect the corresponding trait over the full lifetime of the growing pig destined for slaughter. Postweaning survival of the growing pig was the most important breeding objective trait of growing pigs. The relative importance of each breeding objective trait in a sire-line index based on the genetic SD of each trait was 44.5, 27.0, 17.4, and 11.1% for SG, FCR, ADG, and CFD, respectively. Further studies to better clarify the extent of genetic variation that exists in SG under nucleus-farm and commercial-farm conditions are warranted, given the high economic importance of this survival trait of growing pigs.

Objectives of this study were to determine the influence of five donor cow diets that differed in source of fiber on true in vitro DM digestibility of eight forages. Test forages included two alfalfa (31.2 and 38.3% NDF), corn silage (50.2% NDF), oat forage (48.2% NDF), perennial rye (62.1% NDF), two reed canarygrasses (55.9 and 68.1% NDF), and timothy (68.2% NDF). Sources of fiber in donor cow diets were alfalfa haylage or alfalfa haylage plus either corn cobs, cottonseed hulls, oat hulls, or soy hulls. In addition, the effect of filtering through sintered glass crucibles or filter paper (two replicates each) was evaluated. There were differences (P.01) among feeds in in vitro DM digestibility, but there were no interactions (P.05) between test forages and either source of fiber in donor diets or filtration method. There was an interaction between source of fiber in the donor diet and method of filtration (P.01). Samples inoculated with ruminal fluid from cows fed diets with oat hulls or soy hulls had lower (P.01) in vitro DM digestibility when filtered on crucibles than on filter paper. Filtration method did not affect (P.05) in vitro DM digestibility of samples inoculated with ruminal fluid from other diets. The in vitro DM digestibility of samples inoculated with ruminal fluid from cows fed alfalfa haylage was less than the in vitro DM digestibility when other inocula were used. The source of fiber in the donor cow diet and filtration method can affect in vitro DM digestibility, but relative ranking of forages was unaffected by these variables.

Macro- and microminerals are required for all physiological processes in beef cattle. When mineral deficiencies occur in pasture-based production systems, a multitude of deficiency symptoms may occur, and most often, these deficiencies result in hidden losses to include reduced production potential, reduced immunity, and reproductive failure. More severe deficiencies will result in specific deficiency symptoms, depending on the specific mineral deficiency. In pasture-based beef operations, specific deficiency symptoms are seldom observed. Forage mineral supply is highly variable and dependent on the forage type, stage of forage growth, and soil fertility. Grazing cattle mineral requirements change throughout the production cycle. With the variability of forage mineral supply and the changing mineral requirements, care must be taken when developing mineral supplementation programs for grazing cattle. The macrominerals function in nerve transmission, bone development, and metabolism and as electrolytes. These are Ca, P, Mg, Na, K, Cl, and S. The microminerals function in various areas of metabolism, immune responsiveness, reproductive efficiency, and many other functions. These minerals are Zn, Cu, Fe, I, Mn, Se, Mo, and Co. Of these macro- and microminerals, those that are important for supplementation to pasture-based cattle include Ca, P, Mg, Na, Cl, Zn, Cu, I, Mn, Se, and Co. However, the amounts to be supplemented will depend on the specific mineral requirements and the forage supply of the minerals. Consequently, the development of free-choice mineral supplementation programs is a moving target. Generally, this entangled mess is sorted by taking one mineral at a time into consideration. However, in doing so, one has to be cognizant of the many interactions that occur when changing intake of just 1 mineral in the supplement with respect to the amount supplied in the base forage. Often times, mineral nutrition problems of one or more minerals are created when trying to correct a deficiency of another mineral. This paper will address specific factors that are important to consider when developing and delivering mineral supplementation programs in pasture-based production systems in the Southeastern United States.

Since the 1990s, the impact of late gestational nutrition and management on lactation and reproduction has become the focus of dairy management. Transition cow management has been credited with having greater influence on herd performance as compared to previous focus on lactation nutrition. Several seminal papers published in 1990s and early 2000s directed management practices of dry cows, rightly or wrongly, toward critical factors impacting calving and lactation. Dairy cow gestational protein requirements cited a 1956 study on Red Danish cows until Bell (1995) characterized the modern Holstein fetus’ chemical composition over the last 70 days of gestation. Recognized health effects of “fat cow syndrome”, similarly described for pigs, focuses late pregnant dairy cow management on body condition management starting in late lactation. Optimum condition was emphasized, recognizing negative impacts of excessive limited BC on lactation and reproduction. Maximizing dry matter intake was a nutritional goal for preventing energy-based metabolic challenges, until research indicated excessive energy during early, non-lactating period was more critical to managing postpartum metabolic derangements than the weeks prior to calving; which is like controlling energy intake of sows. Delivery of amino acids, estimated by metabolizable protein intake, has recently earned focus of research, relative to immune function, metabolic stability and reproductive success during early lactation. Identifying amino acids as critical fetal metabolic fuel, and consequences of excessive maternal protein mobilization, has become a focal point of swine and dairy transition nutrition. Although management of the transition cow has been greatly refined through nutritional research, improved cow performance has not yet been realized in the field. Recognition of the interplay between nutrition, environment and management relative to enhancing cow behavior has provided insight to the challenges of managing the transition cow. Metabolic, environmental and management challenges facing the physiologic transition from pregnancy into lactation occur in all production species. Although cows and sows procure essential nutrients by different digestive modes, cross-species applications can provide new or reinforcing perspectives on collective management approaches.

The objective of this paper is to present a systematic review and meta-analysis of research efforts aimed at recovering cattle production losses attributed to toxic endophyte-infected [ (Morgan-Jones & Gams.) Glenn, Bacon, & Hanlin comb. Nov.] tall fescue [ (Schreb.) Darbysh.]. The strategies presented include those 1) applied with forage systems, 2) based on pharmacological compounds and functional foods, and 3) based on supplemental dietary nutrients. Cattle BW gain and DM intake was the dependent response evaluated. Among the forage systems reviewed, studies with nontoxic, endophyte-infected tall fescue as a total replacement forage system demonstrated the greatest improvement in per-hectare (152 ± 27.5 kg/ha) and per-animal (0.29 ± 0.03 kg/d) BW gain. Studies with interseeded legumes have exhibited a small and highly variable BW gain effect size per hectare (52 ± 24.1 kg/ha) and per animal (0.11 ± 0.03 kg/d). The legume response was seasonal, with summer exhibiting the greatest benefit. Studies with chemicals that suppress plant growth demonstrated BW gain responses (0.17 ± 0.06 kg/d) equal to or greater than the response observed with legume studies. Cattle grazing toxic tall fescue responded well to anthelmentics, antimicrobial feed additives, and steroid implants, and the use of these technologies may additively help recover production losses. As a group, functional foods have not improved BW gain ( = 0.85). Studies with cattle supplemented with highly digestible fiber supplements observed a 0.15 kg greater BW gain compared with studies using starch- and sugar-based supplements ( < 0.05). Weight gain was positively impacted by the level of supplementation (0.06 kg/DM intake as percent BW). Supplement feed conversion was estimated at 6:1 for the highly digestible fiber supplements compared with 11:1 for starch-based supplements. Tall fescue forage DM intake was predicted to maximize at a supplemental feeding rate of 0.24% BW with a breakpoint at 0.5% BW, and total maximum DM intake (forage plus supplement) occurred at 2.7% BW when supplemental feeding approached 0.9% BW. Results from this meta-analysis should be useful for 1) establishing and comparing measured responses to theoretical improvements in BW gain when additive strategies are considered, 2) research planning, and 3) producer education.

The selection of animals for improved performance affects the profitability of pig fattening and has environmental consequences. The goal of this paper was to examine how changes in genetic and market parameters impact the biophysical (feeding patterns, timing of slaughter, nitrogen excretion) and economic (return per pig space unit) results describing pig fattening in a Finnish farm. The analysis can be viewed as focusing on terminal line breeding goals. An integrated model using recursive stochastic dynamic programming and a biological pig growth model was used to estimate biophysical results and economic values. Combining these models allowed us to provide more accurate estimates for the value of genetic improvement and, thus, provide better feedback to animal breeding programs than the traditional approach, which is based on fixed management patterns. Besides the benchmark scenario, the results were simulated for 5 other scenarios. In each scenario, genotype was improved regarding daily growth potential, carcass lean meat content, or the parameters of the Gompertz growth curve (maturing rate [], adult weight of protein [α], and adult weight of lipid mass []). The change in each parameter was equal to approximately 1 SD genetic improvement (ceteris paribus). Increasing , , daily growth potential, or carcass lean meat content increased the return on pig space unit by €12.60, €7.60, €4.10, or €2.90 per year, respectively, whereas an increase in decreased the return by €3.10. The genetic improvement in and resulted in the highest decrease in nitrogen excretion calculated in total or per kilogram of carcass gain but only under the optimal feeding pattern. Simulated changes in the Gompertz growth function parameters imply greater changes in ADG and lean meat content than changes in scenarios focusing on improving ADG and lean meat content directly. The economic value of genetic improvements as well as the quantity of nitrogen excreted during the fattening period largely depends on feeding. Improved genotypes can require changes in pig management pattern. Estimating the influence of the genotype on the nitrogen excretion without considering changes in the management pattern can result in flawed conclusions. To improve overall economic performance and to decrease the environmental footprint of fattening pig production, the pig producer can adjust the herd management pattern according to the pigs' genetics.

A single-step method allows genetic evaluation using information of phenotypes, pedigree, and markers from genotyped and nongenotyped individuals simultaneously. This paper compared genomic predictions obtained from a single-step BLUP (SSBLUP) method, a genomic BLUP (GBLUP) method, a selection index blending (SELIND) method, and a traditional pedigree-based method (BLUP) for total number of piglets born (TNB), litter size at d 5 after birth (LS5), and mortality rate before d 5 (Mort; including stillbirth) in Danish Landrace and Yorkshire pigs. Data sets of 778,095 litters from 309,362 Landrace sows and 472,001 litters from 190,760 Yorkshire sows were used for the analysis. There were 332,795 Landrace and 207,255 Yorkshire animals in the pedigree data, among which 3,445 Landrace pigs (1,366 boars and 2,079 sows) and 3,372 Yorkshire pigs (1,241 boars and 2,131 sows) were genotyped with the Illumina PorcineSNP60 BeadChip. The results showed that the 3 methods with marker information (SSBLUP, GBLUP, and SELIND) produced more accurate predictions for genotyped animals than the pedigree-based method. For genotyped animals, the average of reliabilities for all traits in both breeds using traditional BLUP was 0.091, which increased to 0.171 w+hen using GBLUP and to 0.179 when using SELIND and further increased to 0.209 when using SSBLUP. Furthermore, the average reliability of EBV for nongenotyped animals was increased from 0.091 for traditional BLUP to 0.105 for the SSBLUP. The results indicate that the SSBLUP is a good approach to practical genomic prediction of litter size and piglet mortality in Danish Landrace and Yorkshire populations.

This volume represents the span of invited papers presented at the Eighth International Workshop on the Biology of Lactation in Farm Animals (BOLFA) held in Pirassununga, Brazil, August 21 to 23, 2006. That meeting was the first BOLFA workshop not held as a companion to a European Association for Animal Production (EAAP) or American Society of Animal Science (ASAS) meeting, and the first outside of North America or Europe. Despite these venue departures from the norm, the workshop format of interactive discussion on topics related to milk production in farm animal species was unchanged. This volume begins with a paper from Antonella Baldi’s group (Baldi et al., 2008) that provides a historical perspective of previous BOLFA workshops with an emphasis on nutritional factors that influence mammary function. It sets the stage for the later papers that consider aspects of milking management and mastitis treatment to improve milk yield in farm animal species. The next series of contributions focus on environmental and management influences on mammary function. Dahl (2008) summarizes recent developments in the study of photoperiod exposure during the dry period and develops a hypothesis that prolactin-mediated events influence mammary cell turnover and metabolic gene expression in the liver. These findings lead to a discussion of similarities between photoperiodic and thermal influences on prolactin-related responses, and the potential for a common pathway for environmental effects. Without competent milk ejection, lactation fails. More thorough understanding of what stressors lead to disruptions in the milk ejection reflex, or inhibit it completely, will allow for the development of new meth

Improving the traits that underlie meat quality is a major challenge in the beef industry. The objective of this paper was to detect QTL linked to sensory meat quality traits in 3 French beef cattle breeds. We genotyped 1,059, 1,219, and 947 young bulls and their sires belonging to the Charolais, Limousin, and Blonde d'Aquitaine breeds, respectively, using the Illumina BovineSNP50 BeadChip (Illumina Inc., San Diego, CA). After estimating relevant genetic parameters using VCE software, we performed a linkage disequilibrium and linkage analysis on 4 meat traits: intramuscular fat content, muscle lightness, shear force, and tenderness score. Heritability coefficients largely ranged between 0.10 and 0.24; however, they reached a maximum of 0.44 and 0.50 for intramuscular fat content and tenderness score, respectively, in the Charolais breed. The 2 meat texture traits, shear force and tenderness score, were strongly genetically correlated (-0.91 in the Charolais and Limousin breed and -0.86 in the Blonde d'Aquitaine breed), indicating that they are 2 different measures of approximately the same trait. The genetic correlation between tenderness and intramuscular fat content differed across breeds. Using a significance threshold of 5 × 10(-4) for QTL detection, we found more than 200 significant positions across the 29 autosomal chromosomes for the 4 traits in the Charolais and Blonde d'Aquitaine breeds; in contrast, there were only 78 significant positions in the Limousin breed. Few QTL were common across breeds. We detected QTL for intramuscular fat content located near the myostatin gene in the Charolais and Blonde d'Aquitaine breeds. No mutation in this gene has been reported for the Blonde d'Aquitaine breed; therefore, it suggests that an unknown mutation could be segregating in this breed. We confirmed that, in certain breeds, markers in the calpastatin and calpain 1 gene regions affect tenderness. We also found new QTL as several QTL on chromosome 3 that are significantly associated with meat tenderness in the Blonde d'Aquitaine breed. Overall, these results greatly contribute to the goal of building a panel of markers that can be used to select animals of high meat quality.

This paper reports genetic parameters for lamb survival and mortality traits on sheep farms in New Zealand. Lamb survival and mortality records were obtained from 38 flocks (103,357 lambs) from 5 yr of lambing data (2007 to 2011) and include many breeds and their crosses (predominantly Romney, Perendale, Coopworth, and Texel). A number of models were tested, all including environmental weather effects and investigating the random environmental effect of dam and litter (dam/year) as well as logit transformation for binary traits. Total heritability (direct + maternal) estimates were low for lamb viability at birth (0.01), lamb death risk to dystocia (0.01), and lamb death risk to starvation exposure (0.01) from birth to 3 d of age in an analysis accounting for direct and maternal genetic effects and the maternal environmental effects. Lamb survival heritabilities reported are very low (total heritabilities range from 0.02 to 0.06). The total heritabilities for the lamb death risk traits are lower than reported estimates of survival to 3 d of age or to weaning suggesting selection for the postmortem traits are not warranted at this time within these flocks. The total heritability for lamb birth weight was moderate (0.38) and the genetic correlations with the lamb death risk traits suggested that directional selection on lamb birth weight would have an effect on survival, although it is likely to have a nonlinear effect and therefore an optimum birth weight at which survival is maximized. This study has also shown that the total heritabilities may be overestimated when not accounting for maternal genetic and environment effects and in particular not accounting for the random environmental effect of litter (dam/year).

The efficiency of producing salable products in the pork industry is largely determined by costs associated with feed and by the amount and quality of lean meat produced. The objectives of this paper were 1) to explore heritability and genetic correlations for growth, feed efficiency, and real-time ultrasound traits using both pedigree and marker information and 2) to assess accuracy of genomic prediction for those traits using Bayes A prediction models in a Duroc terminal sire population. Body weight at birth (BW at birth) and weaning (BW at weaning) and real-time ultrasound traits, including back fat thickness (BF), muscle depth (MD), and intramuscular fat content (IMF), were collected on the basis of farm protocol. Individual feed intake and serial BW records of 1,563 boars obtained from feed intake recording equipment (FIRE; Osborne Industries Inc., Osborne, KS) were edited to obtain growth, feed intake, and feed efficiency traits, including ADG, ADFI, feed conversion ratio (FCR), and residual feed intake (RFI). Correspondingly, 1,047 boars were genotyped using the Illumina PorcineSNP60 BeadChip. The remaining 516 boars, as an independent sample, were genotyped with a low-density GGP-Porcine BeadChip and imputed to 60K. Magnitudes of heritability from pedigree analysis were moderate for growth, feed intake, and ultrasound traits (ranging from 0.44 ± 0.11 for ADG to 0.58 ± 0.09 for BF); heritability estimates were 0.32 ± 0.09 for FCR but only 0.10 ± 0.05 for RFI. Comparatively, heritability estimates using marker information by Bayes A models were about half of those from pedigree analysis, suggesting "missing heritability." Moderate positive genetic correlations between growth and feed intake (0.32 ± 0.05) and back fat (0.22 ± 0.04), as well as negative genetic correlations between growth and feed efficiency traits (-0.21 ± 0.08, -0.05 ± 0.07), indicate selection solely on growth traits may lead to an undesirable increase in feed intake, back fat, and reduced feed efficiency. Genetic correlations among growth, feed intake, and FCR assessed by a multiple-trait Bayes A model resulted in increased genetic correlation between ADG and ADFI, a negative correlation between ADFI and FCR, and a positive correlation between ADG and FCR. Accuracies of genomic prediction for the traits investigated, ranging from 9.4% for RFI to 36.5% for BF, were reported that might provide new insight into pig breeding and future selection programs using genomic information.

Genetic drift (GD) randomly impacts small breeds and imported populations. Therefore, it can impact policies that affect conservation of animal genetic resources. This paper evaluates GD for a population of Meishan pigs imported into the United States and explores the ramifications of GD on access and benefit sharing of genetic resources under the Nagoya Protocol (NP) of the United Nations' Convention on Biological Diversity. The NP was motivated by concerns about fair and equitable benefit sharing of genetic resources across life forms. In this experiment, 35 microsatellite markers were used to quantify the level of GD that occurred between Meishan pigs (Meishan-China; n = 22) imported into the United States in the late 1980s and contemporary Meishan (Meishan-US; n = 42), which have been randomly bred since importation. The Meishan-US consisted of 2 subpopulations (Meishan-MARC and Meishan-ISU). Five other breeds were also included in the analysis to serve as reference populations: Fengjing and Minzhu, which were imported with Meishan-China, and Duroc, Berkshire, and Yorkshire from the United States. Mean shift in allele frequency was 0.11 (SE = 0.019) due to GD for Meishan-US vs. Meishan-China with some loci having changed allele frequencies by greater than 0.20. Principle coordinate analysis confirmed divergence among the Meishan populations. Model-based clustering tended to place the U.S. and Chinese breeds into 2 distinct clusters, likely due to differences in allele frequencies between U.S. and Chinese breeds. Contemporary Meishan-US has become differentiated from the original imported animals due to GD. Attributing future performance of Meishan-US to Meishan-China, as set forth by NP, is problematic due to GD. As an imported breed becomes established there will be an increasing number of breeders who may have different selection goals and private treaty contracts will govern the exchange of stock between them. Therefore, considering biological phenomena and social dynamics simultaneously draws into question whether a rigorous access and benefit sharing protocol as envisioned in the NP will be operational.

A modeling study based on a dataset from a large-scale grazing study was used to identify the potential impact of grazing behavior and performance of diverse cow genotypes on predicted methane (CH 4 ) emissions. Lactating cows grazing extensive seminatu- ral grassland and heath vegetation were monitored with Global Positioning System collars and activity sensors. The diet selected by cows of 3 different genotypes, Aber- deen Angus cross Limousin (AxL), Charolais (CHA), and Luing (LUI), was simulated by matching their locations during active periods with hill vegetation maps. Mea- sured performance and activity were used to predict ener- gy requirements, DMI, and CH 4 output. The cumulative effect of actual performance, diet selection, and actual physical activity on potential CH 4 output and yield was estimated. Sensitivity analyses were performed for the digestibility of intake, energy cost of activity, proportion of milk consumed by calves, and reproductive efficien- cy. Although with a better performance (P < 0.05), LUI required less total energy than the other genotypes (P < 0.001) as the other 2 spent more ener gy for maintenance (P < 0.001) and activity (P < 0.001). By selecting a better quality diet (P < 0.03), estimated CH 4 of CHA cow-calf pairs was lower than AxL (P = 0.001) and slightly lower than LUI (P = 0.08). Energy lost as CH 4 was 0.17 and 0.58% lower for LUI than AxL and CHA (P < 0.002). This study suggests for the first time that measured activ- ity has a major impact on estimated CH 4 outputs. A 15% difference of the cow-calf pair CH 4 was estimated when using different coefficients to convert actual activity into energy. Predicted CH 4 was highly sensitive to small changes in diet quality, suggesting the relative importance of diet selection on heterogeneous rangelands. Extend- ing these results to a farm systems scale, CH 4 outputs were also highly sensitive to reductions in weaning rates, illustrating the impact on CH 4 at the farm-system level of using poorly adapted genotypes on habitats where their performances may be compromised. This paper demon- strates that variations in grazing behavior and grazing choice have a potentially large impact on CH 4 emissions, illustrating the importance of including these factors in calculating realistic national and global estimates.

Mixing of unfamiliar pigs is a standard management procedure in commercial pig production and is often associated with a period of intense and physically damaging aggression. Aggression is considered a problem for animal welfare and production. The objective of the present paper was to investigate the genetic background of aggressive behavior traits at mixing of unfamiliar gilts under 2 different housing conditions. Therefore, a total of 543 purebred Pietrain gilts, from 2 nucleus farms (farm A: n = 302; farm B: n = 241) of 1 breeding company, were tested at an average age of 214 d (SD 12.2 d) for aggressive behavior by 1 observer. Observations included the frequencies of aggressive attack and reciprocal fighting during mixing with unfamiliar gilts. On farm A 41% of the gilts were purebred Pietrains, whereas 59% were purebred Landrace or Duroc gilts. On the farm B 42% of the gilts were purebred Pietrains, and 58% purebred Large White gilts. The average size of the newly mixed groups of gilts was 28 animals on farm A and 18 animals on farm B. The Pietrain gilts from the 2 herds were genetically closely linked. They were the offspring of 96 sires, with 64% of these sires having tested progeny in both farms. There were clear differences in the housing of the animals between the 2 farms. The test pen on farm A had a solid concrete floor littered with wooden shavings and was equipped with a dry feeder. On farm B there was a partly slatted floor, and the gilts were fed by an electronic sow feeder. Mean space allowance was 2.6 m(2)/gilt on farm A and 3.9 m(2)/gilt on farm B. Although large interindividual differences existed, gilts from farm B performed numerically more aggressive attack (mean 1.12, SD 1.42 vs. mean 0.71, SD 1.20) and reciprocal fighting (mean 0.78, SD 0.98 vs. mean 0.44, SD 0.82) when compared with gilts from farm A. The heritabilities and additive genetic variances for behavioral traits were estimated with a linear animal model and were on a low level in farm A (h(2) = 0.11, SE = 0.07, and σ(2)a = 0.12 for aggressive attack and h(2) = 0.04, SE = 0.07, and σ(2)a = 0.02 for reciprocal fighting) and on a moderate level in farm B (h(2) = 0.29, SE = 0.13, and σ(2)a = 0.44 for aggressive attack and h(2) = 0.33, SE = 0.12, and σ(2)a = 0.27 for reciprocal fighting). For both aggressive attack and reciprocal fighting, genetic correlation of the same trait between farm A and farm B was 1.0. Therefore, aggressive behavior does not seem to be influenced by genotype × environment interactions. Under these circumstances aggressions in group housing can be reduced by genetic selection against aggressive behavior. Therewith, the welfare and health of sows will ultimately increase.

This paper reviews results of studies on effects of fetal programming and maternal nutrition during pregnancy on growth, efficiency, carcass, muscle, and meat quality characteristics of cattle. It includes results from our Australian Beef Cooperative Research Centre studies on factors such as chronic severe nutritional restriction from approximately d 80 of pregnancy to parturition and/or throughout lactation used to create early-life growth differences in the offspring of cows within pasture-based systems and the effect of these treatments on production characteristics to 30 mo of age. Fetal programming and related maternal effects are most pronounced and explain substantial amounts of variation for growth-related production characteristics such as BW, feed intake, carcass weight, muscle weights, meat yield, and fat and bone weights at any given age but are less evident when assessed at the same BW and carcass weight. Some effects of maternal and early-life factors in our studies were evident for efficiency traits but fewer affected beef quality characteristics at 30 mo of age, explaining only small amounts of variation in these traits. It is difficult to uncouple maternal nutritional effects specific to prenatal life from those that carry over to the postnatal period until weaning, particularly the effects of maternal nutrition during pregnancy on subsequent lactational performance. Hence, experimental design considerations for studying fetal programming effects on offspring during later life are discussed in relation to minimizing or removing prenatal and postnatal confounding effects. The relative contribution of fetal programming to the profitability of beef production systems is also briefly discussed. In this regard, the importance of health and survival of cows and calves, the capacity of cows to rebreed in a timely manner, and the efficiency with which feed and other resources are used cannot be overemphasized in relation to economics, welfare, and the environment.

The hypothesis tested in this paper is that double-muscled (DBM) and conventional cattle, considerably differing in body composition, have similar NE requirements when: a) NE(m) is scaled as a function of current (P(i)) and adult (P(m)) protein mass; and b) ME for gain (ME(g)) is estimated from protein (Pr) and lipid (Lr) retention and their partial ME use efficiencies, the k(p) and k(l) values, respectively. First, 2 databases were examined: 1 was developed combining well known literature information from comparative slaughter trials conducted on British beef steers; the other was based on a trial conducted using extremely lean DBM Piemontese bulls. From the first database, NE(m) was calculated to be 1.625 × P(i) ÷ P(m) × P(m)(0.73) (MJ/kg(0.73)). From the second database, the daily ME(g) was determined as 22.8 MJ × Pr ÷ k(p) + 38.74 MJ × Lr ÷ k(l), assuming (from prior reports) that k(p) = 0.20 and k(l) = 0.75. Thereafter, ME(m) was defined as ME intake minus ME(g), and, hence, NE(m) was predicted as 1.625 × P(i) ÷ P(m) × P(m)(0.73) (where 1.625 was the value obtained from the first dataset). The resulting k(m) (NE(m)/ME(m)) averaged 0.67. This k(m) value did not differ from that (0.65; P = 0.12) predicted by Garrett's equation, which uses dietary ME content as the only predictive variable. Second, the procedure was tested for the ability to detect effects on k(m) caused by increasing BW and dietary factors not estimable from the dietary ME content only. Data were gathered from a trial involving 48 DBM Piemontese bulls divided into 4 groups fed 1 of 4 diets differing in CP content (145 or 108 g/kg DM), with or without addition of 80 g/d of rumen-protected CLA (rpCLA). Bulls were examined at 3 consecutive periods of growth, corresponding to 365, 512 and 631 kg of average BW. All energy balance items were influenced by increasing BW, except k(m) (P = 0.61), in agreement with the expectation that NE(m) requirement depends on the degree of maturity (P(i)/P(m)) and the P(m)(0.73) of an animal, whereas k(m) reflects characteristics of the feed provided. The k(m) value was also influenced by the CP × rpCLA interaction (P = 0.013). We conclude that DBM and British beef steers have similar NE requirements when these are scaled as a function of P(i) and P(m), and gain composition, considering Pr, k(p), Lr and k(l). The proposed procedure will be useful to predict the energy requirements and feed use in cattle of different types that vary in BW, provided that body and gain compositions are known or accurately predicted.

Monensin is a common feed additive used in various countries, where 1 of the associated benefits for use in beef cattle is improved efficiency of energy metabolism by the rumen bacteria, the animal, or both. Modeling fermentation-altering supplements is of interest, and thus, it is the purpose of this paper to quantify the change in VFA profile caused by monensin dose in high-grain-fed beef cattle. The developmental database used for meta-analysis included 58 treatment means from 16 studies from the published literature, and the proportional change in molar acetate, propionate, and butyrate (mol/100 mol) as well as total VFA (mM) with monensin feeding dose (mg/kg DM, concentration in the feed) was evaluated using the MIXED procedure (SAS Inst. Inc., Cary, NC) with the study treated as a random effect. The mean monensin dose in the literature database was 30.9 ± 3.70 mg/kg DM and ranged from 0.0 to 88.0 mg/kg DM. Mean DMI was 7.8 ± 0.26 kg DM/d, mean concentrate proportion of the diet was 0.87 ± 0.01, and mean treatment period was 42 ± 5.6 d. Results produced the following equations: proportional change in acetate (mol/100 mol) = -0.0634 (± 0.0323) × monensin (mg/kg DM)/100 (P = 0.068), proportional change in propionate (mol/100 mol) = 0.260 (± 0.0735) × monensin (mg/kg DM)/100 (P = 0.003), and proportional change in butyrate (mol/100 mol) = -0.335 (± 0.0916) × monensin (mg/kg DM)/100 (P = 0.002). The change in total VFA was not significantly related to monensin dose (P = 0.93). The results presented here indicate that the shift in VFA profile may be dose dependent, with increasing propionate and decreasing acetate and butyrate proportions (mol/100 mol). These equations could be applied within mechanistic models of rumen fermentation to represent the effect of monensin dose on the VFA profile in high-grain-fed beef cattle.

Inflammation caused by bovine respiratory disease (BRD) continues to be one of the greatest challenges facing beef cattle producers and feedlot managers. Inflammation decreases DMI, ADG, and G:F in feedlot calves, decreasing growth rate and increasing days on feed, which results in economic losses during the feeding period. During the past decade, marketing of feedlot animals has changed from selling cattle on a live basis to a grid-based marketing system. When cattle are marketed on a live basis, the economic effects of BRD stop at increased health cost and decreased feedlot performance, carcass weight, and death loss. However, when cattle are marketed in a grid-based system, inflammation has the potential to also affect carcass cutability and quality. The effects of inflammation on feedlot cattle in regards to performance are well understood; however, specific effects on cattle growth and ultimately carcass merit are not as well described. Recent studies in feedlot cattle have indicated that the incidence of BRD decreases both HCW and marbling; however, mechanisms are not understood. Research in other species has demonstrated that during the acute phase response, pro-inflammatory cytokines promote skeletal muscle catabolism to supply AA and energy substrates for immune tissues. Further, during this early immune response, the liver changes its metabolic priorities to the production of acute phase proteins for use in host defense. Together these dramatic shifts in systemic metabolism may explain the detrimental effects on performance and carcass traits commonly associated with BRD in feedlot calves. Moreover, recent studies relative to human health have revealed complex multilevel interactions between the metabolic and immune systems, and highlighted inflammation as being a significant contributor to major metabolic diseases. The objective of this paper is to review data to help explain the economical and physiological effects of inflammation on cattle growth and carcass merit.

This paper compares energy use for different pig production systems in Iowa, a leader in US swine production. Pig production systems include not only the growth and performance of the pigs, but also the supporting infrastructure of pig production. This supporting infrastructure includes swine housing, facility management, feedstuff provision, swine diets, and manure management. Six different facility type × diet formulation × cropping sequence scenarios were modeled and compared. The baseline system examined produces 15,600 pigs annually using confinement facilities and a corn-soybean cropping sequence. Diet formulations for the baseline system were corn-soybean meal diets that included the synthetic AA l-lysine and exogenous phytase. The baseline system represents the majority of current US pork production in the Upper Midwest, where most US swine are produced. This system was found to require 744.6 MJ per 136-kg market pig. An alternative system that uses bedded hoop barns for grow-finish pigs and gestating sows would require 3% less (720.8 MJ) energy per 136-kg market pig. When swine production systems were assessed, diet type and feed ingredient processing were the major influences on energy use, accounting for 61 and 79% of total energy in conventional and hoop barn-based systems, respectively. Improving feed efficiency and better matching the diet formulation with the thermal environment and genetic potential are thus key aspects of reducing energy use by pig production, particularly in a hoop barn-based system. The most energy-intensive aspect of provisioning pig feed is the production of synthetic N for crop production; thus, effectively recycling manure nutrients to cropland is another important avenue for future research. Almost 25% of energy use by a conventional farrow-to-finish pig production system is attributable to operation of the swine buildings. Developing strategies to minimize energy use for heating and ventilation of swine buildings while maintaining pig comfort and performance is a third critical area for future research. The hoop barn-based alternative uses 64% less energy to operate buildings but requires bedding and 2.4% more feed. Current Iowa pig production systems use energy differently but result in similar total energy use. Compared with 1975, current farrow-to-finish systems in Iowa require 80% less energy to produce live market pigs.

The aim of this work was to evaluate the correlated responses on survival rates after 10 gen- erations of selection for ovulation rate (OR). Selection was based on the phenotypic value of ovulation rate estimated at d 12 of second gestation by laparoscopy. Traits recorded were litter size (LS), estimated as total number of rabbits born per litter in up to 5 parities; OR, estimated as the number of corpora lutea in both ovaries; the number of implanted embryos (IE), esti- mated as the number of implantation sites; the number of right and left IE (RIE and LIE); ovulatory difference (OD), defined as the difference between the right and the left OR, expressed as an absolute value; implanta- tory difference (ID), defined as the difference between RIE and LIE, expressed as an absolute value; embryonic survival (ES), calculated as IE/OR; fetal survival (FS), calculated as LS/IE; prenatal survival (PS), calculated as LS/OR. A total of 1,081 records were used to analyze ES, and 770 were used to analyze FS and PS. The num- ber of records used to analyze the other traits ranged from 1,079 for ID to 3,031 for LS. Data were analyzed using Bayesian methodology. Genetic parameters of OR, OD, and LS were estimated in a previous paper. Estimated heritabilities of IE, ID, ES, FS, and PS were 0.11, 0.03, 0.09, 0.24, and 0.14, respectively. Estimated repeatabilities of IE, ID, and ES were 0.22, 0.12, and 0.20. Estimated phenotypic correlations of OR with ES, FS, and PS were −0.07, −0.26, and −0.28, respectively. Their estimated genetic correlations with FS and PS were negative (probability of being negative 1.00 and 0.98, respectively). Nothing can be said about the sign of the genetic correlation between OR and ES. Ovu- lation rate was phenotypically uncorrelated with ID. Their estimated genetic correlation was positive (prob- ability of being positive 0.91). The genetic correlation of ID with PS and LS was not accurately estimated. Phenotypic and genetic correlations between LS and survival rates were positive (probability of being posi- tive 1.00). In 10 generations of selection, FS decreased around 1% per generation. No correlated response in ES was observed. In summary, the decrease in FS in rabbits selected for OR seemed to be responsible for the lack of correlated response observed in LS.

Environmental effects of excess P from manure and the soaring price of phosphates are major issues in pig production. To optimize P utilization, it is crucial to improve our capacity to predict the amount of P absorbed, while taking into account the main factors of variation. Mathematical modeling can represent the complexity of the processes and interactions in determining the digestive utilization of P in growing pigs. This paper describes and evaluates a model developed to simulate the fate of the dietary forms of P in the digestive tract of growing pigs, with particular emphasis on the effect of dietary Ca and exogenous phytase on P digestive utilization. The model consists of 3 compartments associated with specific anatomical sections: stomach, proximal small intestine, and distal small intestine. The main metabolic processes occurring in these sections are, respectively, P solubilization/insolubilization and phytate P hydrolysis, and P absorption and P insolubilization. Model parameters governing these flows were derived from in vitro and in vivo literature data. The sensitivity analysis revealed that the model was stable within a large range of model parameter values (±1.5 SD). The model was able to predict the efficacy of Aspergillus niger microbial phytase in accordance with literature values, as well as the decreased efficacy of plant phytase compared with microbial phytase. The prediction capabilities of the model were assessed by comparing actual and simulated P and Ca apparent total-tract digestibility (ATTD) based on published pig data not used for model development. Prediction of P digestibility across 66 experiments and 281 observations was adequate [P ATTD observed = 0.24 (SE, 0.943) + 0.98 (SE, 0.0196) × P ATTD predicted; R(2), 0.90; disturbance error (ED), 96.5%], whereas prediction of Ca digestibility across 47 experiments and 193 observations was less accurate (Ca ATTD observed = 11.1 + 0.75 × Ca ATTD predicted; R(2), 0.78; ED, 20.4%). A lack of agreement between experimental and simulated Ca digestibility was found. This model is, therefore, useful in evaluating P digestibility for different feedstuffs and feeding strategies. It can also be used to provide insight for improving dietary P utilization, especially from plant sources, by quantifying the effect of the mean sources of variation affecting P utilization.

Recent advances in on-farm technology now provide us with multiple time-series of reliably measured indicators of animal performance and status at the level of the individual. This paper presents a smoothing approach for extracting biologically meaningful features from such time series using bovine milk yield data as an example. The main goal of this study was to illustrate how the method can be used to detect production deviations, extract quantifiable features of the deviation profiles, and thus provide means to examine hypotheses concerning the nature of the deviations. The effectiveness of the method was assessed with complete lactation curves from 47 Holstein cows. Within their lactations, the cows were each subjected to 1 nutritional challenge for a period of 4 d (their standard diet: a maize silage-based total mixed ration was diluted with 60% wheat straw), which provoked a decline in the milk yield in all cows. The challenge was imposed between the same calendar days for all cows. Thus, the cows were at different stages of lactation: early (n = 14), mid (n = 15), and late (n = 18). Each milk-yield curve was decomposed into components that capture the short-term deviations of the cow such as the response to the nutritional challenge and describe the phenotypic potential yield function of that cow throughout its lactation. The difference between the 2 components gives a measure of the milk loss. In all, 480 deviations were detected from the complete lactations of 47 cows. The milk loss provoked by the feeding challenge (n = 47) was significantly related to the milk yield immediately before the challenge (r = 0.86, P 0.1) to the relationship between the ratio (rate of recovery/milk loss) and days from calving, indicating that the force of recovery was unaffected by stage of lactation. These results suggest that differential smoothing can be a useful tool for quantifying biological disturbances in animal performance and for extracting features that relate to the potential and robustness of an animal.

Recent data suggest morbidity and mortality are increasing in feedlot cattle, primarily due to bovine respiratory disease. It is well documented that disease challenges in beef cattle result in reduced gain, efficiency and HCW in cattle fed to the same DOF. Typically, diseased animals produce carcasses with less desirable quality grades due to reduced marbling scores. More recent data suggest that although diseased animals can be fed to similar fat-thickness endpoints with added DOF, carcass weights and marbling scores are still reduced compared to non-treated contemporaries. Of note, non-treated animals with lung lesions also showed marked reductions in performance, indicating subclinical disease. While the bovine immune response to infectious disease challenge is complex, the acute inflammatory response typically results in the production of acute phase proteins and pro-inflammatory cytokines from the liver. New data suggest that respiratory disease in cattle, as indicated by lung palpation at slaughter, could be related to the presence of 1 or more liver abscesses. Disease increases the animal’s maintenance energy requirements, resulting in less energy available for growth, increased production costs and lower gross revenue. Today, the majority of fed cattle are marketed on a carcass basis (grid or dressed), with HCW accounting for over 80% of the variation in gross revenue from individual animals. These economic factors make disease, and more specifically bovine respiratory disease, a costly challenge for beef production. The objective of this paper is to review the impacts of disease on growth and carcass characteristics, evaluate a large population database to evaluate trends in commercial production, and highlight potential relationships between other diseases experienced in feedlot beef production.