bluuebunny/crossref_metadata_2025 huggingface dataset:
EVIDENCE OF A ROLE FOR GLUCAGON IN REGULATING GLUCOSE AND β-HYDROXYBUTYRATE METABOLISM IN SHEEP
Authors: BROCKMAN RONALD P. , JOHNSON MARILYN R.
Published: March 2010

To evaluate the effect of glucagon on glucose and β-hydroxybutyrate metabolism, glucagon deficiency was induced by infusion of somatostatin. Glucose production rate and glucose and β-hydroxybutyrate concentrations were determined before, during and after somatostatin infusion. In order to minimize changes in insulin concentrations during somatostatin infusion, insulin-treated alloxanized sheep were used. Lowered glucagon concentrations after somatostatin infusion were associated with reduced glucose production and decreased blood glucose and β-hydroxybutyrate concentrations. This suggests that glucagon participates in maintaining the basal rate of gluconeogenesis in sheep and can influence hepatic ketogenesis.
THE DRY MATTER INTAKE AND DIGESTIBILITY OF WINTER WHEAT HARVESTED AS WHOLE CROP SILAGE
Authors: FISHER L. J. , LESSARD J. R.
Published: March 2010

Wheat was harvested for silage at the milk, the soft dough and the firm dough stages of maturity and fed to lactating cows in a comparison with corn silage harvested at 30% dry matter. The protein content of the four silages ranged from 7 to 8.3%. The crude fiber content of the corn silage (22%) was lower than that of the three wheat silages ranging from 27.4% at the firm dough stage to 34.5% at the milk stage. Silage dry matter intake was highest for the firm dough wheat silage and lowest for the corn silage. However, there was no significant difference in milk yield or milk composition among the four silages. The higher intake of the firm dough silage compared to corn silage was compensated for by the tendency of higher digestibility of the corn silage. The rumen acetate content of the cows fed soft dough wheat silage was higher than for those fed corn silage and milk stage wheat silage, while the reverse was true for rumen propionate.
EFFECTS OF VIRGINIAMYCIN ON THE PERFORMANCE OF PIGS FED BARLEY DIETS SUPPLEMENTED WITH SOYBEAN MEAL OR LOW-GLUCOSINOLATE RAPESEED MEAL
Authors: CASTELL A. G.
Published: March 2010

Ninety-six pigs, fed ad libitum from 10 to 94 kg liveweight, were used to examine the effects of including virginiamycin, at 0 and 1.102 g/100 kg diet, in starter and grower diets containing a low-glucosinolate rapeseed meal (Brassica napus L. cv. Tower) or soybean meal. Virginiamycin supplementation significantly increased growth rates, by 4.6% pre 33 kg liveweight and 5.1% subsequently, but produced a nonsignificant (P > 0.05) improvement in feed: gain ratios (2.8 and 0.5%, respectively). Use of the antibiotic did not significantly affect carcass criteria. Using the oilseed meals at 7.5% in the starter period and 12.5% subsequently, replacement of soybean meal by rapeseed meal resulted in a decrease in growth rates (from 546 to 518 g/day, P < 0.05, and from 754 to 706 g/day, P < 0.01, respectively) and poorer feed:gain ratios (2.38 vs. 2.51 kg feed/kg gain, P < 0.05, and 3.69 vs. 3.85, NS, respectively). Carcass differences between the pigs fed soybean meal or rapeseed meal were not significant (P > 0.05). The results suggest that the extent of the response to growth-promoting levels of virginiamycin may be influenced by dietary components.
RELATIVE PREFERENCE BY MULE DEER FOR SIX SHRUBS FROM RANGE NEAR KAMLOOPS, BRITISH COLUMBIA
Authors: TUCKER R. , McLEAN A. , WALDERN D. E.
Published: March 2010

Adult does preferred snowbrush, Douglas fir and Rocky mountain maple and avoided Saskatoon serviceberry, big sagebrush and gray rabbitbrush. Juvenile deer preferred Douglas fir, accepted snowbrush and Rocky mountain maple and avoided Saskatoon serviceberry, big sagebrush and gray rabbitbrush. Adults differed from juveniles in the preference for snowbrush and Douglas fir.
EFFECTS OF SOW NUTRITION IN LATE GESTATION ON THE BODY COMPOSITION AND SURVIVAL OF THE NEONATAL PIG
Authors: OKAI D. B. , AHERNE F. X. , HARDIN R. T.
Published: March 2010

One hundred and two sows were fed either 2.0 kg/day (C–L) or ad libitum a control diet (C–H) or diets containing 10% added sucrose (SU) or 10% stabilized tallow (TA) from day 100 of gestation until parturition. Level of nutrient intake or source of energy in the sows’ diet did not significantly influence the number or weight of pigs born or the number of pigs weaned. The survival of pigs of less than 1.0 kg birthweight was significantly greater for sows fed the C–H diet. At weaning, pigs from sows fed the SU diet were significantly (P < 0.05) heavier than those from sows receiving the other three treatments. Pigs from the sows fed TA were heavier (P < 0.05) at weaning than those from sows fed C–L or C–H. There were no significant differences in the proximate composition of the colostrum from sows on any of the four treatments. Proximate carcass composition of the pigs at birth, 24 or 48 h of age was similar for pigs from all four sow treatments. The fatty acid content of the carcass lipid of the newborn pig was not significantly affected by sow feeding regimen. Carcass proximate analyses and fatty acid content of the carcass lipid were significantly (P < 0.01) affected by age of pig at slaughter.
DIAMETER OF MUSCLE FIBERS AND COMPOSITION OF SELECTED RETAIL CUTS FROM CATTALO AND HEREFORD CARCASSES
Authors: KELLER D. G. , LAWSON J. E. , PETERS H. F.
Published: March 2010

Cattalo (averaging 1/7 bison–6/7 domestic) and Hereford yearlings (eight males and eight females in each breed group) did not differ in the surface areas of the total cut, lean, fat, bone, or connective tissue in either blade or cross-rib cuts. For cross-rib cuts, ratios of lean area to fat area, total surface area, and carcass weight were larger within cattalo than Hereford. Cattalo and Hereford did not differ in diameter of muscle fibers from the longissimus dorsi of the blade cut or the biceps femoris of the round cut, but muscle fibers from the 1. dorsi of the rib cut had a greater diameter in cattalo than in Hereford yearlings. Females had a larger proportion of fat and a smaller proportion of lean than males in both the blade and cross-rib cuts, but the proportion of bone was about the same. Muscle fiber diameter did not differ between the sexes in samples from the blade and rib cuts; however, it was greater for females than for males in samples from the round.
EFFECTS OF RATION AND INSIDE VERSUS OUTSIDE HOUSING ON PLASMA LEVELS OF ASCORBIC ACID, LACTIC ACID, GLUCOSE AND CHOLESTEROL IN HEREFORD STEERS WINTERED UNDER PRACTICAL CONDITIONS
Authors: HIDIROGLOU M. , IVAN M. , LESSARD J. R.
Published: March 2010

The relationship between housing and blood plasma concentrations of ascorbic acid, lactic acid, glucose, and cholesterol were studied with 60 yearling Hereford steers. One half of the steers were wintered (November–April) inside a barn and the other half in an open yard. Each group was subdivided into two treatments and fed hay or hay plus cracked barley. During a pre-experimental period (July–October) all steers were on pasture. The steers fed hay + grain gained approximately twice as much as the steers fed hay only. However, the steers housed inside gained only slightly more than those kept outside. There were only small differences in feed intakes between the inside and outside steers. Levels of all measured metabolites fluctuated during the pre-experimental period (July–October) when all steers were on pasture. During November–January, animals wintered inside showed a larger decrease in plasma glucose and increase in plasma ascorbic acid than did those wintered outside. Plasma lactic acid and cholesterol levels also decreased during this time but the differences between rations were larger than those between types of housing; the levels were lower in animals fed hay plus barley than in those fed hay only. No direct correlation between plasma levels of lactic acid, glucose, and cholesterol and cold stress were established. However, some changes in plasma levels of ascorbic acid might have been associated with cold exposure.
EFFECTS OF ALFALFA CONSUMPTION ON ESTROGEN LEVELS IN EWES
Authors: NEWSOME F. E. , KITTS W. D.
Published: March 2010

The effects of the alfalfa phyto-estrogens, mostly coumestrol and genistein, on circulating levels of endogenous estrogens in ewes is presented. Both estrogens and phyto-estrogens were measured by competitive binding assay after separation on sephadex LH-20 columns. During the 21 days of the trial, the five ewes consuming orchard grass had higher and more variable plasma estrogen levels than the ewes fed alfalfa. The five ewes on alfalfa hay consumed an equivalent of 177 mg genistein per day and showed plasma levels of 5–30 ng genistein equivalents/ml, while ewes on orchard grass hay had no detectable plasma phyto-estrogens. It is suggested that the plasma levels of phyto-estrogens resulting from the consumption of alfalfa could be high enough to compete with the endogenous estrogens for sites on the estrogen binding protein in the hypothalamus of the ewes and thus influence the production of gonadotropins and so depress the functioning of the ovary.
VALUE OF WHOLE PLANT FABA BEAN SILAGE AS THE SOLE FORAGE FOR LACTATING COWS
Authors: McKNIGHT D. R. , MacLEOD G. K.
Published: March 2010

Lactating Holstein cows fed either whole plant faba bean silage or grass–legume silage as sole forage produced similar yields of milk of comparable composition. Dry matter intake and body weight gain were greater for cattle fed faba bean silage, but apparent digestibility of dry matter, protein and energy, and proportions of rumen volatile fatty acids were similar.
EFFECTS OF DIETARY MANGANESE LEVELS ON REPRODUCTIVE PERFORMANCE OF EWES AND ON TISSUE MINERAL COMPOSITION OF EWES AND DAY-OLD LAMBS
Authors: HIDIROGLOU M. , HO S. K. , STANDISH J. F.
Published: March 2010

Two groups of eight 2-yr-old ewes were fed a low manganese (Mn) synthetic diet (8 ppm Mn) either with or without Mn supplementation (60 ppm Mn). The diets were fed for a 5-mo period prior to breeding and throughout gestation. Manganese supplementation of the diet resulted in higher blood Mn concentration. More services per conception were required for the ewes fed the low Mn diet than were required for the ewes fed the Mn-supplemented diet. The calcium content of kidney and muscle tissues, the magnesium content of spleen and the zinc content of the heart were found to be lower in ewes fed supplemental Mn, while the zinc content of the spleen was found to be higher. The calcium levels in the heart and kidney and iron levels in the liver and lung were higher in the day-old lambs born to Mn-supplemented ewes, while the magnesium level in the heart was lower. It is suggested that the calcium response of the ewes on low Mn diet to the physiological demands of fetal development may have been impaired by a reduction in dietary Mn.
EFFECTS OF AGE, BREED AND FLOOR TYPE ON THE INCIDENCE OF ARTICULAR CARTILAGE LESIONS IN PIGS
Authors: PERRIN W. R. , AHERNE F. X. , BOWLAND J. P. , HARDIN R. T.
Published: March 2010

Articular cartilage lesions of a mild degree were observed in pigs shortly after weaning, indicating that the condition can occur in the very young pig. There were no significant differences (P < 0.05) between breed or floor type in the incidence or severity of cartilage lesions. There were significant (P < 0.05) increases in the incidence and severity of cartilage lesions with increasing weights of pigs, the largest increase occurring between 60 and 120 kg liveweight. The lesion score of the left proximal femur was the only joint lesion score significantly correlated with average daily gain. The highest incidence and severity of lesions occurred in the distal humerus and proximal femur. Levels of several blood serum constituents were not significantly correlated with the degree or severity of cartilage lesions. Mineralization of the compact bone appeared to be normal in pigs showing cartilage lesions, and there were no significant correlations between lesion score and bone mineral content.
EFFECT OF SELECTION FOR LEAN GROWTH RATE UPON FEED UTILIZATION BY THE MARKET HOG
Authors: SATHER A. P. , FREDEEN H. T.
Published: March 2010

Results from an individual feeding trial comparing the feedlot and carcass performance of pigs from two populations, an index selected line and a genetic control, are described. The populations were initiated in 1961, the select line restructured in 1972, and the present evaluation made on progeny born in 1976. The index was based on two traits, growth rate and backfat. Feedlot data for 123 pigs indicated a direct genetic response of.94 standard deviation units (SDU) for rate of feedlot gain and correlated responses of −1.07 SDU for days on test, −1.22 SDU for total feed required and −1.07 SDU for feed/gain ratio. Carcass data for 96 pigs indicated a direct genetic response of −1.51 SDU for average backfat and a correlated response of 1.21 SDU for carcass index. In economic terms (1976 values), the improvement in carcass merit represented an increased revenue of $3.04 per pig, the increased growth rate was equivalent to a 10% reduction in the fixed costs and non-feed variable costs per pig, and the correlated response in feed requirements reduced feed costs by $3.13 per pig. Practical implications in respect of pig testing programs are discussed.
EVALUATION OF HOLSTEIN-FRIESIAN DAIRY SIRES FOR CONFORMATION OF THEIR DAUGHTERS
Authors: SCHAEFFER L. R. , BURNSIDE E. B. , HUNT M. S.
Published: March 2010

A model is described for evaluating dairy sires for the conformation of their daughters accounting for age at classification, year, classification of the dam, genetic trend, and sire effects. Results of the application of this model to two data sets are presented. Estimates of genetic trend for type traits indicated at least twice as much progress is being made for type as for milk production.
THE INTAKE AND DIGESTIBILITY OF AMMONIATED CEREAL STRAWS BY CATTLE
Authors: HORTON G. M. J.
Published: March 2010

The effects of treatment with 3.5% anhydrous ammonia on the nutritive value of straws from Neepawa wheat, Bonanza barley and Random oats were investigated with growing Hereford steers. Ambient temperatures during the 6-wk post-treatment period were 0.1 °C for wheat and barley straws and 15 °C for oat straw. The four treatments were untreated and ammoniated straw, fed with or without 4-kg supplements per day over four periods to four steers in a 4 × 4 latin square design. Crude protein was doubled in wheat and barley straws and trebled in oat straw following ammoniation. The consumption of all three straws without concentrates was increased significantly by ammoniation. Apparent digestibility of dry matter and crude fiber on straw rations were higher (P < 0.05) in ammoniated wheat and oat straw than in the corresponding untreated straws. Neither straw intake nor dry matter digestibility were improved (P > 0.05) by ammoniation when supplements were fed, though crude fiber digestibility was increased (P < 0.05) in wheat and oat straw rations. Straw treatment had no effect (P > 0.05) on ruminal pH, dehydrogenase activity, or total or molar proportions of volatile fatty acids. Ruminal ammonia concentrations were higher (P < 0.01) for ammoniated than for untreated straws fed alone and similar to those when concentrates were also fed. Plasma urea, measured 0, 0.5, 1, 2, 4 and 7 h post-prandial, was highest in steers fed ammoniated wheat and oat straw and lowest when untreated straw was fed alone.
ESTROGEN-INDUCED LH AND FSH RELEASE IN OVARIECTOMIZED EWES: EFFECT OF SEASON
Authors: HOWLAND B. E. , BEATON D. B. , SANFORD L. M. , PALMER W. M.
Published: March 2010

Five ovariectomized ewes were each injected i.m. with 50μg estradiol-17β in oil at 1800 h on 9 June, 19 July, 2 Sept. and 20 Oct. Serum samples of jugular blood, collected at 1-h intervals from 12 or 13 h to 30 h after estrogen treatment were assayed for LH and FSH. With the exception of one ewe in July, estrogen consistently induced a rise in serum LH. A rise in serum FSH accompanied the LH rise in only two of the five animals. The interval between estrogen injection and peak gonadotropin levels decreased (P < 0.05) between July and October but no difference was observed in either the peak gonadotropin levels or amount of LH released. The data suggest that estrogen-treated ovariectomized ewes do not respond consistently with a release of both LH and FSH and that the transition from anestrous to the breeding season is associated with a slightly shorter interval between estrogen injection and peak gonadotropin levels.
THE FEEDING VALUE POTENTIAL OF POTATO VINES
Authors: NICHOLSON J. W. G. , YOUNG D. A. , McQUEEN R. E. , JONG H. DE , WOOD F. A.
Published: March 2010

The potential use of green potato (Solanum tuberosum L.) vines as a livestock feed was investigated. Fresh vines contained less than 12% dry matter (DM) and did not produce a stable silage in plastic bag, laboratory silos. Satisfactory silages were produced by wilting or by the addition of barley, malt, barley + malt, molasses, chopped hay, chopped hay + barley + malt, formaldehyde and/or formic acid. Only the silages from wilted vines or those containing hay had a suitable consistency for storage and handling in conventional silage systems. Sheep readily ate a silage made from potato vines with the addition of 5% barley, 0.5% malted barley and 20% chopped hay or straw. The dry matter content of the vines from two cultivars changed only slightly over a 5-wk sampling period but the acid detergent fiber (ADF) content increased and the N content dropped. Except for the cultivar Wischip, there was little variation among nine cultivars sampled on the same day for pH (5.15–5.95), DM (10.3–12.9%) and ADF (26.5–32.4%). The N content ranged from 1.6 to 2.4% of the DM and the water soluble carbohydrate content from 7.5 to 3.3% of the DM. The levels of glycoalkaloids found should be safe for ruminant animals. It was concluded that potato vines harvested prior to senescence contain a useful level of nutrients for ruminants. Pesticide residues and mechanical systems for harvesting the vines are major concerns to be resolved before on-farm application can be recommended.
FACTORS AFFECTING RYE (SECALE CEREALE L.) UTILIZATION IN GROWING CHICKS. II. THE INFLUENCE OF PROTEIN TYPE, PROTEIN LEVEL AND PENICILLIN
Authors: MISIR R. , MARQUARDT R. R.
Published: March 2010

Three experiments were conducted to evaluate the influence of protein type, protein level and penicillin on the utilization of rye by growing chicks. The effects of the following dietary ingredients, respectively, were studied: meat meal or fish meal in rye or wheat diets containing 18 or 26% crude protein, increasing levels of penicillin in rye diets containing meat meal or fish meal, and two levels of penicillin in rye or wheat diets containing meat meal or fish meal. The results indicate that the type (quality) and level (quantity) of the dietary protein plus penicillin affected chick performance. As a dietary ingredient, rye consistently depressed chick growth and the efficiency of feed utilization relative to wheat; these adverse effects were accentuated by feeding rye diets containing a low level of a lower quality protein. However, supplementation of these diets with penicillin or a higher quality protein markedly alleviated these effects. The maximum improvement in chick performance was achieved with rye diets containing fish meal plus penicillin compared to those containing meat meal without penicillin; these relative changes for rye and wheat diets, respectively, were: +121 and +26% for weight gain; +35 and +5% for feed intake, −39 and −17% for feed:gain, +11 and −1% for dry matter retention and +83 and +30% for protein retention. Results would suggest that rye contains factor(s) that reduce(s) the utilization of nutrients, particularly protein. Penicillin supplementation appears to have a protein-sparing effect, particularly when the dietary protein quality and/or levels are suboptimal.
HIGH-UREA PROTEIN SUPPLEMENTS FED AD LIBITUM TO WINTERING BEEF CALVES
Authors: HIRONAKA R.
Published: March 2010

Six-month-old steer calves consumed, ad libitum, 0.38–0.87 kg/head/day of a supplement containing 13% urea and 6% rapesecd-oil soapstock. No symptoms of urea toxicity were observed. The addition of sulphur to the high-urea supplements did not produce any beneficial effects.
EFFECT OF DIETARY SELENIUM ON GLUTATHIONE PEROXIDASE ACTIVITY IN PIGLETS
Authors: CHAVEZ E. R.
Published: March 2010

Two experiments were conducted to measure the effect of dietary selenium on glutathione (GSH) peroxidase activity in plasma and body organs of growing pigs. In experiment 1, 12 piglets weaned at 2 wk and 18 weaned at 4 wk were fed for a period of 5 wk either a selenium-deficient basal diet or the same diet supplemented with 0.1 ppm selenium as sodium selenite. Three levels of dietary vitamin E supplemented as dl-alpha-tocopheryl acetate were also included in this experiment in a factorial arrangement with selenium. Vitamin E was shown to have no effect on GSH-peroxidase activity. In contrast, dietary selenium exerted a significant effect on the activity of the seleno-enzyme in the plasma, pancreas, heart, lungs and kidneys of piglets. The kidneys showed the highest GSH-peroxidase activity of the organs studied. Supplemental selenium resulted in a marked increase in plasma GSH-peroxidase activity of the piglets weaned at 2 wk, and maintained a high level of activity for those weaned at 4 wk. Pancreatic activity of this enzyme in selenium-deficient animals showed a drop to about one-third the activity observed in selenium-supplemented piglets after a 5-wk period. GSH-peroxidase in heart muscle showed the same response that was observed in the pancreas. The reduction in activity of this enzyme in lungs and kidneys was much greater than in pancreas and heart. No measurable amounts of GSH-peroxidase were observed in the liver of piglets either with or without selenium supplementation. In experiment 2, six pairs of male-female piglets weaned at 2 wk of age were fed either a selenium-deficient or a selenium supplemented diet. During the 20-wk period, selenium-supplemented piglets showed an average GSH-peroxidase activity in plasma 8.2-fold higher than selenium-deficient animals. After 2 wk, selenium-deficient piglets showed an extremely low activity of the seleno-enzyme in the plasma. Thus, the measurement of GSH-peroxidase in plasma of the live animal appears to be a reliable index of nutritional selenium status in piglets.
EFFECTS OF FEEDING OF CHONDRUS CRISPUS (IRISH MOSS) DURING THE GRAZING SEASON ON THE CONDITION AND FERTILITY OF SHROPSHIRE EWES
Authors: BREWER D. , McLACHLAN J. , NEISH A. C. , TAYLOR A. , MacINTYRE T. M.
Published: March 2010

Shropshire ewes grazing permanent pastures were dosed once weekly with Chondrus crispus (Irish Moss) from May to September or October during the years 1973 to 1977. The seaweed was fed at 250 g wet wt/wk/ewe by oesophageal tube. At these dose levels, C. crispus is not chronically toxic to grazing ewes. Both fertility and post-lactation weight gains of the C. crispus-dosed ewes on pasture were enhanced as compared to the control flock. By contrast, the performance of female lambs from the C. crispus-dosed ewes was indistinguishable from that of female lambs from the control flock.
A TECHNIQUE FOR DEPLETION OF BACTERIA ADHERENT TO THE EPITHELIUM OF THE BOVINE RUMEN
Authors: CHENG K.-J. , BAILEY C. B. M. , HIRONAKA R. , COSTERTON J. W.
Published: March 2010

Rumens of fistulated cattle were manually emptied, washed with a buffered saline solution, and then filled with buffered saline with or without added antibiotic. After 3 days without feed, cattle were slaughtered and blocks of rumen epithelium were assayed for urease and prepared for scanning electron microscopy. Urease activity in treated animals was less than 3% of that in controls, thus indicating almost complete removal of urease-producing bacteria, and scanning electron microscopy showed a dramatic decrease in the number of adherent bacteria. The technique can thus be used to assess the relative contributions of epithelium and adherent bacteria to various processes known to occur at the epithelial boundary.
LAMB GROWTH PERFORMANCE OF CERTAIN PURE BREEDS AND THEIR 2-, 3-, and 4-BREED CROSSES
Authors: VESELY J. A. , PETERS H. F.
Published: March 2010

Weaning weight, post-weaning gain, and final market weight were studied on 1734 lambs from Romnelet, Columbia, Suffolk, and North Country Cheviot breeds of sheep and their 2-, 3-, and 4-breed crosses. Several least-squares models were used; all included factors for year, age of dam, sex, birth type, and regression of the trait on age of lamb, and differed in the classification according to the genetic makeup of the lambs. Weaning weights of the purebred, and 2- and 3-breed cross lambs were significantly different (24.4, 25.6, 26.6 kg, respectively). Post-weaning gains of the three mating types were also significantly different but in a different ascending order, 19.4 kg for purebreds, 19.9 kg for 3-breed crosses, and 20.6 kg for 2-breed cross lambs. Final market weights of the purebred, and 2- and 3-breed cross lambs were 43.7, 46.3, and 46.4 kg. Means of the three traits from 3-breed cross lambs were similar to those from 4-breed cross lambs. Lambs sired by 2-breed cross rams did not perform on the average better than the lambs sired by purebred rams. Purebred Suffolk rams sired lambs that were markedly better in the production traits than those sired by the other three pure breeds and were equal to or better than those sired by crossbred rams. Only Suffolk × North Country Cheviot rams sired lambs that outperformed the lambs sired by the Suffolk rams but the differences were small.
EFFECTS OF FEEDING PROGRAMS AND DIET ENERGY ON RATE OF GAIN, EFFICIENCY OF DIGESTIBLE ENERGY UTILIZATION, AND CARCASS GRADES OF STEERS
Authors: HIRONAKA R. , SONNTAG B. H. , KOZUB G. C.
Published: March 2010

Two experiments were conducted to obtain biological data to expand a linear programming (LP) model for feedlot cattle management and to test that model by feeding model-formulated diets of different digestible energy (DE) concentrations. In the first experiment, 76 steers averaging 210 kg in body weight were fed an all-concentrate diet to gain at a low rate of about 0.5 kg/day (L), a medium rate of about 0.8 kg/day (M), or at a high rate when the diet was fed ad libitum (H). The five feeding programs were LMH, HML, MMM, HHH, and LLH. The HHH steers gained faster (1.15 kg/day) than those in the other groups (P < 0.01). However, the amount of DE (6260 Mcal) required to gain about 270 kg was similar among groups (P > 0.05). The steers restricted in feed during part of the feeding period produced leaner carcasses (P < 0.01) than those that were full-fed throughout. In the second experiment, 75 Hereford or Hereford-Angus steers averaging about 200 kg in body weight were fed diets differing in DE concentrations to test the LMH program of the LP model. The rate of gain declined and DE/gain ratio increased as the DE concentration of the diet was decreased. Carcass measurements and grades were similar among groups fed diets differing in DE concentrations.
EFFICACY AND SAFETY OF FEED ADDITIVE USE OF ANTIBACTERIAL DRUGS IN ANIMAL PRODUCTION
Authors: HAYS V. W. , MUIR W. M.
Published: March 2010

The magnitude and consistency of response to antibacterial agents varies with stage of the production cycle and with the environmental conditions to which the animals are exposed. The level and the spectrum of the drug used contributes to the response; the drugs more effective as therapeutic agents are also more effective as feed additives. A major part of the variation in response among experiments can be attributed to variations in environmental conditions, the initial health status of the animals and the inability to account for normal variation in growth rate and feed conversion with the minimal number of replications used in most experiments. Tissue residues and microbial resistance are the main concerns for human health safety when using antibacterial drugs, the most pressing concerns currently being with the sulfa drugs for tissue residues and with tetracycline and penicillin for microbial resistance. The effects of feed additive usage of antibacterials on efficacy of antibiotics in human medicine are difficult to assess. In animals, the documented evidence supports the thesis that the benefits of this usage outweigh any loss of effectiveness for animal drug therapy. At present, proposals have been submitted in the United States to discontinue the use of penicillin and tetracyclines as feed additives, reserving them for prescribed prophylactic and therapeutic veterinarian use.
EFFECTS OF BREED AND SEX ON THE RELATIVE GROWTH AND DISTRIBUTION OF BONE IN PIGS
Authors: RICHMOND R. J. , JONES S. D. M. , PRICE M. A. , BERG R. T.
Published: March 2010

The growth and distribution of bone from 179 pig carcasses were compared among five breeds (Duroc × Yorkshire (D × Y), Hampshire × Yorkshire (H × Y), Yorkshire (Y × Y), Yorkshire × Lacombe-Yorkshire (Y × L-Y) and Lacombe × Yorkshire (L × Y)) and two sex-types (barrows and gilts) over a wide range in carcass weight. The growth pattern for each bone relative to total side bone was estimated from the growth coefficient, b, in the allometric equation (Y = aXb). Growth coefficients were homogeneous in this study among breeds and between sexes for each bone, indicating that the different breeds and sexes followed similar patterns of relative bone growth as they increased in size. The lowest growth coefficients (b < 1.0) were found among the limb bones (tarsus, femur, and radius/ulna). The thoracic vertebrae, carpus, tibia, humerus, sternum, pelvic and pectoral girdles had growth coefficients not significantly different from 1.0, while the ribs, lumbar and cervical vertebrae, patella and atlas had growth coefficients significantly greater than 1.0. Significant breed and sex differences were found in the weights of individual bones when adjusted to equal side bone weights. However, these were small and may reflect differences in stage of skeletal maturity.
CHONDROITIN SULFATE DISTRIBUTION IN STIFLE ARTICULAR CARTILAGE OF SWINE
Authors: NAKANO T. , AHERNE F. X. , THOMPSON J. R.
Published: March 2010

Chondroitin sulfate (ChS) was determined histologically and chemically at seven sites from four selected areas of distal femoral articular cartilage from each of five 90-kg boars. The concentration of ChS was higher (P < 0.05) in the force-bearing than in the non-force-bearing areas of the cartilage. Site differences in cartilage thickness and collagen concentration were also observed.
EFFECTS OF TEMPERATURE AND FEED INTAKE ON PLASMA CONCENTRATION OF THYROID HORMONES IN BEEF CATTLE
Authors: CHRISTOPHERSON R. J. , GONYOU H. W. , THOMPSON J. R.
Published: March 2010

In each of two experiments, plasma concentrations of thyroxine (T4) and triiodothyronine (T3) and the Free Thyopac Index (FTI) were determined, at intervals during winter, in beef steers housed either indoors in a heated barn or in outdoor pens. During experiment 2, a comparison was also made of the effects of four feed intake levels ranging from one to two times maintenance. In both experiments, plasma concentrations of T4 and FTI values were higher in steers kept outdoors than those kept indoors. The highest plasma T4 concentrations and FTI values were recorded in outdoor steers on a maintenance level of feed intake during February when the mean outdoor temperature was −15 °C. Under these circumstances, increasing the level of feed intake to twice maintenance reduced plasma T4 concentrations and FTI values. Level of feed intake had no effect on either plasma T4 or FTI values in steers kept in a heated barn. Plasma T3 concentrations were higher in the outdoor than the indoor steers during experiment 2. Reducing feed intake from twice maintenance to maintenance levels resulted in a decrease in plasma T3 concentrations in steers kept outdoors, but not in those kept indoors in a heated barn. These results indicate that thyroid hormone responses of cattle to cold environments are influenced by the level of feed intake.
A COMPARISON OF FRESH AND FROZEN SEMEN IN THE INSEMINATION OF CONFINED SHEEP
Authors: LANGFORD G. A. , MARCUS G. J. , HACKETT A. J. , AINSWORTH L. , PETERS H. F. , WOLYNETZ M. S.
Published: March 2010

The reproductive performance of crossbred sheep maintained in total confinement was compared after artificial insemination with fresh or frozen semen. Estrus was synchronized with progestagen-impregnated vaginal sponges and pregnant mares’ serum gonadotropin. Inseminations were performed 54 and 60 h after sponge removal. The fertility of ewes inseminated with fresh semen was significantly higher than of ewes inseminated with frozen semen. Conception rates, lambing rates and litter size were 83%, 78% and 2.2 using fresh semen and 65%, 43% and 1.8 using frozen semen. In a group of similar ewes bred by natural service, the lambing performance was comparable to that obtained with fresh semen. The difference between conception and lambing rates suggests an increase in early embryonic mortality when breeding with frozen semen and confirms the need for improved frozen semen technology.
DISTRIBUTION OF BLOOD FLOW IN COLD STRESSED PIGLETS
Authors: WILLIAMS P. E. V. , PARKER R. O. , YOUNG B. A. , AHERNE F. X.
Published: March 2010

Radioactive ruthenium labelled microspheres 15 ± 3 μm in diameter were used to determine distribution of cardiac output in unfed control (35 °C) and unfed cold stressed (5 °C) piglets 3.5 h of age. The cold stress produced an average 7.1 °C drop in rectal temperature and a redistribution of blood flow. In cold exposed piglets the adrenal fraction of cardiac output was significantly (P < 0.05) lower: 0.56% in the control compared with 0.29% in the cold exposed piglets; however, the relative blood flow to the adrenals was higher than for other tissues. The fractions of cardiac output reaching the psoas and biceps muscles increased (P < 0.05) by 148 and 260%, respectively, during cold exposure, while that reaching the heart, brain, alimentary tract, skin and fat was not significantly (P > 0.05) affected by cold exposure.
BLOAT IN FEEDLOT CATTLE: EFFECTS ON RUMEN FUNCTION OF ADDING 4% SODIUM CHLORIDE TO A CONCENTRATE DIET
Authors: CHENG K.-J. , BAILEY C. B. , HIRONAKA R. , COSTERTON J. W.
Published: March 2010

Four fistulated cows were given alfalfa hay or all-concentrate diets containing either 0.5% or 4.0% NaCl (salt). The low-salt diet leads to the development of rumen conditions associated with bloat. When given the low-salt concentrate diet, cows had rumen fluid with lower pH and protozoal counts, and higher viscosity, soluble carbohydrate concentration, and dry matter content than when they were given alfalfa hay or the high-salt concentrate diet. Massive lysis of bacterial cells was observed in rumen digesta from cows on the low-salt diet and intact cells were full of reserve carbohydrate granules and were surrounded by thickened fibrillar capsules. These changes were largely absent in cows on the other two diets. Water intake and the total water content of the rumen were lower with the low-salt diet than with the other diets. The flow of water through the rumen was highest with alfalfa hay, lowest with the low-salt diet, and intermediate with the high-salt diet. It was concluded that adding 4.0% NaCl to an all-concentrate diet of a type implicated in feedlot bloat increased the flow of material from the rumen and, in so doing, appeared to alter fermentation in such a way as to oppose development of conditions that lead to bloat.
THE DEGRADATION AND UTILIZATION OF ENDOGENOUS UREA IN THE GASTROINTESTINAL TRACT OF RUMINANTS: A REVIEW
Authors: KENNEDY P. M. , MILLIGAN L. P.
Published: March 2010

Urea transferred from the blood to the digestive tract of ruminants is potentially an important source of nitrogen for microbial growth in the reticulorumen and hind gut. Early attempts to assess the quantitative importance of urea transfer did not distinguish between its reticuloruminal and hind gut components. However, recent advances in tracer methodology have facilitated this partition, and a number of estimates have been made, principally using sheep on roughage diets. For some roughage diets, the rate of urea transfer to the rumen of sheep was small and was attributable to salivary urea, whereas for other diets substantial amounts of urea appeared to be entering the rumen across the rumen epithelium in addition to that carried in saliva. Regression analysis indicated that the rate of transfer of endogenous urea to the rumen of sheep given those diets was associated with the concentration of rumen ammonia and of plasma urea, and with the amount of organic matter digested in the rumen. Experimental evidence supporting the validity of this concept is discussed. Relationships are presented which show that the clearance of plasma urea to the rumen is inversely proportional to the concentration of rumen ammonia in both sheep and cattle, but that clearance is increased by the addition of grain or sucrose to the diet. It is concluded that transfer of urea across the rumen epithelium may contribute significantly to the nitrogen economy of the microorganisms, but the mechanism by which such transfer is controlled by the ruminant remains obscure.
THE IN VITRO RELEASE OF AMINO ACIDS BY RUMEN PAPILLAE
Authors: BOILA R. J. , MILLIGAN L. P.
Published: March 2010

Rumen papillae from cattle were incubated aerobically with combinations of NH4Cl, amino acids and salts of organic acids, the latter including propionate, pyruvate, α-ketoglutarate and glyoxylate. Amino acids in the incubation media were analyzed using a gas-liquid chromatographic technique entailing separation of the isobutyl-N(0)-heptafluorobutyryl esters: glutamine was recovered with glutamate, asparagine with aspartate, and citrulline with ornithine. Rumen papillae incubated with pyruvate or propionate released alanine, but with the latter substrate only glutamate was effective as a nitrogen source. Glycine and glutamate plus glutamine were released in the presence of glyoxylate and α-ketoglutarate, respectively. Serine and aspartate plus asparagine were not quantitatively major products released by rumen papillae. Glutamate was an effective source of nitrogen for the release of alanine and glycine with pyruvate and glyoxylate, respectively, as carbon sources. When rumen papillae were incubated with pyruvate or glyoxylate as the added carbon source, glutamine nitrogen disappeared and was not accounted for by the amino acids measured. With arginine as a substrate, there was a release of ornithine by rumen papillae indicating urea production. The tissues of rumen papillae appear to synthesize amino acids from expected carbon sources with ammonia or glutamate as nitrogen sources and to catabolize glutamine and arginine. The metabolism of amino acids by rumen papillae would contribute to the interchange of nitrogen between the rumen and the host.
ABOMASAL BLOAT AND GAS PRODUCTION IN THE DIGESTIVE TRACT OF LAMBS
Authors: ARSENAULT G. , BRISSON G. J. , SEOANE J. R. , JONES J. D.
Published: March 2010

The effect of different protein sources on gas production in the rumen, abomasum and intestine was studied in 26 lambs fed milk replacers. The sources of protein were either skim milk powder, rapeseed protein concentrate, Promosoy 100, or an experimental soybean protein concentrate. Rapeseed and soybean protein concentrates supplied 53% of the total protein in the diets. Milk replacers containing 15% DM were offered ad libitum at 37 °C, twice a day for 21 days. A high incidence of abomasal bloat was observed between the 15th and the 18th day of feeding but this was not related to the protein sources or to the quantity of milk replacer ingested. However, gas production by the gut contents from non-bloating lambs was higher when they were fed the two soybean protein concentrates (212 and 190 μL/mL/10 min) than from those fed the rapeseed and skim milk powder concentrates (125 and 118 μL/mL/10 min). Ruminal and abomasal gas productions of non-bloating lambs averaged 121 and 17 μL/mL/10 min, respectively, and were similar for the four diets. When bloat occurred, abomasal gas production was 4–15 times higher than in the non-bloaters (17 vs. 195 μL/mL/10 min) which confirmed the fact that the abomasum is an important site of gas production. A "maladjustment syndrome" probably related to a malfunction of the esophageal groove was observed in three lambs. In these lambs, gas production and pH in the rumen and in the abomasum were the same.
METABOLISM OF ALIPHATIC NITRO COMPOUNDS IN BOVINE RUMEN FLUID
Authors: MAJAK W. , CLARK L. J.
Published: March 2010

Metabolic studies with rumen fluid were conducted to determine rates of disappearance for 3-nitropropanol (3NPOH) and 3-nitropropionic acid (NPA), forage constituents which can be toxic to ruminants and non-ruminants. The in vitro rate of disappearance for NPA was substantially greater (P < 0.01) than for 3NPOH. The nitro compounds were metabolized most effectively when the inoculum originated from cattle fed orchardgrass soilage as compared with orchardgrass hay, alfalfa soilage or alfalfa hay. The in vivo ruminai clearance rate was substantially greater (P < 0.05) for 3NPHO than for 2-nitropropanol, a nitro compound which was not metabolized in vitro and this would be predicted if metabolism in the rumen contributed to the rate of 3NPOH disappearance.
EFFECT OF SULFUR SUPPLEMENTATION ON IN VITRO CELLULOSE DIGESTION AND ON NUTRIENT UTILIZATION AND NITROGEN METABOLISM OF LAMBS FED LOW QUALITY FESCUE HAY
Authors: GUARDIOLA C. M. , FAHEY Jr. G. C. , SPEARS J. W. , GARRIGUS U. S.
Published: March 2010

Experiments were conducted to determine the effects of supplementing low quality tall fescue hay, containing 0.26% total sulfur, with an iso-sulfurous quantity of either sodium sulfate or D,L-methionine. In vitro experiments were carried out where rumen fluid was collected from sheep fed a similar low quality tall fescue hay. In experiment 1, the addition of 1% urea to the low quality fescue ration stimulated in vitro cellulose digestion (P <.001). The addition of 0.05%, 0.10% and 0.15% sulfur from either sodium sulfate or methionine also stimulated cellulose digestion (P <.001) with no difference due to sulfur source. In experiment 2, the addition of 0.8% nitrate-N added as potassium nitrate depressed in vitro fescue cellulose digestion (P <.001) regardless of whether the donor sheep were adapted or unadapted to nitrate in the ration. Addition of sulfur appeared to overcome the depression in cellulose digestion due to nitrate. In vivo experiments involved the use of 12 crossbred female lambs (average initial weight, 34 kg) which were randomly assigned to one of three treatments (fescue, no added sulfur; fescue plus 0.15% sulfur as sodium sulfate; and fescue plus 0.15% sulfuras D,L-methionine). After completion of trial 1, lambs were re-randomized and the trial was replicated. Acid detergent fiber (ADF) and neutral detergent fiber (NDF) digestibilities were improved (P <.01) by supplemental sulfur, regardless of sulfur source. Nitrogen retention was not significantly affected by treatment. Essential amino acids, expressed as a percent of the total amino acids, were higher (P <.01) for lambs receiving the 0.15% sulfate-S diet. Molar percentage of methionine was increased (P <.01) by the addition of sulfur to the control diet whereas phenylalanine and glutamine concentrations decreased with sulfur addition. Serum taken from lambs fed 0.15% methionine-S contained more histidine (P <.05) while lambs fed 0.15% sulfate-S had less (P <.05) serum glycine.
EVALUATION OF THE TWO-STAGE TECHNIQUE FOR THE IN VITRO ESTIMATION OF THE DRY MATTER DIGESTIBILITY OF CORN SILAGE
Authors: BOILA R. J. , ERFLE J. D. , SAUER F. D.
Published: March 2010

The two-stage Tilley and Terry technique (incubation with rumen fluid followed by an acid-pepsin digest), used to estimate dry matter (DM) digestibility of forages in vitro, was evaluated with oven-dried corn silage as a substrate. The effect of weight of substrate (100–3000 mg), continuous shaking of incubations for the period of incubation with rumen fluid, number of bacteria present in the inoculum, and the contribution of bacterial dry matter to residual feed DM was measured. Percent dry matter digested decreased linearly as weight of substrate per incubation tube increased. Continuous shaking, as opposed to intermittent mixing (twice daily) during incubation with rumen fluid, increased the rate of DM disappearance and resulted in higher digestibility coefficients. Both the volume of inoculum and the number of bacteria present in that volume of inoculum influenced the percent DM digested. Bacteria contribute weight to residual feed DM unless steps are taken to remove them by centrifugation or solubilization.
A COMPARISON OF GROWTH AND CARCASS CHARACTERISTICS BETWEEN HOLSTEIN-FRIESIAN STEERS AND SIMMENTAL × HOLSTEIN (F1) CROSSBREDS
Authors: FORREST R. J.
Published: March 2010

The carcass characteristics of 42 purebred Holstein-Friesian (Hol) steers were compared with 64 (37 steers and 27 heifers) Simmental (Sim) × Hol, F1 crossbreds. These offspring were the product of three Holstein and three imported Simmental sires. A portion of the calves (20 Holstein; 18 crossbred steers and 13 heifers) were individually fed to provide growth and feed consumption data. There were no significant differences in either rate of gain or feed efficiency between the purebred and crossbred steers at any growth stage between 200 and 500 kg body weight. The heifers were significantly (P < 0.05) less efficient between 300 and 500 kg and grew more slowly (1.09 compared to 1.62 kg/day) between 400 and 500 kg than the steers. Carcass characteristics were taken after slaughter at constant weight (500 kg). The Holsteins dressed lower (56.3%) than the crossbreds (57.4%). The Holsteins had less hide (33.4 kg) than either the crossbred heifers (37.9 kg) or steers (40.4 kg). However, the Holsteins had heavier livers (6.73 kg) and kidneys (1.11 kg) than the crossbred steers (6.16 and 1.01 kg) which in turn had significantly heavier livers and kidneys than the crossbred heifers (5.71 and 0.87 kg). The crossbred heifers had the greatest amount of offal fat, 33.5 kg, the crossbred steers the least, 19.8 kg, whereas the Holsteins were intermediate with 25.0 kg. The Holsteins were longer in the body, deeper in the chest, and thinner at the shoulder and round than the crossbred groups. The two steer groups were similar in carcass proportions, whereas the heifers were lighter in the chuck and shank areas and heavier in the back and belly regions. The crossbred heifers had the lightest (503 g) but most dense metatarsal bones (SG = 1.594) while the Holsteins had the longest (26.3 cm) and the crossbred steers the least dense (SG = 1.533) metatarsal bones. In carcass composition, the crossbred heifers had the most fat, 20.7%, whereas the steers of both breeds averaged 15.8%. The Holstein had the most bone (13.4%) and the heifers the least (12.1%) while the crossbred steers were intermediate (12.8%). With respect to lean, the heifers had the least (67.2%) while the crossbred steers had the most 71.8%) and the Holsteins were intermediate (70.4%).