Showing papers in "Journal of Animal Science in 1991"

Animal welfare: concepts and measurement.

Abstract: The term “welfare” refers to the state of an individual in relation to its environment, and this can be measured. Both failure to cope with the environment and difficulty in coping are indicators of poor welfare. Suffering and poor welfare often occur together, but welfare can be poor without suffering and welfare should not be defined solely in terms of subjective experiences. The situations that result in poor welfare are reviewed in this study with special reference to those in which an hdividual lacks control over interactions with its environment. The indicators of poor welfare include the following: reduced life expectancy, impaired growth, impaired reproduction, body damage, disease, immunosup pression, adrenal activity, behavior anomalies, and self-narcotization. The uses of measures of responsiveness, stereotypies, and animal preferences in welfare assessment are discussed. The need to make direct measurement of poor welfare as well as to use sophisticated studies of animal preferences is emphasized.

National beef tenderness survey.

Abstract: To determine the average tenderness and sensory ratings of beef subprimal cuts sold in retail cases across the United States, retail cuts were purchased through typical retail outlets in 14 metropolitan cities and transported to Texas A&M University for sensory and Warner-Bratzler shear analysis. The overall mean shear force for all cuts was 3.65 kg, and the mean shear force values for chuck, rib, loin, and round cuts were 3.72, 3.36, 3.17, and 4.31 kg, respectively. No difference (P greater than .05) in tenderness was detected among the cuts from the rib. Mean palatability ratings and shear force values of top loin steaks were similar to those of rib cuts. Top sirloin steaks were tougher (P less than .05) and received the lowest sensory ratings compared with other loin cuts. Approximately two to three times as many round and chuck steaks had shear force values in excess of 4.6 kg compared with their roast counterparts. In all cases, roasts tended to be more tender than steaks from the same subprimal source. USDA Choice chuck retail cuts, compared to Select and No-roll chuck cuts, had approximately 10% fewer cuts with shear force values in excess of 4.0 kg. More work is needed to improve meat tenderness, primarily for retail cuts from the round and chuck primals. Future research must investigate the interaction of antemortem and postmortem factors associated with variation in beef tenderness.

Effects of the inclusion of yeast culture (Saccharomyces cerevisiae plus growth medium) in the diet of dairy cows on milk yield and forage degradation and fermentation patterns in the rumen of steers.

Abstract: The effects of including yeast culture (YC; Saccharomyces cerevisae plus growth medium; 5 x 10(9) organisms/g) in diets for ruminants was examined in two experiments. In Exp. 1, 32 multiparous Friesian dairy cows were fed between wk 7 to 12 of lactation one of four completely mixed diets based on either hay or straw plus rolled barley (mixed to give concentrate:forage ratios of either 50:50 or 60:40, respectively) with or without 10 g YC/d in a 2(3) factorial design. Supplementation with YC increased DM intake of the cows by a mean of 1.2 kg/d (P less than or equal to .062) and increased milk yield by 1.4 liters/d (corrected to 4% butterfat; P less than or equal to .05). There was an interaction (P less than .05) between diet composition and YC addition; effects of YC were greatest in diets containing 60:40 (concentrate:forage) ratio. In Exp. 2, three steers were fed a diet of 50% hay and 50% rolled barley (DM basis). Hay was available for the major part of the day but barley was fed in two meals/d. Addition of YC to the diet increased (P less than .05) ruminal pH for 4 h after the barley meal. This elevation in pH probably was due to a reduction (P less than or equal to .01) in the concentration of L-lactate in the ruminal liquor of steers given YC (1.43 vs 3.55 mM; P less than or equal to .01). Peak ruminal L-lactate concentration (7.75 mM) in the controls coincided with time of minimum pH values (2 h after the meal of barley); this peak was absent in steers given YC. YC had no effect on the concentration of VFA in ruminal liquor, but the ratio of acetate to propionate was reduced (P less than or equal to .01) from 3.3:1 to 2.8:1 in steers given YC. The extent of DM degradation of hay incubated in the rumen of steers fed the hay and rolled barley diet was increased (P less than .05) in the presence of YC at 12 h of incubation, but degradation was similar in all treatment groups after 24 h of incubation. Presence of yeast culture in the rumen had effects on ruminal stoichiometry. An increased rate of forage degradation may have increased forage intake and productivity of these dairy cows.

Effects of dietary fat on metabolic disorders and reproductive performance of dairy cattle

Abstract: Improved reproductive performance and reduced incidence of metabolic disorders have been postulated to be benefits of feeding supplemental fat to dairy cows. Increased plasma nonesterified fatty acid concentrations during fat supplementation may result from incomplete tissue uptake of fatty acids after lipoprotein lipase hydrolysis of very-low-density lipoprotein triglyceride; however, evidence suggests that net adipose tissue triglyceride hydrolysis may be increased during fat supplementation. Plasma 3-OH-butyrate concentrations remain relatively constant during fat supplementation but may have a tendency to be reduced if fat is supplemented to cows having relatively high basal plasma 3-OH-butyrate concentrations. Because plasma ketone levels usually increase when nonesterified fatty acid concentrations are elevated, it is hypothesized that potential antiketogenic effects of added fat are due to a glucose sparing effect. Supplemental fat does not seem to reduce hepatic lipid infiltration near the time of calving. Potential mechanisms by which supplemental fat may improve reproductive performance include stimulation of prostaglandin F2 a synthesis and secretion and enhanced utilization of blood cholesterol for progesterone synthesis. Days postpartum until first ovulation and luteal function of dairy cattle have been related to energy balance during the first 3 wk postpartum. Energy balance data for early lactation cows fed supplemental fat are not plentiful; however, slight but statistically nonsignificant increases have been observed when feeding fat. Cows fed supplemental fat that experience improved energy balance may begin to cycle sooner because of enhanced follicular growth and development. Applied studies examining the effects of supplemental fat on reproductive performance have provided inconsistent results.

Postmortem proteolysis in longissimus muscle from beef, lamb and pork carcasses

Abstract: Postmortem proteolysis in skeletal muscle and factors affecting this process were examined in pork, lamb and beef longissimus muscles 0 to determine the cause of differences in meat tenderness among these species. Fat thickness differed among species in the following order: pork > beef > lamb. The following patterns were observed for rate of temperature and pH decline: lamb > pork > beef and pork > beef > lamb, respectively. At 1 d postmortem, pork was the most tender, followed by beef and lamb, respectively. Between 1 and 14 d of postmortem storage, lamb LM was the most improved in tenderness, followed by beef and pork, respectively. Species did not differ (P > .05) in LM collagen solubility. Pork LM from fed pigs had the highest (P c .05) level of cathepsins B .e L and cystatin(s) activities, whereas no differences (P > .05) were observed among the species for cathepsin B activity. The lowest (P c .01) Ca2+depen&nt protease (COP)-II and CDP inhibitor activities were observed in pork LM. Beef LM had the highest CDP inhibitor activity (P c .05) but was intermediate in CDP-II activity. No differences were observed among species for CDP-I activity. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of myofibrils isolated at 0, 1 and 14 d postmortem indicated that by d 1, desmin hydrolysis was most extensive in pork muscle, followed by lamb and beef. This difference in the rate of myofibrillar protein hydrolysis may account for the differences observed in the rate of postmortem tenderization in LM among these species.

Aquaculture disease and health management.

Abstract: Disease problems constitute the largest single cause of economic losses in aquaculture In 1988, channel catfish producers lost over 100 million fish worth nearly $11 million Estimates for 1989 predict even higher losses The trout industry reported 1988 losses of over 20 million fish worth over $25 million No data are available on losses sustained by producers of shellfish Bacterial infections constitute the most important source of disease problems in all the various types of production Gram-negative bacteria cause epizootics in nearly all cultured species Fungal diseases constitute the second most important source of losses, especially in the culture of crustaceans and salmon External protozoan parasites are responsible for the loss of large numbers of fry and fingerling fin fishes and are a cause of epizootics among young shellfish The number of therapeutants approved by the Food and Drug Administration is limited Research to support the registration of promising therapeutic agents is urgently needed

Supplemental fat in high-energy rations for lactating cows: effects on intake, digestion, milk yield, and composition

Abstract: Supplemental fats (SF) have special value in the diets of dairy cows with superior productive ability, because the high energy density of SF allows greater energy consumption and direct transfer of the fatty acids (FA) of the SF to milk fat; this increases metabolic efficiency. Some SF, especially oils with a high degree of unsaturation, disturb ruminal fermentation, decrease fiber digestibility, and lower milk fat test; however, oilseeds (e.g., whole cottonseed) can be fed without observable ruminal inhibition, probably because of a slow release of the oil into ruminal contents. A number of commercial fat supplements are available that have little effect on ruminal fermentation and are highly digestible postruminally. A product of the calcium salts of palm oil fatty acids was shown to have a NE for lactation of more than three times that of corn. As the emphasis in milk pricing formula changes from milk fat to milk protein, there is greater concern regarding the propensity of fat supplements to decrease milk protein (casein) percentage. In two studies, a supplement of ruminally protected lysine and methionine largely prevented the reduction in casein percentage that occurred with feeding SF, indicating that the amino acid profile of undegraded dietary protein is important with regard to preventing the lower casein percentage. Combining fat supplements that are slowly released in the rumen with those that are inert in the rumen will allow maximal use of SF.

Effect of a Saccharomyces cerevisiae culture on lactate utilization by the ruminal bacterium Selenomonas ruminantium.

Abstract: The objective of this study was to examine the effects of a Saccharomyces cerevisiae culture (YEA-SACC) on lactate utilization by the predominant ruminal bacterium Selenomonas ruminantium. Lactate uptake was stimulated by YEA-SACC concentrations between 2.5 and 10 g/liter, and the 5-g/liter level increased uptake 3.8-fold. When YEA-SACC concentrations were increased above the 5-g/liter level lactate uptake was decreased, but 10 g/liter still stimulated uptake more than threefold. A filter-sterilized YEA-SACC filtrate also increased lactate uptake more than fourfold at all concentrations tested (10 to 100 microliters/ml), and the 25-microliters/ml level increased uptake ninefold. Growth of S. ruminantium in medium that contained 2 g/liter of DL-lactate was stimulated more than twofold by either 2 or 5% (vol/vol) YEA-SACC filtrate after 24 h. The YEA-SACC filtrate also increased the production of acetate, propionate, total VFA, and YLACTATE (grams of cells/mole of lactate) from lactate-grown cells. Because the increase in propionate production was greater relative to acetate, a decrease in the acetate:propionate ratio was observed. Growth on lactate and uptake of radiolabeled lactate by S. ruminantium was stimulated by a filter-sterilized YEA-SACC filtrate. The concentration of L-malic acid in the YEA-SACC filtrate was 4.9 mM, and it seemed that L-malic acid played a role in the stimulation of growth on lactate as well as lactate uptake by S. ruminantium treated with YEA-SACC.

An evaluation of tenderness of the longissimus muscle of Angus by Hereford versus Brahman crossbred heifers.

Abstract: Postmortem aging of carcasses obtained from Angus-Hereford (n = 8) and 5/8 Brahman crossbred (n = 8) heifers was investigated to determine the cause of variation in meat tenderness Raw longissimus muscle (LM) myofibril fragmentation index was lower and cooked LM Warner-Bratzler shear force was greater for the 5/8 Brahman crossbreds (P less than 05) The activities of calcium-dependent protease (CDP) -I and -II were not affected (P greater than 05) by breed; however, CDP inhibitor activity was higher (P less than 05) in the 5/8 Brahman carcasses The activities of cathepsins B and B + L were not affected by breed or postmortem storage time (0, 1, 3, 7 or 14 d) Hereford-Angus carcasses were fatter opposite the 12th rib and had higher USDA yield grades and marbling scores (P less than 05) Hereford-Angus crossbreds had less dark, coarse band formation around the exterior of the LM and lighter, finer-textured lean (P less than 05) Cooking loss (%) and cooking rate (g/min) were not affected by breed or postmortem aging (P greater than 05) The increased toughness in the 5/8 Brahman carcasses may be due to increased CDP inhibitor activity

The implications of cognitive processes for animal welfare

Abstract: In general, codes that have been designed to safeguard the welfare of animals emphasize the importance of providing an environment that will ensure good health and a normal physiological and physical state, that is, they emphasize the animals' physical needs. If mental needs are mentioned, they are always relegated to secondary importance. The argument is put forward here that animal welfare is dependent solely on the cognitive needs of the animals concerned. In general, if these cognitive needs are met, they will protect the animals' physical needs. It is contended that in the few cases in which they do not safeguard the physical needs, it does not matter from a welfare point of view. The human example is given of being ill. It is argued that welfare is only adversely affected when a person feels ill, knows that he or she is ill, or even thinks that he or she is ill, all of which processes are cognitive ones. The implications for welfare of animals possessing certain cognitive abilities are discussed. For example, the extent to which animals are aware of their internal state while performing behavior known to be indicative of so-called states of suffering, such as fear, frustration, and pain, will determine how much they are actually suffering. With careful experimentation it may be possible to determine how negative they feel these states to be. Similarly, the extent to which animals think about items or events absent from their immediate environment will determine how frustrated they are in the absence of the real item or event but in the presence of the cognitive representation.

Development of a culture system for bovine granulosa cells: effects of growth hormone, estradiol, and gonadotropins on cell proliferation, steroidogenesis, and protein synthesis.

Abstract: The objectives of the present studies were 1) to develop a culture system that has the positive effect of serum on granulosa cell attachment and allows subsequent expression of hormonal effects in serum-free medium and 2) to determine the effect of insulin, epidermal growth factor (EGF), estradiol (E2), and growth hormone (GH) on growth, steroidogenesis, and(or) protein synthesis of bovine granulosa cells. Cells from small (1 to 5 mm) and large (greater than 8 mm) follicles were collected from cattle and cultured for either 4 or 6 d. When cells from small follicles were cultured, insulin (5 micrograms/ml) increased (P less than .05) cell numbers (cells x 10(5)/well) severalfold compared with controls. Alone, EGF (10 ng/ml), FSH (200 ng/ml), LH (200 ng/ml), E2 (2 micrograms/ml), or GH (0 to 1,000 ng/ml) had no effect on cell numbers. However, when included with insulin, 30, 100, and 300 ng/ml of GH increased (P less than .05) granulosa cell numbers on d 4 of culture. Insulin alone increased (P less than .05) progesterone production (ng.10(5) cells-1.24 h-1) by severalfold on d 4, but EGF, FSH, LH, or GH alone had no effect and E2 inhibited progesterone production. In the presence of insulin, FSH and GH (100 ng/ml) increased (P less than .05) progesterone production on d 4 of culture, whereas EGF (10 ng/ml) elicited a decrease (P less than .05) in production. In cells from both sizes of follicles, GH (300 ng/ml) increased synthesis of cellular proteins (greater than 10 kDa). In cells from only large follicles, LH (200 ng/ml) decreased synthesis and secretion of proteins (greater than or equal to 3.5 kDa). These results support the hypothesis that GH may have direct effects on bovine ovarian function.

Responses of cortisol and prolactin to sexual excitement and stress in stallions and geldings.

Abstract: Sexual stimulation induces rapid secretion of cortisol and prolactin (PRL) in stallions. Experiment 1 was designated to determine whether stallions associated location and(or) procedure with previous sexual stimulation in that location. After a control period on d 1, four stallions were exposed to an estrous mare for 5 min on d 2. On d 3, 4, 5, and 6, the same procedure was followed with no mare present. Concentrations of PRL and cortisol increased (P less than .05) after mare exposure on d 2 but did not vary (P greater than .05) on d 1, 3, 4, 5, or 6. In Exp. 2, six stallions were used to determine the short-term effects of 1) sexual stimulation, 2) acute physical exercise, 3) restraint via a twitch (twitching), 4) epinephrine administration, and 5) no stimulation on plasma concentrations of PRL and cortisol. Stallions received one treatment per day separated by 2 d of no treatment. Concentrations of cortisol increased (P less than .05) within 10 min after sexual stimulation, exercise, twitching, and epinephrine administration but not during control bleedings. Concentrations of PRL increased (P less than .05) immediately after sexual stimulation, exercise, and twitching but not after epinephrine administration or during control bleeding. In Exp. 3, the same five treatments were administered to six geldings. Concentrations of cortisol increased (P less than .05) after epinephrine administration, exercise, and twitching but not after sexual stimulation or during control bleedings. Concentrations of PRL increased (P less than .05) after exercise and sexual stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Interrelationship between hypersensitivity to soybean proteins and growth performance in early-weaned pigs.

Abstract: The objective of this growth trial was to determine the interrelationship between immunological criteria, gut morphology, and performance of starter pigs fed soybean proteins processed by different methods. One hundred twenty-five pigs were orally infused with 6 g/d of either dried skim milk, soybean meal (48% CP), soy protein concentrate, extruded soy protein concentrate, or experimental soy protein concentrate from 7 to 11 d of age and then fed a diet containing the same protein sources from weaning (d 21) to 35 d of age. All pigs were fed a corn-soybean meal diet containing 10% dried whey, 1.25% lysine, and 3% soybean oil for the remaining 21 d of the experiment. Xylose absorption and anti-soy immunoglobulin G (IgG) titers were measured on d 6 postweaning, and skin-fold thickness after intradermal injection of protein extracts was measured on d 7 postweaning. A total of 25 pigs (five pigs/treatment) was euthanatized on d 7 postweaning. Villus height and crypt depth from duodenum samples were measured. These measurements were obtained to elucidate a relationship between the hypersensitivity responses to soybean products and growth performance of baby pigs. Pigs fed diets containing soybean meal had a lower (P less than .05) rate of gain (d 0 to 14) and villus height, higher (P less than .01) serum anti-soy IgG titers, and increased skin-fold thickness (d 6 and 7 postweaning) after intradermal injection compared with those fed dried skim milk. Pigs fed other soy proteins also had lower ADG from d 0 to 14 postweaning; however, pigs fed moist extruded soy protein concentrate tended (P less than .09) to have higher ADG and improved feed utilization when compared with pigs fed soybean meal (d 0 to 14).(ABSTRACT TRUNCATED AT 250 WORDS)

Measuring suitability of soybean products for early-weaned pigs with immunological criteria.

Abstract: Two trials were conducted to determine the suitability of soybean products for baby pigs. Weanling pigs (n = 40 and 48 in Trials 1 and 2, respectively) were infused orally (6 g/d) with dried skim milk, soybean meal (SBM, 48% CP); soy protein concentrate, moist extruded soy protein concentrate, or soy protein isolate from d 7 to 12 of age. Pigs were then fed a diet containing the same protein source for 1 (Trial 1) or 2 (Trial 2) wk after weaning (d 21 of age). To avoid exposure of pigs to soybean proteins, the dams of pigs were fed a corn-corn gluten meal-based diet supplemented with lysine and tryptophan from d 109 of gestation. All pigs in Trial 1 were killed at 28 d of age, and samples of ileal digesta and small intestine were obtained. In Trial 2, the soy protein isolate was not included, and all pigs were fed a diet containing 4% soybean oil and 1.25% lysine for the last 3 wk of the trial. Growth performance, skin-fold thickness, after intradermal injection of extracts of the corresponding proteins, and anti-soy immunoglobulin G (IgG) titers were measured. Results indicated that pigs fed diets containing SBM had lower (P less than .05) villus height and xylose absorption but higher (P less than .05) serum anti-soy IgG titers and increased skin-fold thickness compared with the mean of pigs given milk and all other soy treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of pig weaning weight and associated nursery feeding programs on subsequent performance to 105 kilograms body weight.

Abstract: An experiment using a total of 210 crossbred pigs from two farrowing groups evaluated the effects of three weaning weights and their associative starter feeding program on subsequent postweaning performance to 105 kg BW. One group of pigs nursed their dams in outside heated hutches (Trial 1), and a second group was raised in a centrally heated farrowing house (Trial II). The three pig weaning weight groups ranged in weight from 1) 4.1 to 5.0 kg, 2) 5.5 to 6.8 kg, and 3) 7.3 to 8.6 kg. Pigs in Group 1 were fed a high nutrient dense diet (HNDD) for a 2-wk period followed by a corn-soybean meal-dried whey (C-SBM-DW) and then a corn-soybean meal (C-SBM) diet, each for a 2-wk period. Group 2 was fed the same diet sequence except that HNDD was provided for 1 wk, whereas Group 3 was provided only the C-SBM-DW and the C-SBM diets each for 2 wk, consecutively. At the end of the nursery period, pigs were fed C-SBM diet formulations to 105 kg BW. Pigs of Trial I averaged 5.2 d older at weaning than those raised in the central farrowing house, but only a 1.5-d difference existed between light- and heavy-weight groups in both trials. Gains and feed intakes for the three weaning groups were higher as weaning weight increased during both the nursery and the growing-finishing period. There did not seem to be a compensatory growth response for lighter-weight weanling pigs even though they had been fed starter diets containing milk products. Consequently, fewer days (approximately 15) were required for the heavier-weight weanling pig group to reach a final weight of 105 kg than for the light-weight group. The medium-weight group required an intermediate number of days to reach 105 kg.

Physical and chemical components of the empty body during compensatory growth in beef steers.

Abstract: The composition of carcass and noncarcass tissue growth was quantified by serial slaughter of 26 Angus x Hereford crossbred steers (initial age and weight 289 +/- 4 d and 245 +/- 4 kg) during continuous growth (CON) or compensatory growth (CG) after a period of growth restriction (.4 kg/d) from 245 to 325 kg BW. All steers were fed a 70% concentrate diet at ad libitum or restricted levels. Homogenized samples of 9-10-11th rib and noncarcass tissues were analyzed for nitrogen, fat, ash, and moisture. Growth rate from 325 to 500 kg BW was 1.54 and 1.16 kg/d for CG and CON steers. The weight of gut fill in CG steers was 10.8 kg less (P less than .05) before realimentation and 8.8 kg more (P less than .10) at 500 kg BW than in CON steers. The allometric accretive rates for carcass chemical components relative to the empty body were not affected by treatment. However, the accretive rates for CG steers were greater (P less than .01) for noncarcass protein (.821 vs .265), noncarcass water (.861 vs .507), and empty-body protein (.835 vs. .601) than for CON steers. Final empty-body fat was lower (P less than .001; 24.2 vs 32.4%) and empty-body protein higher (P less than .001; 16.6 vs 14.8%) in CG steers than in CON steers. Consequently, net energy requirements for growth (NEg) were approximately 18% lower for CG steers. We conclude that reduced NEg requirements and changes in gut fill accounted for most of the compensatory growth response exhibited in these steers.

Influence of breed, number of suckling lambs, and stage of lactation on ewe milk production and lamb growth under range conditions.

Abstract: Milk production and lamb growth were characterized in 118 multiparous, 3- to 7-yr-old Rambouillet, Columbia, Polypay, and Suffolk ewes under spring sage range and high mountain meadow grazing from 28 to 98 d postpartum. Daily milk yield as measured by the lamb suckling weight differential technique did not differ (P greater than .05) among breeds, although milk production of Suffolk ewes tended to be higher than that of the other three breeds. Within the Rambouillet, Columbia, and Polypay breeds, total estimated yield of ewes with twins was 13 to 17% higher than that of ewes with singles, whereas in the Suffolk breed, suckling twins increased total milk yield 61% over that of ewes with singles. Twin lambs induced a larger differential in dam milk production in late lactation (70 to 98 d) than in earlier lactation (28 to 70 d). Number of lambs did not influence milk protein, Ca, or P content (P greater than .05). Fat levels in colostrum and 4-d milk were elevated 14 and 20%, respectively, in ewes suckling twins compared with ewes suckling singles. Under range conditions, Suffolk ewes suckling single or twin lambs lost more BW (12 and 21% of 4-d postpartum body weight, respectively) than Rambouillet (4 and 7%), Columbia (5 and 8%), or Polypay (8 and 8%) ewes. Correlation coefficients of milk production and lamb growth rate were positive and significant (P less than .05) up to 56 d of age. Growth rate was less closely associated with milk production for twin than for single lambs.

Extender and centrifugation effects on the motility patterns of slow-cooled stallion spermatozoa.

Abstract: Slow-cooled stallion spermatozoa, with and without seminal plasma removed by centrifugation, were diluted in Kenney's extender (KE) containing nonfat dry skim milk with glucose and antibiotics or in KE supplemented by adding a modified high-potassium Tyrode's medium (KMT). Four ejaculates from each of four stallions were collected and divided factorially across these four treatments. Percentage of motile sperm, path velocity, and linearity immediately after treatment (0 h) and after storage at 4 degrees C for 24, 48, and 72 h were evaluated objectively by use of a HTM-2030 sperm motility analyzer. Stallions were a significant source of variation (P less than .01) throughout. After sperm had cooled, effects of stallion, extender, centrifugation, and their interactions were all found to be significant (P less than .01). The motility at 0, 24, 48, and 72 h for centrifuged KE was 74, 47, 39, and 24%; for uncentrifuged KE was 76, 56, 50, and 37%; for centrifuged KMT was 76, 75, 72, and 64%; and for uncentrifuged KMT was 80, 50, 26, and 13%, respectively. The extender x centrifugation interaction, after 24, 48, and 72 h of storage, accounted for half or more of the variation. Whereas centrifugation of semen extended in KE seemed to be harmful to sperm, motility of sperm extended in KMT after centrifugation was remarkably conserved for 72 h and was superior to all other treatments (P less than .05). This extender is promising for preserving liquid stallion semen when it must be transported before use in artificial insemination.

Reduced blood flow to peripheral and core body tissues in sheep and cattle induced by endophyte-infected tall fescue

Abstract: Four wethers and 14 steers (environmentally heat stressed, 32 degrees C, 60% relative humidity) were evaluated for changes in blood flow induced by endophyte-infected tall fescue. Concentration of the ergopeptide ergovaline was used as an indicator of diet toxicity due to the endophytic fungus Acremonium coenophialum. Blood flow to specific tissues was measured using radiolabeled microspheres. Wethers received one of two dietary treatments for 30 d before determination of tissue blood flow: 1) a low-endophyte diet (less than .05 ppm ergovaline) or 2) a high-endophyte (1.18 ppm ergovaline) diet. Blood flows to the adrenal glands and skin covering the inner hind leg were less (P less than .10) in wethers consuming the high-endophyte diet than in those consuming the low-endophyte diet. Tissue blood flows in steers were determined on two occasions: 1) after steers had received a low- (less than .01 ppm ergovaline) or high-endophyte (.52 ppm ergovaline) fescue diet for 14 d and 2) 8 d after steers had been switched to a common, fescue-free diet. Blood flows to skin covering the ribs, cerebellum of the brain, duodenum, and colon were less (P less than .10) in steers consuming the high-endophyte diet. However, 8 d after consuming fescue-free diets, steers that had previously consumed the high-endophyte diet had greater (P = .08) blood flow to the coronary bands of the front hooves than steers that had consumed the low-endophyte diet. Blood flows to all other tissues were similar between treatments. We inferred from these experiments that the toxin(s) associated with endophyte-infected tall fescue caused decreased blood flow to peripheral and core body tissues and that this effect was abated within 8 d of removing the toxin(s).

Influence of dietary energy on follicular development, serum gonadotropins, and first postpartum ovulation in suckled beef cows.

Abstract: Twenty-eight Hereford x Angus cows (4 yr of age) were used to determine the effects of pre- and postpartum dietary energy on performance and reproductive function in suckled beef cows. The experiment was designed as a 2 x 2 factorial with cows receiving either 70 (L) or 150% (H) of NRC recommended level of dietary energy before and(or) after parturition, resulting in four treatment combinations (L-L, L-H, H-L, H-H). Prepartum diets were fed for approximately 110 d, and postpartum diets were fed until either 10 d after the second postpartum ovulation or 150 d postpartum for those cows that failed to ovulate. Cows receiving low compared with high levels of energy before calving lost more (P less than .01) weight, body condition, subcutaneous fat, and longissimus muscle area before parturition and had calves with lighter (P less than .01) birth weights. Cows receiving low compared with high levels of energy postpartum lost more (P less than .01) weight, body condition, and longissimus muscle area after parturition. Low levels of energy before and after parturition decreased (P less than .01) milk production and calf weight at 70 d of age. Rates of cervical and uterine involution were unaffected by dietary energy treatments. Cows receiving high levels of energy prepartum had increased (P less than .01) mean concentrations and pulse frequency of LH in serum after parturition, and cows receiving high levels of energy postpartum had increased (P less than .05) pulse frequency of LH. Low levels of energy postpartum decreased (P less than .01) appearance rate of small (5.0 to 7.9 mm) and large (greater than or equal to 10 mm) follicles, and low levels of energy prepartum decreased (P less than .02) appearance rate of large follicles based on transrectal ultrasonography. Cows receiving high levels of energy prepartum had shorter (P less than .02) intervals from parturition to ovulation, and a higher (P less than .01) percentage of the cows that received high levels of energy postpartum ovulated by 150 d postpartum. In summary, prepartum level of dietary energy influenced birth weight and weight gain of calves, milk production, concentrations and pulse frequency of LH in serum, appearance rate of large follicles, and the interval to first ovulation. Postpartum level of dietary energy influenced milk production, weight gain of calves, pulse frequency of LH, appearance rate of small and large follicles, and the percentage of cows that ovulated after parturition.

Fatty acid elongation and desaturation enzyme activities of bovine liver and subcutaneous adipose tissue microsomes.

Abstract: Assay conditions were established for the fatty acid elongation and the delta 9 desaturase enzyme systems of bovine liver and adipose tissue microsomes; rat liver microsomes were used as a reference. Overall fatty acid elongation was determined by measuring the incorporation of [2-14C]malonyl-coenzyme A (CoA) to 14C-labeled stearate. Rat liver elongation activity was .50 +/- .02 nmol.min-1.mg protein-1; bovine liver microsomal elongation activity was substantially lower (P less than .05), with a mean value of .15 +/- .02 nmol.min-1.mg protein-1. The elongation activity of bovine s.c. adipose tissue microsomes (.42 +/- .10 nmol.min-1.mg protein-1) was not different (P greater than .05) from the activity observed in rat liver microsomes. To determine the fatty acid delta 9 desaturase activity, microsomes were incubated in the presence of [1-14C]stearoyl-CoA and nicotinamide adenine dinucleotide (reduced form) (NADH), and the production of radioactively labeled oleate was quantified. Microsomal delta 9 desaturase activity was similar in rat liver and bovine s.c. adipose tissue microsomes with rates of .15 +/- .04 and .21 +/- .05 nmol.min-1.mg protein-1, respectively. However, no desaturase activity was detected in bovine liver microsomes, indicating that the liver is not a major site of oleate synthesis in this species. To investigate differences in fatty acid metabolism relative to breed type, eight Angus and seven Braford heifers were slaughtered at approximately 12 mo of age. Subcutaneous fat thickness over the 12th-13th thoracic vertebrae was greater in the Angus heifers than in the Braford heifers. However, no differences (P greater than .05) were observed in mean adipocyte size or number of cells per gram of adipose tissue between the Angus and Braford heifers. Similarly, there were no significant differences between the Angus and Braford s.c. adipose tissues for microsomal fatty acid elongation or delta 9 desaturation, or for nicotinamide adenine dinucleotide phosphate (NADP)-malate dehydrogenase, fatty acid synthetase, or the pentose cycle reductases. The inability of bovine liver to convert stearate to oleate was in agreement with the fatty acid composition of the liver lipid, which had a smaller percentage of oleate and a higher percentage of stearate than s.c. adipose tissue.

Soybean protein solubility in potassium hydroxide: an in vitro test of in vivo protein quality.

Abstract: Experiments were conducted to assess protein solubility in .2% KOH as an indicator of soybean protein quality for chicks and pigs and to assess effects of particle size on protein solubility. As the particle size (micron) of soybean meal (SBM) increased, protein solubility (%) decreased (b = -.0206). In two 9-d chick trials, dehulled SBM (48% CP) was subjected to various autoclaving times and then fed as the sole source of dietary protein to young chicks. Increasing autoclaving times from 0 to 40 min at 120 degrees C resulted in a quadratic decrease in protein solubility. A broken-line model was fitted wherein gain:feed of chicks was plotted as a function of protein solubility. The analysis showed no reduction in feed efficiency with solubilities greater than 59 +/- 1.5% (mean +/- SEM). When solubility was below 59%, however, gain:feed decreased 1.5% for each 1% decrease in protein solubility. The third trial (13 d) was conducted with 7.5-kg pigs fed autoclaved SBM (44% CP) as the primary source of protein. Feed efficiency was significantly decreased when protein solubility was less than 66%. This study showed that protein solubility in KOH was a good index of in vivo soybean protein quality, and that it is important to standardize SBM particle size when applying the KOH assay.

The effect of source of fiber on ileal and fecal amino acid digestibility and bacterial nitrogen excretion in growing pigs.

Abstract: Studies were carried out with six barrows (initial BW 50 kg) to determine the effect of two fiber sources on the apparent ileal and fecal N and amino acid digestibilities and bacterial N excretion in feces. The pigs, fitted with a simple T-cannula at the distal ileum, were fed three cornstarch-based diets formulated to contain 16% CP from soybean meal according to a repeated 3 x 3 Latin square design. Diet 1 did not contain additional fiber. Diets 2 and 3 contained 10% powdered cellulose and 10% barley straw (ground through a 2-mm mesh screen), included at the expense of cornstarch, respectively. The pigs were fed 900 g at each meal twice daily, 0800 and 2000. Feces were collected for 48 h after a 10-d adaptation period. Thereafter, ileal digesta were collected for 24 h. Chromic oxide was used as a digestibility marker. With the exception of leucine, the inclusion of fiber did not affect (P greater than .05) the ileal digestibilities of the indispensable amino acids. The values for the average of the ileal digestibilities of the indispensable amino acids were 85.3, 82.9, and 83.2% for diets 1, 2, and 3, respectively. On the other hand, the inclusion of fiber decreased (P less than .05) the fecal digestibilities of all the indispensable amino acids. The values for the average of the fecal digestibilities of the indispensable amino acids were 91.7, 87.4, and 89.1% for diets 1, 2, and 3, respectively. These decreases resulted from an increase (P less than .05) in the excretion of bacterial N, which was measured using 2,6-diaminopimelic acid as a marker. In conclusion, as measured with the ileal analysis method, the inclusion of fiber had little effect on the digestible amino acid supply.

Using calcium chloride injection to improve tenderness of beef from mature cows.

Abstract: The objective of this investigation was to determine the effect of calcium chloride (CaCl2) injection on Warner-Bratzler shear force (WBS), sensory panel ratings, and collagen traits of mature cow beef. Within 30 min of exsanguination, subprimals (top round, TR; top sirloin, TS; strip loin, SL) from alternate sides of the carcass were injected with a .3 M CaCl2 solution (10% of the subprimal weight) and aged for 1, 7, or 14 d. The corresponding cold-boned cuts of the other side served as a control. Injecting CaCl2 eliminated the requirement for extended postmortem storage, as indicated by d 1 WBS. During the 14-d aging period, WBS of noninjected cuts decreased by 2.59 kg, whereas WBS of CaCl2-injected samples decreased by only .35 kg. Compared with control cuts, CaCl2 injection improved (P less than .05) d-14 WBS of steaks from SL, TS, and TR by 41.1, 40.1, and 15.3%, respectively. Additionally, CaCl2-injected subprimals exhibited higher (P less than .05) sensory panel tenderness ratings, lower (P less than .05) amounts of detectable connective tissue, and shorter (P less than .05) sarcomere lengths. No differences (P greater than .05) were observed in any quantitative collagen traits between CaCl2-injected and control cuts. These results indicate that CaCl2 injection improved ultimate tenderness and sensory ratings of meat from mature cow cuts.

Growth, body composition, and visceral organ mass and metabolism in lambs during and after metabolizable protein or net energy restrictions.

Abstract: Three trials were conducted to assess effects of metabolizable protein and NE deficiencies on changes in body composition, organ mass and metabolism, and animal growth performance during restriction and realimentation. Growth of lambs was restricted to achieve no change in BW for periods of 5 to 6 wk by limiting intake of metabolizable protein or NE. In Trial 1, changes in body composition and visceral organ mass and metabolism during restriction were compared to unrestricted controls using 36 lambs. Trial 2 was designed to investigate changes in growth, body composition, and visceral organs during restriction and realimentation periods using 44 lambs. Trial 3 was limited to evaluation of differences in performance and carcass characteristics of previously restricted and unrestricted ram lambs (15 total). Results of Trial 1 indicated that liver weights were decreased with nutrient restrictions. Body protein mass was conserved in energy-restricted (ER) lambs and lost in protein-restricted (PR) lambs. Fat was mobilized at similar rates for PR and ER lambs. In Trial 2, liver and intestinal weights, as well as in vitro oxygen consumption by liver slices, were decreased with nutrient restrictions. The reductions persisted after 2 wk of realimentation, yet no compensatory growth was observed. Feed intakes were increased gradually during the first 2 wk of realimentation. Composition of gain during the realimentation period was similar to that of unrestricted lambs. In Trial 3, neither gain nor feed efficiency during realimentation was enhanced as a result of previous nutrient deficiencies. Absence of compensatory growth in Trial 3 is possibly attributable to differences in gastrointestinal fill. Lambs subjected to short-term PR and ER seem to have similar recuperative capacity.

Energy balance, first ovulation and the effects of naloxone on LH secretion in early postpartum dairy cows.

Abstract: Relationship among energy balance (EB), first ovulation, circulating metabolites and opioid involvement in peripheral LH concentrations were assessed in 40 multiparous Holstein cows assigned randomly to an experiment with a 2 x 2 factorial arrangement of treatments. Cows were either milked normally (2x/d) and expected to be in negative EB (LAC) or were milked for only 1 d postpartum (PP) to ensure a rapid return to positive EB (NONLAC). Blood samples were collected from NONLAC cows every 12 min for 16 h on d 7, 10, and 14 PP and from LAC cows on d 7, 14, 21 and 28 PP. Within each group, half the cows received naloxone (50 mg/h) and half received saline during h 9 to 16 of each frequent sampling series. The mean number of LH pulses/8 h for NONLAC cows was 4.3, 4.7 and 5.3 at 7, 10 and 14 d PP and for LAC cows 4.3, 5.7, 6.4 and 7.0 at 7, 14, 21 and 28 d PP, respectively. The LH pulse frequency was not different between NONLAC and LAC cows at 7 and 14 d PP, yet NONLAC cows had fewer days to first ovulation (P less than .01). Naloxone did not affect any parameters of LH secretion in either group. Following parturition, NONLAC cows averaged 4.0 d to negative EB nadir and 14.3 d to first ovulation. The LAC cows averaged 13.6 d to negative EB nadir and 27.0 d to first ovulation. Days PP to first ovulation were highly correlated (r = .85) with days PP to negative EB nadir.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of environmental temperature on growth, muscle and adipose tissue metabolism, and meat quality in swine.

Abstract: An experiment involving 32 individually housed, castrated male pigs was conducted to determine the effects of environmental temperature (12 degrees C = T12 or 28 degrees C = T28) on the performance, carcass characteristics, muscle and adipose tissue metabolism, and meat quality of pigs fed to achieve equal rates of weight gain between 8 and 92 kg live weight. The T12 pigs had less muscle (P less than .01) and more subcutaneous fat (P less than .01) in the ham than did T28 animals. Thyroids and adrenals were heavier (P less than .01) in T12 than in T28 pigs. Percentage of type I muscle fibers was higher (P less than .01) and fiber cross-sectional areas smaller (P less than .01) in semispinalis muscle (SS) of T12 pigs, whereas no effect of temperature was noticed in longissimus muscle (LD). Cold exposure induced a larger increase in oxidative metabolism in SS (+30 to 32%, P less than .001) than in LD (+14 to 17%, P less than .10) and an enhanced glycolytic metabolism in LD (P less than .05). Lipid concentration was higher in SS of T12 than in that of T28 pigs. Lipogenic enzyme activities and unsaturation of backfat were higher in T12 than in T28 pigs, whereas no effect of temperature was noticed in leaf fat. Cold treatment resulted in a faster postmortem pH decline (P less than .01), higher glycolytic potential (P less than .01), and lower ultimate pH (P less than .01) in LD. The results indicate that 12 degrees C vs 28 degrees C induced detrimental effects on growth, ham composition, and muscle and adipose tissue quality.

Effects of calcium soaps of fatty acids on postpartum reproductive function in beef cows.

Abstract: Twelve multiparous Simmental cows (584 kg) were used to determine the influence of calcium soaps of fatty acids (CSFA) incorporated in a range supplement on postpartum reproductive characteristics. Cows were assigned randomly to receive a control [C; containing grain sorghum (GS) and soybean meal (SBM)] or CSFA-based (containing Megalac [a source of CSFA], GS, and SBM) supplement. Supplements plus prairie hay were individually fed. Diets were isonitrogenous and met the NEm requirement for heavy-milking beef cows in early lactation. Supplement feeding and daily blood collection began at parturition. Calves were removed permanently from cows at 25 +/- 2 d postpartum. Duration of first postpartum estrous cycles was determined by both visual observations and changes in concentrations of progesterone in serum. Concentrations of LH in serum (15-min intervals for 6 h) were determined 12 h before and 48 and 96 h after calf removal. Concentrations of progesterone and estradiol-17 beta in serum were determined daily. Cows receiving CSFA had higher (P = .06) mean concentrations of LH than those receiving C (1.47 vs 1.12 +/- .13 ng/ml). Concentrations of estradiol-17 beta were lower (P less than .02) and serum progesterone were higher (P less than .02) between d 6 and 8 of the induced cycle in CSFA-fed cows. Plasma cholesterol was greater (P less than .01) in cows fed CSFA although plasma triglyceride concentrations were similar between treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of the beta-adrenergic agonist L644,969 on muscle growth, endogenous proteinase activities, and postmortem proteolysis in wether lambs.

Abstract: To examine the effect of a beta-adrenergic agonist (BAA) on muscle growth, proteinase activities, and postmortem proteolysis, 16 wether lambs were randomly assigned to receive 0 or 4 ppm of L644,969 in a completely mixed high-concentrate diet for 6 wk. Weight of the biceps femoris was 18.6% heavier in treated lambs. At 0 h after slaughter, treated lambs had higher cathepsin B (35.6%), cathepsins B + L (19.1%), calpastatin (62.8%), and m-calpain (24.6%) than control lambs, but both groups had similar mu-calpain activities. In both longissimus and biceps femoris muscles, treated lambs had higher protein and RNA and lower DNA concentrations. However, total DNA was not affected, indicating that the increase in muscle mass was probably due to muscle hypertrophy rather than to hyperplasia. The pattern of postmortem proteolysis was significantly altered by BAA feeding. In treated lambs, postmortem storage had no effect on the myofibril fragmentation index and degradation of desmin and troponin-T. These results indicate that the ability of the muscle to undergo postmortem proteolysis has been dramatically reduced with BAA feeding. Similar proteolytic systems are thought to be involved in antemortem and postmortem degradation of myofibrillar proteins, so BAA-mediated protein accretion is probably due, at least in part, to reduced protein degradation. To examine whether protein synthesis was altered with BAA feeding, the level of skeletal muscle alpha-actin mRNA was quantified. Longissimus muscle alpha-actin mRNA abundance was 30% greater in BAA-fed lambs. Collectively, these results indicate that dietary administration of BAA increases muscle mass through hypertrophy and that the increase in muscle protein accretion is due to reduced degradation and possibly to increased synthesis of muscle proteins.

The pharmacokinetics and residues of clenbuterol in veal calves.

Abstract: Seven female Brown Swiss calves were used to study the pharmacokinetics of clenbuterol after an effective anabolic dosage of 5 micrograms/kg of BW was given twice daily for 3 wk. Analyses of clenbuterol concentrations in different tissues was done by enzyme immunoassay (EIA). Tissue samples were taken from three calves on the last day of administration and from two more after 3.5 or 14 d of clenbuterol withdrawal. The rate of clenbuterol elimination was dependent on time and tissue. Clenbuterol concentrations in the lung dropped from a mean of 76 ng/g to a level of less than .08 ng/g after 14 d, whereas in the liver the clenbuterol concentrations decreased from 46 ng/g to .6 ng/g within 14 d of withdrawal. Highest levels were always found in the eye: 118 ng/g, 57.5 ng/g, and 15.1 ng/g after 0, 3.5, and 14 d of withdrawal, respectively. These data reveal that different compartments contribute to the elimination of clenbuterol; therefore, concentrations in urine do not follow first order kinetics. An initial rapid decline in the concentration of clenbuterol in urine with a half-life of 10 h is followed by a slower elimination with a half-life of about 2.5 d. Treatments using the anabolic dose of 5 micrograms/kg of BW require longer withdrawal times than the therapeutic dose (.8 micrograms/kg BW).