bluuebunny/crossref_metadata_2025 huggingface dataset:
THE EFFECTS OF CHANGING SOW DIETARY FATTY ACIDS ON FETAL PLASMA FATTY ACID PATTERNS
Authors: FARNWORTH E. R. , KRAMER J. K. G.
Published: March 2010

Sows were fed a control diet or one with added tallow or soybean oil during gestation. Sow and fetal blood plasma fatty acids were determined at 57, 85 and 110 d gestation. The sow plasma fatty acid pattern, particularly 18:2n-6, was influenced by diet, but showed little change during gestation. High levels of polyunsaturated fatty acids, especially 18:2n-6 and 20:4n-6, were found in sow plasma. Fetal blood fatty acids were not directly influenced by maternal diet, but showed changes as gestation progressed. In the fetal plasma, 20:4n-6 was the major long chain polyunsaturated fatty acid, but in addition, high levels of 22:6n-3 were also found. The percent n-6 fatty acids were in higher concentrations than the n-3 fatty acids in both maternal and fetal plasma. Key words: Fetus, blood, fatty acids, swine
REVIEW OF COPPER DEFICIENCY AND METABOLISM IN RUMINANTS
Authors: GOONERATNE S. R. , BUCKLEY W. T. , CHRISTENSEN D. A.
Published: March 2010

The importance of copper (Cu) for the proper functioning of many biological systems is well recognized. Copper deficiency significantly affects ruminant livestock production in large areas of Canada as well as many other parts of the world. Selected aspects of recent research into Cu deficiency in ruminants have been reviewed, including the biochemistry and physiology of Cu deficiency as well as the metabolism of Cu. Because of the wide occurrence of Cu deficiency in ruminants grazing in areas of high molybdenum (Mo) and/or sulfur (S), research on the mechanisms of interference in Cu metabolism has received wide attention. Similarities in the physiological effects of the combination of molybdate and sulfide (or sulfate) and of thiomolybdates in ruminants, strongly suggest that thiomolybdates are primarily involved in the induction of Cu deficiency. Thiomolybdates appear to induce Cu deficiency by (i) limiting Cu absorption, (ii) binding Cu in albumin, thus delaying Cu uptake by the liver, (iii) depleting liver Cu, (iv) altering liver Cu and Cu from other tissues to a less available form, (v) increasing biliary Cu excretion, (vi) limiting reabsorption of biliary Cu, (vii) increasing urinary Cu excretion, and (viii) increasing endogenous secretion of Cu. Copper, S and/or Mo have also been identified as factors in the etiology of polioencephalomalcia and abmosal ulcers but the mechanisms involved are not clear. Key words: Ruminants, copper, defiency, metabolism, sulfur
ANIMAL AGRICULTURE RESEARCH AND DEVELOPMENT: CHALLENGES AND OPPORTUNITIES
Authors: BRADFORD ERIC
Published: March 2010

Livestock play a very important role in the agriculture of most developing countries, accounting on average for an estimated half of agricultural output through their direct and indirect contributions. Major functions include: production of human-edible food from human-inedible forages, crop residues and by-products; concentrating nutrients, thus increasing the quality of food and producing high-value products for sale; serving as a source of savings and income for producers who lack access to banks or credit; recycling plant nutrients and improving soil fertility; serving as a food reserve; and providing draft power. Crop-livestock systems are in general more stable and more productive than cropping systems alone. A perceived problem due to livestock is overgrazing and environmental degradation, but these are usually the result of human mismanagement of the animals. Traditional pastoral systems can be not only persistent, but ecologically sound. The currently observed problems associated with pastoral systems in arid and semi-arid lands are more likely to result from breakdown of traditional management practices due to human population increase and external intervention or social changes, or from abiotic factors such as climatic variation, than from flaws in the traditional system. Research and development programs can increase the contributions of animals to the well-being of their owners and to the economies of developing countries. Some areas with high potential include: evaluation of local genetic resources; assessment of feed resources and design of economical, efficient supplementation strategies; and reduction of costs of disease control by development of multivalent vaccines. There are opportunities for large increases in efficiency of resource utilization and animal productivity. However, a more thorough understanding of social and economic as well as biological aspects of production systems than has usually existed in development projects is essential for interventions, where they are indicated, to be effective. Key words: Food quality, efficiency, production systems, sustainability, genetic resources, animal traction
CARCASS CHARACTERISTICS OF YEARLING NORMAL AND DOUBLE MUSCLE CROSS BULLS
Authors: ARTHUR P. F. , MAKARECHIAN M. , PRICE M. A. , BERG R. T.
Published: March 2010

Data on 99 young bulls, which were the progeny of matings of either double muscle bulls and normal cows (DMx) or normal bulls and normal cows (N) born over three calving seasons, were analyzed to compare the carcass characteristics and lean yield of yearling DMx and N bulls. DMx carcasses had larger (P < 0.001) ribeye areas and cutability but smaller (P < 0.001) grade fat and average fat thicknesses than N carcasses, when the data were adjusted to either constant slaughter age (395.7 d) or constant carcass weight (304.7 kg). Muscle:fat and muscle:bone ratios and percent muscle in the 10th-11th-12th rib joint were higher (P < 0.001), while percent fat and percent bone in the rib joint were lower (P < 0.005) in DMx compared to N carcasses, when the data were adjusted to either constant grade fat thickness (10.0 mm) or constant rib joint weight (4871.4 g). The magnitude of the observed superiority of DMx over normal carcasses in lean yield was not the same across carcass grades. For A1 or A2 carcasses, rib joints from DMx carcasses had 8.8 and 5.7%, respectively, more (P < 0.05) muscle than those from N carcasses. Key words: Carcass characteristics, double muscle, crosses, cattle
CARCASS COMPOSITION OF STEERS GIVEN HAY, HAY SUPPLEMENTED WITH RUMINAL UNDEGRADABLE PROTEIN, OR CONCENTRATE
Authors: BAILEY C. B.
Published: March 2010

Holstein steers (10 per group) were given either 85% grass hay and 15% concentrate (group 1), the same diet with added rumen undegradable protein to raise the overall protein level from 120 to 130 g kg−1 (group 2), or 85% concentrate and 15% grass hay (group 3) until they were slaughtered at 500 kg. Extractable fat in separable muscle was greatest for steers in group 3, least for steers in group 2, and intermediate for those in group 1. Loin-eye area was less for steers in groups 1 and 2 than for those in group 3. Carcasses were a larger proportion of empty liveweight in steers in group 3 than in those in groups 1 and 2 due primarily to increased adipose tissue in the front quarter. In comparison with steers on a mainly hay diet, a hay diet supplemented with rumen undegradable protein did not affect the composition of the carcass although it increased the rate of gain from weaning to slaughter. Key words: Carcass, composition, nondegradable, protein, steer
APPARENT DIGESTIBILTY OF AMINO ACIDS AND OTHER NITROGENOUS COMPOUNDS IN THE SMALL INTESTINE OF WETHERS EXPOSED TO A COLD ENVIRONMENT
Authors: KELLY J. M. , CHRISTOPHERSON R. J. , EARLY R. J.
Published: March 2010

Digestion studies were conducted with eight shorn yearling Suffolk wethers to assess the effects of environmental temperature on intestinal digestion of nonammonia nitrogen (NAN) and amino acid N. The wethers were cannulated in the rumen, abomasum, and terminal ileum and subsequently chronically exposed to either cold (0–2 °C) or warm (21–25 °C) temperatures in a crossover experiment. Sheep were fed a diet of chopped bromegrass hay and digesta flows through the abomasum and terminal ileum were estimated by reference to 103ruthenium-phenanthroline and 51chromium-EDTA. Microbial N contributions to total N in abomasal digesta were estimated with 35sulphur. During cold exposure, mean rumen ammonia concentration was reduced (P < 0.01) by 20%, while net appearance of NAN across the forestomach increased from 2.7 to 7.3 g d−1 (P < 0.05) resulting in a 14% increase in flow of NAN from the abomasum. The latter was associated with a 63% increase in flow of undegraded feed N (P < 0.05) and a nonsignificant decrease in microbial NAN. There was a small increase in flow of most amino acids from the abomasum due to cold exposure, with significant effects for lysine, histidine and tyrosine (P < 0.05). Disappearances of lysine (P < 0.05) and tyrosine (P < 0.005) in the small intestine were increased by the cold environment. Cold exposure increased small intestinal digestion of amino acid N relative to digestible organic matter intake (P < 0.08) suggesting maintenance of amino acid supply relative to that of energy in a cold environment. Key words: Amino acids, digestion, small intestine, sheep, cold environment
THE EFFECT OF EXOGENOUS GROWTH HORMONE ON THE ENDOCRINE STATUS AND THE OCCURRENCE OF ESTRUS IN GILTS
Authors: KIRKWOOD R. N. , THACKER P. A. , GUEDO B. L. , LAARVELD B.
Published: March 2010

Fifty-six gilts of Yorkshire and Landrace breeding were selected at 86.8 ± 0.8 kg body weight (BW) and given an intramuscular (im) injection of 400 IU PMSG plus 200 IU hCG to stimulate ovulation. From 14 d after gonadotropic stimulation, gilts were exposed to a boar to detect a subsequent spontaneous estrus. At the onset of this first observed estrus, gilts were allocated to receive daily injections (i.m.) of growth hormone (pGH, 90 μg kg−1) from either 14 d (GH14, n = 21) or 17 d (GH17, n = 20) until 22 d after the onset of the first observed estrus. A third group of gilts served as controls (n = 15) and received vehicle buffer. Blood samples were obtained by jugular vein puncture at 3-d intervals from 14 to 29 d, inclusively. Gilts were slaughtered 30–32 d after the first observed estrus at which time their ovaries were recovered for the determination of ovulation rates. All control gilts and all but one GH17 gilt exhibited normal estrous cycles. However, of the 21 gilts assigned to GH14, only 9 (43%) had normal estrous cycles (P < 0.001). In gilts exhibiting a second estrus, there was no effect of pGH treatment on the duration of the estrous cycle (20.4, 20.9 and 20.5 d) or on ovulation rate (14.6, 13.9 and 13.5) for GH14, GH17 and controls, respectively. Serum assays revealed that pGH injections resulted in decreased serum concentrations of thyroxine (P < 0.01) but increased concentrations of triiodothyronine, insulin and glucose (P < 0.001). The present data confirm an adverse effect of pGH on ovarian function. However, the adverse effect is only evident when the pGH injection regime encompasses days 14–16 of the estrous cycle. Key words: Gilts, growth hormone, estrus, ovulation rate
EVALUATION OF BARLEY AND WHEAT HEAD-CHOP SILAGES FOR DAIRY COWS
Authors: BURGESS P. L. , MISENER G. C. , McQUEEN R. E. , NICHOLSON J. W. G.
Published: March 2010

Head-chop silages made from barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) harvested at the mid- to late-dough stage of maturity were evaluated by laboratory methods and by feeding to dairy cows. There were linear decreases in crude protein (CP) content and in vitro true digestibility (IVTD) when comparisons of grain, heads, heads + 15 cm straw, heads + 30 cm straw and heads + 45 cm straw were made. The barley and wheat head-chop silages produced for the cow feeding trial averaged 19.9 and 22.7% ADF and were readily accepted by the cows. The head-chop silages were fed at 22 kg cow−1 d−1 (as-fed basis) plus a grain mixture according to production level. The total grain consumption was similar to that of the control cows which were fed 1 kg of grain per 3 kg of milk produced. All cows were fed timothy (Phleum pratense L.) silage ad libitum. Cows fed the wheat head-chop consumed less total feed (P < 0.01) than those fed the other two treatments and produced less milk (P < 0.01); but, milk fat content was higher (P < 0.01) so there were no significant differences in fat corrected milk production among the treatments. It was concluded that head-chop silage was a suitable way of conserving cereal crops for feeding dairy cows. Key words: Barley, wheat, head-chop, dairy cows, silage
EFFECT OF SULPHUR DIOXIDE AND AMMONIA ON CHEMICAL COMPOSITION AND IN VITRO DIGESTIBILITY OF CORN STOVER AND BARLEY STRAW
Authors: INNOCENTI E. , MOWAT D. N. , MANDELL I. B.
Published: March 2010

The effects of temperature, treatment time and levels of SO2 and NH3 on the in vitro digestibility and chemical composition of corn stover and barley straw were evaluated. Sulphur dioxide improved (P > 0.05) in vitro dry matter digestibility (IVDMD) and in vitro cell wall digestibility (IVCWD) of corn stover when treated at 70 °C for 24 h. However, high SO2 levels (4 and 6%) at higher temperature (90 °C) and for a longer time (72 h) reduced (P < 0.05) IVDMD and IVCWD and increased (P < 0.05) lignin content. When barley straw was treated with SO2 at 70 °C, IVDMD and IVCWD were greater (P < 0.05) when the treatment was carried out for 72 h than for 24 h. The improvement in in vitro digestibilities with SO2 was associated with solubilization of large amounts of hemicellulose. Ammonia treatment at 70 °C for 24 h reduced (P < 0.05) hemicellulose content and increased (P < 0.05) IVDMD and IVCWD as well as apparent lignin content. Suphuration enhanced the effect of ammoniation on IVDMD and IVCWD and reduced lignin content, but did not further reduce hemicellulose over NH3 alone in both crop residues. Improvements in in vitro digestibilities obtained with NH3 treatment followed by SO2 were associated with reductions of hemicellulose and lignin. Sulphur dioxide and NH3 treatment at 70 °C for 24 h produced a greater improvement in IVDMD and IVCWD in barley straw than in corn stover. Treatment with SO2 following ammoniation further increased (P < 0.05) NH3-N and sulphur contents of corn stover. Key words: Chemical treatment, sulphur dioxide, ammonia, corn stover, barley straw, chemical composition, in vitro digestibility
USE OF THE IN SITU TECHNIQUE AND PASSAGE RATE CONSTANTS IN PREDICTING VOLUNTARY INTAKE AND APPARENT DIGESTIBILITY OF FORAGES BY STEERS
Authors: VON KEYSERLINGK MARINA A. G. , MATHISON G. W.
Published: March 2010

The in situ bag technique was evaluated as a method of predicting the voluntary intake and digestibility of forages. Nine feedstuffs including three cereal straws, three alfalfa (Medicago sativa L.) and grass hay mixtures, two alfalfa-grass silages, and a prairie (Festuca hallii L.) grass hay were each fed to five steers (350 ± 49.5 kg) at ad libitum and approximately maintenance feeding levels. Hays and silages were also fed at near the twice maintenance feeding level. Voluntary forage dry matter (DM) intakes ranged from 1.00 to 2.85% of body weight. Apparent forage DM digestibilities ranged from 37 to 64%. At the lower feeding level fractional rates of particulate passage through the digestive tract were higher (P < 0.05) for 37% DM silage (0.037 h−1) than for two of the straw-based diets (0.020–0.023 h−1). Particulate passage rates were not (P > 0.05) affected by feeding level. Predictions from in situ results were most accurate when 24 and 36 h degradation values were used to estimate DM digestibility (R2 = 0.92) and intake (R2 = 0.86), respectively. The neutral detergent fiber content of forage was equally well correlated with DM digestibility (R2 = 0.86) and voluntary DM intake (R2 = 0.85). Inclusion of information on rates of passage in prediction equations did not (P > 0.05) improve accuracies of predictions over those obtained using in situ results or chemical feed components. Key words: Steers, in situ, voluntary intake, digestibility, passage rates, prediction
ISOALDEHYDEDIUREAS AS NONPROTEIN NITROGEN SOURCES FOR RUMINANT ANIMALS
Authors: VON KEYSERLINGK MARINA A. G. , MATHISON G. W.
Published: March 2010

In experiments designed to evaluate isovaleridenediurea (IVDU; butanal, 3-methyl-di-urea) as a nonprotein nitrogen supplement for ruminant animals IVDU and isobutylidenediurea (IBDU; propanal, 2-methyl-di-urea) were compared to urea. Ammonia concentrations were increased (P < 0.05) by 2–5 mM when IBDU or IVDU were added to an in vitro incubation medium in comparison with up to 24 mM when equal amount of urea nitrogen was used. Isobutyric and isovaleric acid concentrations in the incubation medium were higher (P < 0.05) when IBDU and IVDU, respectively, were present. In an in vivo experiment, ammonia concentrations were reduced (P < 0.05) from 7.0 to 4.7 mM at 0.5 h after feeding when a mixture of 6 g IBDU and 6 g IVDU was substituted for 6.8 g urea in the diet of four sheep fed 1200 g hay and 100 g concentrate daily in a crossover experimental design. No differences (P > 0.05) in isobutyric or isovaleric acid concentrations in the rumen fluid were observed between treatments. Apparent digestibilities were not influenced by diet. It was concluded that although IVDU and IBDU had potential as nonprotein nitrogen supplements, degradation rates of both compounds were low and excessive amounts of the compounds may escape from the rumen undegraded. Key words: Sheep, isobutylidenediurea, isovaleridenediurea, nonprotein nitrogen supplements, in vitro, in vivo
EFFICACY OF ANHYDROUS AMMONIA AND SULFUR DIOXIDE AS PRESERVATIVES FOR HIGH-MOISTURE GRAIN AND THEIR EFFECT ON THE NUTRITIVE VALUE OF BARLEY FOR GROWING-FINISHING CATTLE
Authors: MATHISON G. W. , KENNELLY J. J. , ENGSTROM D. F. , ROTH L. , BECK B. E.
Published: March 2010

The effectiveness of ammonia and sulfur dioxide as preservatives for high-moisture barley grain and their influence on digestibility, rate and efficiency of gain, and the selenium and thiamin status of feedlot steers were examined. Duplicate 18-t plastic-bag bins were prepared with the following type and amount (wt/wt, dry matter (DM) basis) of preservative applied to low (23%) or high (32%) moisture barley: (1) high-moisture barley, no preservative (control); (2) high-moisture barley, 1.1% ammonia (1.1%-NH3); (3) high-moisture barley, 2.3% ammonia (2.3%-NH3); (4) low-moisture barley, 1.3% sulfur dioxide (1.3%-LMSO2); and (5) high-moisture barley, 1.7% sulfur dioxide (1.7%-SO2). Heating occurred in the control barley. Mold and yeast populations were substantially reduced in barley treated with ammonia which appeared well preserved. Considerable deterioration occurred in the core of one 1.3%-LMSO2 bin. Crude protein digestibility was lower (P < 0.001) for an all-concentrate diet containing 1.1%-NH3 barley fed whole (66.8%) than for three other diets containing rolled barley (mean 81.1%), although apparent digestibilities of other feed components were similar (P > 0.05). When the preserved grains were each fed to a group of 12 steers (363 kg initial weight) along with 1.0 kg hay daily, gains were 1.46, 1.72, 1.67, 1.33 and 1.31 kg d−1 (P < 0.05) for steers fed control, 1.1%-NH3, 2.3%-NH3, 1.3%-LMSO2, or 1.7%-SO2-treated barley, respectively. Corresponding kilograms of DM required per kilogram of grain were 6.11, 5.41, 5.53, 6.76, and 6.72 (P < 0.05). Serum selenium concentrations and thiamin status were similar (P > 0.05) for steers in all treatments at the end of the test. Key words: High-moisture barley, steers, preservatives, ammonia, sulfur dioxide
EFFECTS OF FEEDING FREQUENCY AND SOYBEAN MEAL SUPPLEMENTATION OF ALFALFA SILAGE ON DUODENAL NITROGEN SUPPLY TO SHEEP
Authors: RUIZ A. , MOWAT D. N. , GROVUM W. L.
Published: March 2010

Eight rams fitted with ruminal and duodenal cannulae were assigned to four treatments in an 8 × 4 crossover design. Treatments were a factorial combination of two feeding frequencies (1 × or 4 ×/d) and two diets fed at 2% of body weight (alfalfa silage with or without 10% soybean meal (SBM), dry matter basis). Diets were made isocaloric by the addition of corn. Supplementary SBM did not affect concentration of most rumen metabolites, except for increasing ammonia levels (P < 0.05). Rumen liquid kinetics were not affected by supplementation with SBM. However, SBM increased (P < 0.05) duodenal flow of microbial and residual N as well as efficiency of microbial protein synthesis when the diet was fed more frequently. Four times feeding increased the turnover rate of rumen liquid (P < 0.05). In addition, the diurnal variation of all rumen parameters was reduced, suggesting more stable rumen conditions and more uniform fermentation. Nevertheless, site and extent of organic matter and cell wall digestion were not affected. Nitrogen retention was improved (P < 0.05) with both diets due to 4 × feeding. Neither N flows to the duodenum nor efficiency of microbial protein synthesis were influenced when the control diet was fed frequently. Key words: Feeding frequency, soybean meal, alfalfa silage, duodenal nitrogen, rumen fermentation, sheep
THE INFLUENCE OF EGG WEIGHT LOSS DURING AND IMMEDIATELY FOLLOWING INCUBATION, AND DIETARY INTAKE OF ENERGY AND PROTEIN ON GROWTH AND FEED EFFICIENCY IN BROILER CHICKENS
Authors: SINCLAIR R. W. , ROBINSON F. E. , HARDIN R. T.
Published: March 2010

One thousand two hundred and seven eggs were obtained from a flock of 34-wk-old broiler breeders (Indian River strain). Prior to setting, eggs were weighed and sorted into groups of a common weight. Following hatching, the weight of the pooled hatch debris from each weight group was recorded. The percent weight loss (PWL) during incubation for each egg was calculated as follows:[Formula: see text]Chicks were sorted into two groups of 416 chicks each, based on PWL (high: 29.57% ± 0.31 and low: 24.32% ± 0.28). Chicks from each PWL group were fed one of four starter diets to 3 wk of age: (1) 26% crude protein (CP), 3200 kcal ME kg−1; (2) 23% CP, 2830 kcal ME kg−1; (3) 23% CP, 3200 kcal ME kg−1; and (4) 26% CP, 2830 kcal ME kg−1. From 3–6 wk of age all chicks were fed a 20% CP 3200 kcal ME kg−1 grower diet. Chicks in the low PWL treatments exhibited significantly higher body weights than high PWL chicks up to 5 wk of age. During the period from 1 to 3 wk, chicks fed the low-energy diet were heavier than chicks fed the high-energy diet. During the period from 1 to 6 wk, chicks fed the low-protein diet were significantly heavier than chicks fed the high-protein diet. The effects of energy and protein on body weight are attributed to significantly higher feed intake in the low-energy and low protein-fed birds. Key words: Broiler chicken, dietary energy, dietary protein, egg weight loss, incubation
AUTOMATIC WEIGHING OF POULTRY REARED ON A LITTER FLOOR
Authors: DOYLE IRENE , LEESON STEVE
Published: March 2010

Four trials were conducted to test the accuracy of an automatic weighing system with broiler chickens and turkeys. Body weights were recorded manually and automatically and compared statistically. The body weights obtained automatically were similar to body weights recorded manually (P > 0.05) with broilers weighing up to 2 kg and turkeys up to 2.5 kg. A larger plate size would be required to weigh heavier birds. The number of weights recorded per day varied according to age of bird. The sex of the bird, however, did not influence the number of weights recorded (P > 0.05). The automatic weighing system was shown to record a daily mean comparable to the mean obtained manually. Key words: Poultry, weighing, automation
NEAR INFRARED REFLECTANCE ANALYSIS OF FAT, PROTEIN AND GROSS ENERGY OF CHICKEN AND RAINBOW TROUT CARCASSES
Authors: VALDES E. V. , ATKINSON J. L. , LEESON S. , HILTON J. W.
Published: March 2010

Separate calibrations for fish and chicken carcasses were developed to predict chemical composition (percent crude protein and fat) and gross energy (GE) by near infrared reflectance analysis (NIRA). Percent crude protein (CP), percent fat and kJ g−1 of GE in the fish samples were predicted with standard error of the estimate (SEE) of 1.8, 1.4 and 1.7 respectively. The SEE values for the prediction of CP, percent fat and kJ g−1 of GE in chicken carcasses were 1.7, 2 and 0.54 respectively. Key words: Fish, chicken, carcass, NIRA, composition, energy
THE INFLUENCE OF ALLYL TRENBOLONE ON THE OCCURRENCE OF NORMAL ESTROUS CYCLES FOLLOWING A GONADOTROPHIN-INDUCED OVULATION IN PREPUBERTAL GILTS
Authors: VAN LUNEN T. A. , KIRKWOOD R. N. , THACKER P. A.
Published: March 2010

Sixty prepubertal Yorkshire × Landrace gilts were either injected with PMSG and hCG (n = 40) or acted as controls. Of the hormone-injected gilts, 20 were fed 15 mg d−1 of allyl trenbolone from 7 to 21 d after the PMSG injection. Gilts were mated at their second estrus. There was no effect of treatment on the incidence of cyclic estrous behavior or on subsequent ovulation rates and numbers of embryos. Key words: Allyl trenbolone, gonadotrophins, puberty, gilts
NALOXONE ELEVATES PLASMA FOLLICLE STIMULATING HORMONE BUT NOT LUTEINIZING HORMONE LEVELS IN THE IMMATURE MALE PIG
Authors: TRUDEAU V. , PHARAZYN A. , AHERNE F. X. , BELTRANENA E.
Published: March 2010

The effects of intraperitoneal injection of gonadotropin-releasing hormone (GnRH) alone, naloxone (NAL) alone, or in combination on plasma levels of follicle stimulating hormone (FSH) and luteinizing hormone (LH) was studied in 4- to 5-wk-old male pigs. GnRH (1 μg kg−1) effectively stimulated (P < 0.05) secretion of both gonadotropins whereas NAL (1 and 10 mg kg−1) stimulated only FSH secretion (P < 0.05). There was no interaction between GnRH and NAL on gonadotropin release. These results suggest that endogenous opiates are involved in the regulation of FSH secretion but not LH secretion in the immature male pig. Key words: Follicle-stimulating hormone, luteinizing hormone, naloxone, gonadotropin-releasing hormone, male pig
PREFERENCE AMONG DIFFERENT GRAINS EXPRESSED BY YOUNG HOLSTEIN CALVES
Authors: BUSH ROY S.
Published: March 2010

To assess whether young calves express a preference for the cereal component of their diet 24 calves from 3 to 17 wk of age were presented with a feed tray that contained a choice of four cereals — barley, wheat, corn and oats (exp. 1) and another group of 12 calves from 10 to 34 d of age were fed a choice of complete mixed calf starters based on barley, corn, oats and hull-less oats (exp. 2). The preference expressed by the calves was barley > wheat, corn or oats in exp. 1 and barley > hull-less oats or corn > oats by the end of exp. 2. Key words: Preference, grain consumption, barley, corn, oats
PLASMA TESTOSTERONE AND SHELL QUALITY
Authors: LEESON S. , BENNETT C. D. , CASTON L. J. , ANDERSON-LANGMUIR C. E. , ETCHES R. J.
Published: March 2010

Plasma testosterone levels were measured in commercial strain Leghorn pullets from 16 to 80 wk of age. Testosterone level was high just prior to first egg, but subsequently declined and stayed at a constant level through the production cycle. There was no relationship between testosterone concentration and eggshell quality (P > 0.05). Key words: Testosterone, shell quality
DISTRIBUTION OF CATTLE ON SLOPE WITHOUT WATER RESTRICTIONS
Authors: WILLMS W. D.
Published: March 2010

A study was made in the Porcupine Hills of southwestern Alberta to determine cattle distribution on slope when water is available at the top, middle, and bottom of the slope. Cows with calves were stocked at two rates (1.9 and 3.8 animal unit months (AUM) ha−1) and three replications over six small pastures in a completely random design. The study was repeated in each of 4 yr over a 3-wk period starting in mid-June of 1985. Average forage utilization over a 4-yr period was similar among slope positions (P > 0.05) and stocking rate had no effect on its distribution. However, forage utilization differed among slope positions within a grazing period. In 1985, measurements of individual plants showed that the distribution of use shifted from the top or middle position in the first 4 d of the trial to the bottom in the last 3 d. The higher stocking rate reduced position differences. Cattle obtained about 80% of total water consumed at the top or middle positions. This also represented the daytime proportion of cows observed at these sites. These observations suggest a diurnal preference for slope position because forage use was uniform among slope positions while daytime occupation of the middle and top positions was disproportionately high. Providing water only at top of slopes will synchronize the time cattle require water with daytime site preference. Key words: Cattle, feeding behavior, slope distribution, grazing, stocking rate
REPRODUCTIVE PERFORMANCE OF BOOROOLA × FINNISH LANDRACE AND BOOROOLA × SUFFOLK EWE LAMBS, HETEROZYGOUS FOR THE F GENE, AND GROWTH TRAITS OF THEIR THREE-WAY CROSS LAMBS
Authors: CASTONGUAY F. , MINVIELLE F. , DUFOUR J. J.
Published: March 2010

Reproductive performance of Booroola × Finnish Landrace (BFL, n = 19) and Booroola × Suffolk (BS, n = 18) ewe lambs heterozygous for the F gene were compared to Finnish Landrace (FL, n = 14) and Suffolk (S, n = 26) purebred controls. FL lambs reached puberty earlier (211.3 d, P < 0.001) than the other genetic groups (237.8, 233.0 and 232.9 d for S, BS and BFL, respectively) whereas weight at puberty was lower (P < 0.001) for BFL, FL and BS (36.8, 36.7 and 47.0 kg, respectively) than for S (61.1 kg). About 95% of BFL and BS ewe lambs had at least one record of three ovulations or more over the first three estruses, including puberty. Mean ovulation rates at breeding (second estrus after puberty) to a Hampshire (H) ram were 3.8, 3.3, 2.2 and 1.7 for BFL, BS, FL and S, respectively (BFL and BS vs. FL and S, P < 0.001). The corresponding litter sizes at birth were 2.5, 2.1, 1.6 and 1.3 (BFL and BS vs. FL and S, P < 0.001) which reflected a higher embryonic loss in the Booroola crosses. Percentage ova loss ranged between 32.8% (BFL) and 12.8% (S) and was related to the level of prolificacy. Lamb mortality at birth was high in BFL (23.7%) compared to BS, FL and S (6.5, 0.0 and 0.0%, respectively, P < 0.001). Litter size at weaning (50 d of age) averaged 1.9, 1.8, 1.5 and 1.3 for BS, BFL, FL and S ewe lambs (BS vs. S, P < 0.02). Growth performance of H-sired progeny from the four genetic groups of ewes showed that H × S lambs had the highest average daily gain in both preweaning and postweaning periods (preweaning ADG: 349.9 g d−1; postweaning ADG: 332.1 g d−1) while the other genotypes of lambs performed equally (preweaning ADG: 267.4, 249.5 and 246.8 g d−1 for H × FL, H × BFL and H × BS, respectively; postweaning ADG: 281.2, 276.8 and 281.8 g d−1 for the same genetic groups). Overall productivity of ewe lambs in terms of kilograms of lamb produced showed a slight, nonsignificant, advantage for Booroola-cross ewe lambs (55.8 and 54.5 kg for BS and BFL) over purebred S (51.6 kg) and FL (44.9 kg). These results indicate that ovulation rate and litter size can be increased by incorporating F gene in both prolific (FL) and nonprolific (S) background genotypes without resulting in any significant difference in total weight of lamb produced per ewe. Key words: Sheep, ewe productivity, Booroola, ovulation rate, crossbreeding
ESTIMATION OF THE FREQUENCY OF THE HALOTHANE GENE AND ITS EFFECTS IN LANDRACE AND YORKSHIRE PIGS IN ONTARIO
Authors: HUBBARD D. J. , SOUTHWOOD O. I. , KENNEDY B. W.
Published: March 2010

Data from 2554 Landrace and 2566 Yorkshire young boars submitted to the Record of Performance test station in Ontario between 1982 and 1986 were used to estimate frequency of reaction to halothane and frequency of the halothane gene. Approximately 1.4% of Landrace and 0.9% of Yorkshire boars had a positive reaction to halothane. The number of reactors detected at the test station declined with time, particularly in the Landrace. There was evidence of the presence of the halothane gene in 25 Landrace and 25 Yorkshire breeder herds and 5.8% of Landrace and 2.8% of Yorkshire sires had progeny which tested positive. Maximum likelihood estimates of frequency of the halothane gene were 0.10 ±.02 in Landrace and 0.09 ±.02 in Yorkshire. There was only weak selection against sire lines known to have had reactor progeny. Based on estimated breeding values, sires and dams that had reactor progeny were genetically leaner than contemporaries, but there was no consistent, or significant relationship with days to 90 kg. Key words: Halothane gene, frequency, selection, swine
THE EFFECT OF LOAD CARRYING ON CARCASS CHARACTERISTICS AND COMPOSITION IN SHEEP
Authors: AALHUS J. L. , PRICE M. A.
Published: March 2010

Two experiments were conducted to investigate the effects of load carrying on muscle growth and development in sheep under conditions of restricted (exp. 1) and free choice (exp. 2) feeding. In exp. 1, the load-carrying sheep ate as much feed as their control counterparts to maintain a constant liveweight. There was no increase in total muscle mass in load-carrying sheep, although there were small shifts in muscle distribution. The proportion of muscle in the proximal thoracic limb appeared higher in load-carrying than in control sheep (15.2 vs. 13.3%; P = 0.07). In addition, bone weights in the thoracic limb were heavier in load-carrying than in control sheep. The changes in bone and muscle distribution ate assumed to be a direct response to increased load bearing. In exp. 2, load-carrying sheep are less feed and grew more slowly than their control counterparts. The only change directly attributable to the load-carrying exercise was an alteration in shape of the metacarpal bone. Key words: Sheep, load-carrying exercise, carcass composition, tissue distribution
INFLUENCE OF SEASON AND SOCIAL ENVIRONMENT ON THE REPRODUCTIVE-ENDOCRINE STATUS OF THE ADULT LANDRACE BOAR
Authors: TRUDEAU V. L. , SANFORD L. M.
Published: March 2010

Seasonal variations in LH, FSH, and testosterone secretion were investigated for adult Landrace boars housed in different social environments for 1 yr. Socially nonrestricted boars (n = 4) were penned adjacent to ovariectomized gilts that were hormonally brought into estrus every 2 wk, while socially restricted boars (n = 4) were kept in pens with solid walls. Mean hormone concentrations were determined from the assay of single AM and PM blood samples collected from the jugular vein by venipuncture once a month. In November, February, May and August, blood samples were collected serially over 12 h from jugular catheters for assessment of pulsatile LH and testosterone secretion, and the LH response to a GnRH injection (1 μg kg−1 body weight). Mean LH and testosterone concentrations were relatively high in all boars during the late summer and fall, and often were greater for the socially nonrestricted versus the restricted boars (group × month), P < 0.05) in the winter (December and January). Mean FSH concentration also varied with month (P < 0.05). Pulse analysis indicated that higher mean testosterone concentrations in November and August were the result of increases (month, P < 0.05) in testosterone-pulse frequency and basal concentration. Maximal mean LH concentration in August was associated with maximal (month, P < 0.05) LH-pulse amplitude and basal concentration. The amplitude of the LH peak following GnRH injection increased (P < 0.05) between November and May, and remained high in August. Key words: Gonadotropins, testosterone, blood, season, social environment, boar
EFFECTS OF UTERINE INFUSION OF NONVIABLE SEMEN, SEMINAL PLASMA OR EGG ALBUMEN PRIOR TO BREEDING ON THE REPRODUCTIVE EFFICIENCY OF GILTS OR SOWS
Authors: GILES J. R. , THOMPSON L. H. , ARKINS S. , CAMACHO T. , EICHEN P. A.
Published: March 2010

In two different experiments crossbred gilts and(or) sows were used to investigate the effects of uterine exposure (prior to breeding) to nonviable semen (NS), seminal plasma (SP) or egg albumen (EA) on reproductive performance. Treatment solutions were infused via the cervix at estrus in gilts or within 2 d post-partum in sows. Females were artificially inseminated at the subsequent estrus. In the first experiment pregnancy rates for gilts infused with Beltsville Thawing Solution (BTS) as controls, NS or EA and subsequently inseminated, were 76, 85 and 54%, respectively, and were not significantly different among treatment groups. The number of total embryos (adjusted for number of corpora lutea) present at 38 d postinsemination was 9.6, 9.0 and 9.6, respectively, for BTS, ND and EA infused gilts and was not significantly different. Likewise, the number of live and dead embryos was not different among treatments. In the second experiment, the proportions of inseminated sows infused with BTS, NS or SP that subsequently farrowed were 87, 84 and 92%, respectively, and did not differ significantly among treatments. No significant differences were detected for the number of total, live or dead pigs born per litter among treatments. We conclude that uterine exposure to seminal proteins or egg albumen prior to breeding does not alter reproductive performance in gilts by 38 d of gestation. Also, the infusion of seminal proteins in sows shortly after parturition does not affect pregnancy rates or litter size at the subsequent farrowing. Key words: Reproductive efficiency, litter size, swine, artificial insemination
EFFECT OF GROWTH HORMONE-RELEASING FACTOR AND(OR) THYROTROPIN-RELEASING FACTOR ON HORMONE CONCENTRATIONS AND MILK PRODUCTION IN DAIRY COWS
Authors: LAPIERRE H. , PETITCLERC D. , PELLETIER G. , DELORME L. , DUBREUIL P. , MORISSET J. , GAUDREAU P. , COUTURE Y. , BRAZEAU P.
Published: March 2010

In a 2 × 2 factorial design, 32 cows (n = 8 per treatment) averaging 196 d of lactation received, for 10 consecutive days, daily subcutaneous injections of saline (group 1), human growth hormone-releasing factor (1-29)NH2 (GRF, 10 μg kg−1 BW; group 2), thyrotropin-releasing factor (TRF, 1 μg kg−1 BW; group 3), or GRF (10 μg kg−1 BW) plus TRF (1 μg kg−1 BW; group 4). Blood was collected from 24 cows (n = 6 per treatment) on the first and last day of injection. The synergistic action of the two hypothalamic factors on growth hormone (GH) release was maintained throughout the experiment (P < 0.05). Prolactin (Prl) concentrations increased (P < 0.01) after TRF administration on both sampling days. There was no interaction between the two peptides on thyrotropin (TSH) and thyroxine (T4) concentrations. TSH response to TRF (P < 0.01) observed on the first day was not detectable (P > 0.10) on the 10th day of injection and the TRF-induced T4 response decreased (P < 0.05) from day 1 to day 10. GRF treatment increased (P = 0.06) insulin-like growth factor-I concentrations while TRF had no effect (P > 0.10). Milk production and composition and feed intake were recorded from 10 d before to 10 d after the injection period. Data were averaged for the last 5 d of each 10-d period. Milk production during the injection period averaged 18.8, 20.6, 20.7, and 22.3 kg d−1 for groups 1–4, respectively. Effects of GRF and TRF were additive. Treatment with TRF did not change milk composition but GRF treatment decreased milk protein content. Feed intake did not differ (P > 0.10) between treatments. In summary, the synergy between GRF and TRF on GH concentration was sustained through a 10-d treatment period. Despite this synergy, GRF and TRF had only an additive effect on milk production. Further investigation is needed to confirm whether this successful combination of these two hypothalamic factors can be used on a Song-term basis. Key words: GRF, TRF, milk production, hormone, insulin-like growth factor-1, cows (dairy)
SODIUM AND POTASSIUM CONCENTRATIONS IN RUMINAL CONTENTS AFTER FEEDING BLOAT-INDUCING ALFALFA TO CATTLE
Authors: MAJAK W. , HALL J. W.
Published: March 2010

Postprandial fluctuation of ruminal cations was determined in cattle with different susceptibilities to alfalfa bloat. Rumen contents were sampled before feeding and at regular intervals after feeding fresh alfalfa to determine the changes in concentration of sodium (Na) and potassium (K). Levels of Na and K changed dramatically 1.5–2.5 h after feeding. When compared to prefeeding levels, Na concentrations were lower but K concentrations were higher immediately after feeding fresh alfalfa. When rates of change of the ion concentrations were examined during the 8-h postprandial period, differences among animals were not detected (P > 0.05). Sodium levels in ruminal contents consistently increased after feeding and K levels decreased to prefeeding levels. However, bloat-prone animals had lower average Na but higher K concentrations than the less susceptible animals. The resultant shift in the ionic equilibria may contribute to the occurrence of bloat through colloidal aggregation of chloroplast particles. Key words: Legume, bloat, alfalfa, cattle, rumen cation concentrations
ARTICULAR CARTILAGE CONDITION SCORE OF DISTAL HUMERUS AND FEMUR OF SWINE AS INFLUENCED BY DIETARY Ca-P LEVELS, SEX AND AGE
Authors: KORNEGAY E. T. , COMBS N. R. , VEIT H. P. , LINDEMANN M. D.
Published: March 2010

Crossbred barrows and gilts (n = 434) were fed 70, 85, 100, 115 or 130% of NRC Ca-P recommendations from 10 to 105 kg to evaluate the influence of Ca-P levels, sex, and age on the subjective condition score of the articular cartilage of the distal humerus and distal femur. The frequency and severity of lesions increased over time and was similar among sexes. After 140 d on test (105 kg BW), fewer articular cartilage lesions were observed on the distal femur compared with the distal humerus (15 vs. 71%, respectively). Dietary Ca-P levels did not influence the development of these lesions. Key words: Articular cartilage, femur, humerus, swine, calcium, phosphorus
A SIMULTANEOUS EQUATIONS MODEL OF THE CAUSE-EFFECT RELATIONSHIPS AMONG BIOLOGICAL VARIABLES: AN ANALYSIS USING POSTPARTUM BEEF COWS
Authors: GREER R. C. , SHORT R. E. , BELLOWS R. A.
Published: March 2010

A path diagram, as the basic model of a biological system, was used to explore the possible relationships generating observed correlations among physiological and body-trait responses in beef cows. The implications for statistical model specification and estimation were discussed. The model specified was a simultaneous system of equations with the physiological and body-trait responses constituting the set of endogenous variables; length of postpartum anestrous interval (PPI) was chosen as the physiological response of primary interest. The set of predetermined variables representing basic determinants of the biological system included plane of nutrition and obstetrical assistance experiments. From the generalized least-squares parameter estimates it was concluded that basic determinants in common explained much of the correlation among observed values of the physiological and body-trait responses. The cause-effect relationships included a recursive dependency of PPI upon postpartum body condition score and parturition date. In addition, it was concluded from the results that management decisions and events before the experimental period were more important in explaining variation in PPI than were the experimental treatments. Leading to the further conclusion that ignoring or attempting to randomize over such influences in the experimental design may jeopardize experimental results. The system of equations approach to analysis of biological data makes clear the importance of completely thinking through the problem before the experiment, the limitations of ordinary least-squares procedures and should have applications in other biological systems. Key words: Simultaneous equations analysis, anestrus, beef cows, body condition, return interval
STEROIDES MUSCULAIRES ET QUALITÉ DE LA VIANDE DE BOUVILLONS ET DE TAURILLONS
Authors: GARIÉPY C. , AMIOT J. , BÉLANGER A. , FLIPOT P. M. , GIRARD V.
Published: March 2010

We evaluated meat quality and testosterone and cortisol contents of meat from 30 bulls and 30 steers. Meat from steers had significantly higher fat content, lower total collagen, pH, shear forces and L, a and b values than meat from bulls. Sarcomere length, soluble collagen, and steroids content were not statistically different between bulls and steers. No direct hormonal effects on meat quality have been found. Reported differences in meat quality could be attributable to stress and slaughter ages. Key words: Steroids, meat quality, bulls, steers
THE INFLUENCE OF EXOGENOUS GROWTH HORMONE ON ENDOCRINE STATUS AND THE OVULATORY RESPONSE TO PMSG IN PREPUBERTAL GILTS
Authors: KIRKWOOD R. N. , THACKER P. A. , KORCHINSKI R. S. , LAARVELD B.
Published: March 2010

Twenty-three prepubertal Yorkshire × Landrace gilts were allocated to receive daily injections of either porcine growth hormone (pGH) or vehicle for 6 consecutive days. At the time of first pGH or buffer injection, all gilts received an injection of 500 IU PMSG. Blood samples were taken by jugular vein puncture at 0, 24 and 48 h then every 12 h until 96 h then every 8 h until 144 h. Samples were assayed for triiodothyronine (T3), insulin, glucose and LH. Treatment with pGH elevated (P < 0.01) serum concentrations of T3, insulin and glucose, and was associated with a reduced (P < 0.05) LH surge height. Fewer pGH-treated than vehicle-treated gilts ovulated (4/12 vs. 7/11), but the difference was not significant. Key words: Gilts, growth hormone, gonadotrophins, ovulation
EFFECTS OF DIETARY MOLYBDENUM ON RUMEN DRY MATTER DISAPPEARANCE IN CATTLE
Authors: SHARIFF M. A. , BOILA R. J. , WITTENBERG K. M.
Published: March 2010

The effects of Mo upon in situ dry matter (DM) disappearance of roughages and grains were examined in steers. Supplemental Mo had negative effects on the DM disappearance of grains in cattle fed a high-grain diet and positive effects on the DM disappearance of roughages and corn grain in steers fed a high roughage diet. Key words: Molybdenum, dry matter disappearance, cattle
REGRESSION ESTIMATES OF LYSINE AND OTHER AMINO ACIDS IN MANITOBA BARLEY
Authors: DUPCHAK K. M. , HICKLING D.
Published: March 2010

Manitoba barley samples from the 1986 and 1987 crop years were analyzed for lysine and crude protein. The 1987 samples were also analyzed for other amino acids and for proximate components. Regression equations were developed to predict amino acid content. Crude protein was found to be a good predictor of amino acid levels. There was no effect of crop year on the prediction equation for lysine. Key words: Barley, lysine, prediction
RATES OF INBREEDING IN YORKSHIRE, LANDRACE, DUROC AND HAMPSHIRE PERFORMANCE TESTED PIGS IN ONTARIO
Authors: HUBBARD D. J. , SOUTHWOOD O. I. , KENNEDY B. W.
Published: March 2010

Coefficients of inbreeding accumulated over a 10-yr period were computed for 140 376 Yorkshire, 89 673 Landrace, 29 776 Duroc and 21 873 Hampshire pigs performance tested on the Canadian Swine Improvement Program in Ontario between 1977 and 1987. All tested pigs were identified as to sire and dam. When all pigs were considered, both inbred and non-inbred, average inbreeding levels were less than 1%. Among inbred pigs, average levels were 4.5–8.8%, depending upon breed. The maximum inbreeding coefficient was 37.5%. Although average inbreeding levels were low, some herds had average inbreeding levels as high as 14%. Linear rates of increase in inbreeding coefficient ranged from 0.10 to 0.13% per year. However, rates of increase were non linear in all breeds, and by 1987 all breeds had average inbreeding coefficients of only slightly more than 0.8%. By 1987, 29, 19, 17 and 13% of Yorkshire, Landrace, Duroc and Hampshire pigs, respectively, were inbred to some degree. The rate of increase in proportion of inbred pigs was generally linear. Implications with respect to genetic evaluation and selection are discussed. Key words: Inbreeding coefficients, performance test, Yorkshire, Landrace, Duroc, Hampshire