bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of PMSG antiserum on serum progesterone and estrous cycles of PMSG-treated gilts
Authors: Kirkwood R. N. , Thacker P. A.
Published: March 2010

Forty-seven prepubertal gilts (88.4 ± 0.9 kg) received an injection of 750 IU PMSG to stimulate ovarian activity. After 96 h, 23 gilts received an injection of an anti-PMSG serum. Blood samples were obtained at the time of PMSG injection (day 0) and at 2, 4, 6, 11, 18, 25 and 32 d. There was no effect of treatment on serum estradiol concentrations or on the occurrence of normal estrous cycles. However, luteal phase serum progesterone concentrations were higher (P < 0.01) in gilts receiving the anti-PMSG. Key words: PMSG, antiserum, gilts, ovulation
Use of triticale silage in diets for growing steers
Authors: ZoBell D. R. , Goonewardene L. A. , Engstrom D. F.
Published: March 2010

A total of 120 steers were fed either barley silage (BS) or triticale silage (TS) combined with barley (B) or high-moisture barley (HMB) grain, as a total mixed ration in a 2 × 2 factorial design with three replications. The barley and triticale yields were 9.8 and 8.7 t ha−1, respectively. No differences (P > 0.05) in weight, average daily gain, dry matter intake or feed efficiency were observed for treatments or interactions. TS can be used to replace BS at moderate levels in growing steer rations containing barley grain. Key words: Barley, triticale, silage, steers, performance
Utilization of methionine isomers and analogs by the pig
Authors: Chung T. K. , Baker D. H.
Published: March 2010

A total of 72 pigs averaging 9.6 ± 1.4 kg were used to evaluate the efficacy of supplemental L-methionine (Met), D-Met, DL-Met and DL-methionine hydroxy analog free acid (DL-HMB) when added to a Met-deficient feather meal-corn-soybean meal-dried whey diet. Growth performance was similar for all diets containing isomolar levels of Met isomers and analogs, and the pigs utilized L-Met, D-Met, DL-Met and DL-HMB with the same molar efficiency. Key words: Pigs, methionine isomers and analogs, growth performance
A vortex vacuum evaporator for samples in test tubes
Authors: Dugan Michael E. R. , Sauer W. C. , Fenton T. W.
Published: March 2010

A vortex vacuum evaporator is described for the rapid and inexpensive evaporation of small liquid volumes from samples in test tubes. The evaporator, compared to other practical alternatives, appears only limited by its high labour requirement and thus would prove useful where limited numbers of samples are involved, or where labour input is not a factor. Key words: Vortex, water jacket, vacuum, evaporator, liquid
The preferences of hens for compact fluorescent over incandescent lighting
Authors: Widowski Tina M. , Keeling Linda J. , Duncan Ian J. H.
Published: March 2010

To determine whether laying hens find the flicker of fluorescent light aversive, their preferences were tested individually in a two-room testing chamber in which each room could be illuminated by either incandescent or fluorescent lights. The rooms were joined by a central compartment which acted as a light baffle and through which the birds could easily pass. The level of illumination in the two rooms was carefully matched and other resources such as food, water and nest-boxes were available in both rooms. The preferences of 16 mature light hybrid hens which had experience of both fluorescent and incandescent lighting were recorded during a 6-h test period on each of 2 d with the light sources in the rooms being switched on the second day. Overhead video cameras recorded the position and the behaviour of the birds throughout testing. On each of the test days, the hens spent significantly more time in fluorescent light than they did in incandescent light (each day: P < 0.01). When data from both test days were combined, the birds spent on average 73.2% of their time under fluorescent light and only 26.8% under incandescent (P < 0.001). Frequency distributions of ingestive behaviour, nesting, preening, resting and walking indicated that the birds performed all activities in both rooms and in both types of light. These results indicate that the birds either did not perceive the flicker of the fluorescent lights or perceived the flicker and did not find it aversive, and that they found some aspect of the fluorescent light more attractive than incandescent. Key words: Lighting, fluorescent, incandescent, behaviour, poultry
Genetic line × concentrate level interactions for milk production and feed efficiency in dairy cattle
Authors: Wang S. , Roy G. L. , Lee A. J. , McAllister A. J. , Batra T. R. , Lin C. Y. , Vesely J. A. , Wauthy J.-M. , Winter K. A.
Published: March 2010

Early first lactation data from 2230 cows of five research herds of Agriculture Canada were used to study the interactions of genetic line by concentrate level, and sire by concentrate level and to estimate breeding values of sires. The genetic lines were defined as Holstein (H), Ayrshire (A), and H × A or A × H (C). The interactions of sire by concentrate level were studied separately using progeny of five different mating groups: G1, H sires mated to H cows; G2, H sires mated to H, A and C cows; G3, A sires mated to A cows; G4, A sires mated to H, A and C cows; and G5, C sires mated to C cows. The interactions of genetic line by concentrate were significant (P < 0.05) for 56- to 112-d milk yield (MY112), corrected 56-to 112-d milk yield (CMY112) and feed efficiency (EFMY112 = MY112/TDN consumption). H and C cows produced more milk and were more efficient than A cows when fed high levels of concentrate. The H cattle possess a greater capacity to convert the concentrate into milk, while A cattle reach maximum milk production earlier than H cattle. The interactions of sire by concentrate were statistically significant for MY112, EFMY112 and CMY112 in G1 (P < 0.01), and G2 (P < 0.01). The breeding values of sires for MY112 were estimated using BLUP for all of the H line (BLUP-T), for half of the population consuming low amounts of concentrate (BLUP-L) and for the other half consuming high amounts (BLUP-H). A significant reranking of sires was found among the three groups. Key words: Genotype × environment interaction, milk production, efficiency, breeding value, dairy cattle
Estimation of lamb carcass composition using an electronic probe, a visual scoring system and carcass measurements
Authors: Jones S. D. M. , Jeremiah L. E. , Tong A. K. W. , Robertson W. M. , Gibson L. L.
Published: March 2010

Sixteen hundred and sixty lambs were used to determine the precision of carcass measurements (fat thickness, muscle thickness, tissue depth) and a visual scoring system for muscle and fat thickness to estimate carcass composition. Measurements of fat (F) and muscle (M) thickness were made in warm and cold carcasses and total tissue depth in warm carcasses only between the 10th and 11th ribs and the 12th and 13th ribs using an electronic probe (Hennessy Grading Probe HGP). F explained 40–64% of the variation in carcass lean and 44–72% of the variation in carcass fat depending on the location and number of measurements and whether they were made on a warm or cold carcass. In most cases when M was added to F there was no increase in the variation explained in composition over that provided by F alone. Total tissue depth measurements differed in precision for the prediction of carcass lean content with the 12th rib being superior to the 10th rib (RSD for 12th rib, 33.2 g kg−1; 10th rib, 36.6 g kg−1). Visual assessment of carcasses for fatness had the lowest precision for the prediction of lean content (RSD, 44.5 g kg−1). Loin eye area and fat thickness measured at the 12th rib had similar precision for the estimation of lean content as probe measurements. It was concluded that probe measurements of F or tissue depth between the 12th and 13th ribs would provide a superior method to the visual assessment of carcass fatness used in this study for classifying lamb carcasses for lean content and would allow carcasses to be graded on the slaughter floor. Key words: Lamb, carcass, grading, Hennessy Grading Probe, composition
Application of 13CO2 measurements to the estimation of energy expenditure in goats
Authors: Sahlu T. , Jacquemet N. , Carneiro H. , Hart S. P. , Klein P. D.
Published: March 2010

The use and limitations of 13C stable isotopes as tracers in animal experimentation was investigated using 13C-labeled bicarbonate to estimate CO2 production and energetic requirement of free-ranging goats. Goats were fed wheat hay (Triticum aestivum; C3) or Old World Bluestem hay (Bothriochloa caucasica; C4; OWBS) ad libitum for 21 d. Parotid salivary ducts were cannulated for saliva collection. Isotopic bicarbonate (13C) was infused at a constant rate into the peritoneal cavity. In exp. 1, saliva samples were obtained at successive 2-h periods for 20 h to establish the time to achieve equilibrium. The half-life of bicarbonate was 2.9 h for animals consuming the wheat diet and 4.1 h (P < 0.06) for animals consuming OWBS diet. The time required to reach equilibrium was 12 h for animals on the wheat diet and 16 h for animals on OWBS diet. The error in the technique arising from animals consuming C3 vs. C4 species (which have different endogenous 13C contents) was studied in exp. 2. If species composition (C3 vs. C4) of the diet remains constant within 10%, the error is negligible. In exp. 3, estimation of CO2 production from continuous saliva samples had a lower coefficient of variation (6.3 vs. 10.0%) than measurements based on spot serum samples. Energy expenditure of goats in stalls consuming hay ad libitum was similar to that of ad-libitum-fed sheep at similar body weights. The 13C methodology appears to be a promising method for measuring energy expenditure of grazing animals. Key words: Energy requirement, stable isotopes, carbon dioxide, sodium bicarbonate
Effect of ammoniation and urea addition on chemical composition and digestibility of mature timothy hay, and rumen fluid characteristics of growing steers
Authors: Chiquette J. , Flipot P. M. , Vinet C. M.
Published: March 2010

Feed quality of timothy (Phleum pratense L.) harvested at the beginning of heading (H), with a crude protein (CP) content of 13.3%, was compared to timothy harvested at a late stage of growth either untreated (M) or treated with anhydrous ammonia (30 g kg−1 dry weight) (MA); or with urea added at feeding (MU) making it isonitrogenous with MA. These diets were fed to eight ruminally fistulated steers (220 ± 12 kg) in a 4 × 4 double Latin square. Treatments MA and MU increased the crude protein (CP) content of timothy from 8.3 (M) to 19.8 and 21.8%, respectively. Ammoniation improved the apparent digestibility of dry matter (DM) (68 vs. 62%), CP (66 vs. 47%), hemicellulose (HC) (85 vs. 67%), and cellulose (C) (79 vs. 65%), compared to M. In support, in sacco DM disappearance was about 18% units greater (P < 0.01) for ammoniated hay (MA) as compared with M. Ammoniated timothy hay had apparent digestibility of DM, CP and C (68, 66 and 79%, respectively) similar to that of timothy hay from early harvest (67, 65 and 75%, respectively) and greater HC digestibility (85%) than that of all other hays (77, 67 and 66% for H, M and MU, respectively). Except for CP, digestibility of the other constituents was greater following ammonia treatment than following urea application. Soluble protein was significantly higher in rumen fluid of steers fed MA compared to other treatments. Ammoniation increased energy released from structural carbohydrates, made available following the delignification process, which resulted in improved overall DM digestibility. Ammoniation compensated for deterioration caused by late harvest, resulting in forage constituent digestibility comparable to that of early harvested hay, while additional nitrogen (N) brought about by MU did not improve the overall digestibility of the forage. Ammoniation appears to be an efficient means of increasing N and structural carbohydrate digestibility of low-quality timothy forage. Key words: Ammoniation, urea addition, Phleum pratense L., digestion, rumen fluid
Performance of growing steers fed quackgrass hay supplemented with canola meal
Authors: Seoane J. R. , Christen A.-M. , Fontecilla J. , Veira D. M.
Published: March 2010

Sixteen large-frame crossbred beef steers (282 ± 5.5 kg) were used to determine the effect of canola meal (CM) supplementation on voluntary intake, average daily gains (ADG) and digestibility in growing cattle fed quackgrass (Agropyron repens) hay harvested at early heading. All animals received the hay ad libitum during the 81-d experiment. Seven steers received a supplement of 400 g (as fed) of CM per head daily. Average daily gains were 60% higher for steers receiving CM supplementation compared to those receiving only hay (0.93 vs. 0.58 kg, respectively, P < 0.001). Canola meal supplementation tended to improve hay intake by 8% (P = 0.06) when expressed in terms of g kg−0.75. Feed efficiency was 37.6% higher following CM supplementation (P < 0.001). Apparent DM and energy digestibilities were not different between diets, but protein digestibility was 2.9% higher for steers receiving CM (P < 0.01). On the other hand, apparent digestibilities of fibre components were lower in steers receiving CM (2.7% for neutral detergent fibre, P < 0.05, and 6.4% for acid detergent fibre, P < 0.001). Digestible energy of the total diets was only slightly higher for the one supplemented with CM (P = 0.10). The increase in ADG observed was partially explained by the increase in voluntary intake of the diet following CM supplementation. Key words: Canola meal, quackgrass hay, cattle, growth
Effect of moisture level on ensiling characteristics of alfalfa in big bales or chopped and compacted in plastic tubes
Authors: Nicholson J. W. G. , Charmley E. , Bush R. S.
Published: March 2010

Alfalfa was ensiled at 270 (wet) or 400 (control) g DM kg−1 as long forage in plastic-wrapped big round bales (bale) or chopped (1.25 cm) and compacted (bag). The pH of the bag silages were lower (P < 0.01) throughout the 60-d observation period and stabilized at 4.7 ± 0.1 by day 3. The pH of the bale silages fell gradually to 5.5 by day 60. Lactic acid content was initially higher (P < 0.01) in the bag silages but by day 10 it was similar in the two types of silage. Acetic acid contents also were higher (P < 0.01) in bag than in bale silages and in wet than in control at day 1 and these differences persisted through day 60. Protein degradation was extensive in all silages as indicated by NH3-N and non-protein N contents at day 60 but it was more extensive in bale than in bag (P < 0.01) and in wet than in control (P < 0.05) silages. Lactobacilli counts were higher (P < 0.05) in bag than in bale silages at day 3 but the differences did not persist. Yeast and Clostridia counts and butyric acid contents were higher in bale than in bag silages in later stages of fermentation. None of the silages was well preserved, probably because of the low water-soluble carbohydrate content of the forage, but all were well accepted by sheep. Digestibility of the ADF fraction was higher (P < 0.05) for bale than for bag silages. Key words: Big bale, silage, ensiling characteristics, moisture level, bagged silage
Forage intake and grazing times of yearling beef steers grazing nitrogen-fertilized Russian wildrye (Psathyrostachys junceus)
Authors: Holt N. W.
Published: March 2010

Forage dry matter intake of yearling steers from nitrogen- (N) fertilized Russian wildrye (Psathyrostachys junceus) pastures was determined by an external indicator technique on five occasions during the summers of 1986 and 1987 at Swift Current, Saskatachewan. The N fertility levels were: 55 kg ha−1 N and 110 kg ha−1 N (the sum of available N and annually applied N fertilizer) and an unfertilized control (15 kg ha−1 available nitrate-N). Forage dry matter intake by steers (290 kg at turn out in May) was 1.5% of steer body weight (BW) when forage dry matter digestibility (DMD) was 48% and averaged 2.3% of steer BW when DMD was 54–62%. Forage dry matter intake was indirectly related to the N fertility level of the pasture by the positive effect of N fertilizer level on forage DMD. Fecal output, as determined by chromic oxide dilution, varied from 0.86% of BW in August 1986 to 1.12% of BW in July 1987. There was no relationship of fecal output to the N fertility of the grazed pasture. Time spent grazing during a 1-d period was determined in each of June, July and August of 1986 and 1987. Grazing time averaged 8.0 h d−1 and was not affected by season or fertility treatment. Forage and fecal contents of acid detergent lignin, ash and N were significantly correlated with the N fertility level of the pasture from which they came. It was concluded that forage intake of animals grazing N-fertilized pastures may be affected indirectly by the effect of soil N fertility on DMD. Key words: Psathyrostachys juncea, fecal output, feces composition, forage digestibility
The effect of organic acids and enzyme supplementation on the performance of pigs fed barley-based diets
Authors: Thacker P. A. , Campbell G. L. , Grootwassink J.
Published: March 2010

Two factorial design experiments (sex × treatment) were conducted to determine the efficacy of enzyme and organic acid supplementation on improving the nutritive value of barley-based diets for both starter and finisher pigs. For exp. 1, 48 crossbred growing pigs (25.1 ± 2.8 kg) were fed either a barley-based control diet or a similar diet supplemented with 0.25% enzyme (Aspergillus niger; 750 units g−1 beta-glucanase), 2.5% propionic acid or a combination of these additives during a 77-d feeding trial. For exp. 2, 120 crossbred weaner pigs (8.1 ± 1.3 kg) were fed a hulless barley-based control diet or a similar diet supplemented with 0.25% enzyme (Aspergillus niger; 750 units g−1 beta-glucanase), 2.0% fumaric acid or both additives in combination for a 35-d feeding period. In exp. 1, supplementation with either enzyme or propionic acid alone, significantly (P < 0.05) increased dry matter digestibility. However, when the additives were fed in combination, the digestibility coefficient for dry matter was not significantly different from the control. Digestibility coefficients for crude protein and energy were not affected by any treatment. Growth rate, feed intake, feed efficiency and carcass traits were also not improved by supplementation with enzyme or propionic acid, either when fed alone or in combination. In exp. 2, digestibility coefficients for dry matter, crude protein and energy were not affected by enzyme or acid treatment. In addition, there were no differences in growth, feed intake or feed efficiency as a result of any treatment. Supplementation with organic acids would therefore appear to be ineffective in potentiating the response to dietary beta-glucanase in pigs fed barley-based diets. Key words: Swine, barley, beta-glucanase, propionic acid, fumaric acid
Effect of index selection for reduced backfat thickness and increased growth rate on sow weight changes through two parities in swine
Authors: McKay R. M.
Published: March 2010

The impact of continued selection for reduced backfat thickness and improved growth rate on weight changes in Yorkshire and Hampshire sows, from breeding as gilts to weaning their second litter, was studied. Results suggest that some sow weight changes may have been influenced by selection pressure exerted. Key words: Sows, Canadian Yorkshire, Hampshire, liveweight change
Comparison of mammary-derived growth inhibitor production in mammary tissue of lactating-pregnant versus nonlactating-pregnant Holstein cows
Authors: Politis I. , Gorewit R. C. , Muller T. , Grosse R.
Published: March 2010

Production of mammary-derived growth inhibitor (MDGI) in mammary tissue of lactating-pregnant and nonlactating-pregnant (13–44 d after cessation of milking) Holstein cows was examined. High levels of MDGI were detected in mammary tissue obtained from cows which were concurrently lactating and pregnant. A reduction in MDGI production was observed in nonlactating-pregnant cows. Key words: Bovine, MDGI, lactation, dry period, pregnancy
Effect of insulin administration during follicular growth on serum glucose and hormone profiles in ewe lambs
Authors: Beam S. W. , Holcombe D. W.
Published: March 2010

Twenty ewe lambs received either 0 or 1 IU of Lente insulin kg−1 body weight from day 12 of the estrous cycle until 24 h after estrus. Blood samples were collected at 15-min intervals for 6 h after treatment on days 12, 14 and 16 of the estrous cycle. Following insulin injection, serum insulin was elevated (P < 0.05) and was accompanied by a decrease in serum glucose levels. Insulin treatment did not affect (P > 0.10) luteinizing hormone secretory characteristics, ovulation rate, or subsequent litter size. Key words: Insulin, glucose, sheep, luteinizing hormone
The influence of dietary monensin and salinomycin on growth and endocrine status of gilts
Authors: Lunen T. A. Van , Kirkwood R. N. , Thacker P. A.
Published: March 2010

Seventy-two gilts were fed a 16% crude protein diet supplemented with monensin, salinomycin or not supplemented. There was no effect of treatment on gilt growth between 30 and 100 kg body weight. Monensin-fed gilts tended to have increased, while salinomycin-fed gilts had decreased (P < 0.01), serum growth hormone concentrations. Salinomycin-fed gilts were older and heavier at puberty (P < 0.05). Key words: Monensin, salinomycin, gilts, growth, reproduction
Carrot/grass silage as cattle feed
Authors: Laflamme L. F.
Published: March 2010

Carrots and grass hay were ensiled together, stored in vertical silos, and compared to a bromegrass/alfalfa silage in a feeding trial using 20 weaned cattle. The carrot/grass silage ensiled well and was accepted by the steers. Growth performance was similar for both silages and the cattle responded to barley supplementation. Key words: Cattle, carrots, silage, feed
Prediction of lean content in the carcasses of beef cattle. I. From measurements of wholesale carcasses
Authors: Fan L. O. , Wilton J. W. , Usborne W. R. , McMillan I.
Published: March 2010

Carcass data on 304 steers and 320 heifers from seven breed of dam groups were analyzed to test equations designed to predict lean content as weight and proportion in beef carcasses from measurements of the wholesale carcasses. Measurements included cold-carcass weight (CW), average backfat (AB) thickness, longissimus muscle (LM), semimembranosus (SM), semitendinosus (ST) and biceps femoris (BF) muscle areas, hip weight, marbling and other quality scores as indirect measures of composition. Actual lean weights and proportions were obtained from physical separation of fat, lean and bone from one side of the carcass. Prediction equations were obtained from the overall data and subpopulations by breed of sire–degree of finish combination, by sex and by breed of dam group. For predicting lean weight in the carcass, CW, LM and AB were the most important predictors. Addition of hip weight, SM and ST improved both precision and accuracy. For predicting proportion lean in the carcass, the addition of hip percentage, SM and ST to CW, LM and AB improved precision. The overall equation including these six independent variables supplied precise estimates (r2 of 0.93–0.97) of lean weight with little bias (average biases of −0.54 to 0.41 kg) for all subpopulations. Important biases in predicting lean proportion were observed from some breed of dam groups, indicating that an equation derived from an overall population cannot be used without error for all subpopulations of breed of dam groups. Key words: Beef, carcass, prediction, lean content, breed, sex
Prediction of lean content in the carcasses of beef cattle. II. From measurements of specific cuts
Authors: Fan L. O. , Wilton J. W. , Usborne W. R. , McMillan I.
Published: March 2010

Carcass data on 304 steers and 320 heifers from seven breed of dam groups were analyzed to test equations for predicting weight and proportion of lean content in beef carcasses from measurements of specific cuts. All dams were bred to Angus sires for first calving and to a Simmental sire for second and third calvings. Cattle by Angus sires were slaughtered at 10-mm backfat thickness evaluated ultrasonically; those by the Simmental sires at 7 mm. One side of each carcass was cut into eight cuts and separated into fat, lean and bone. Data were analyzed by multiple stepwise regression procedures. Prediction equations from each cut were obtained from the overall data and subpopulations by breed of sire, by sex and by breed of dam group. Cold-carcass weight accounted for the highest proportion of variation of lean weight in the side of the carcass, but it accounted for no more than 3% of the variation of proportion lean. Lean weight in hip and chuck, particularly in hip, was a most important predictor for estimating lean weight of the side. Total weights of each cut were also important predictors. Proportion lean in each cut alone was the strongest predictor of proportion lean in the carcass. Proportions of weights of cut in the carcass were also important predictors. Predictions of lean content (weight and proportion) in the carcass from dissected cuts of chuck and hip provided the most precise estimates. Average biases for breed of sire–degree of finish combinations, sex or breed of dam group were relatively small when an overall equation based on information from the hip was used. Key words: Beef, prediction of lean content, carcass, cuts, breed, sex
Effects of exogenous porcine somatotropin on performance, testicular steroid production and fat levels of boar-taint-related compounds in young boars
Authors: Bonneau M. , Meadus W. J. , Squires E. J.
Published: March 2010

Large White × Pietrain boars were administered 0 or 5 mg recombinant porcine somatotropin (pST) daily between 68 and 105 kg live weight in an investigation of the effects of pST treatment on growth performance, carcass traits, genital-tract development, steroid-hormone synthesis, and fat skatole and androstenone levels in young male pigs. Growth rate was not affected by pST treatment, daily feed intake was decreased 9% (P < 0.05), and feed efficiency was improved 7% (P < 0.01). Muscle content of the carcass was increased from 57.7% to 59.7%, and fat content was reduced from 18.8% to 15.7% (P < 0.001). Genital-tract development, testicular androgen and 16-androstene biosynthesis rates and skatole levels in fat were not affected by pST treatment. Androstenone levels in fat were reduced from 0.66 μg g−1 in control animals to 0.35 μg g−1 in pST-treated animals (P < 0.001). The results of the present experiment indicate that pST treatment of boars of a lean genotype significantly improves the performance of the animals and may contribute to a reduction in the incidence of boar taint. Key words: Boar taint, somatotropin, skatole, androstenone, pigs
Influence of the β-adrenergic agonist cimaterol on energetic efficiency and oxygen consumption in liver tissue of growing lambs
Authors: Caine W. R. , Mathison G. W.
Published: March 2010

The effects of dietary cimaterol on energetic efficiency and liver oxygen consumption were evaluated using 14 wether lambs. Lambs were fed at a low intake (491 kJ kg−0.75 d−1 metabolizable energy (ME)) followed by a high intake (919 kJ ME kg−0,75 d−1). Five control animals received a pelleted alfalfa diet and five received a diet in which cimaterol was added at a level of 10.9 mg kg−1 dry matter. Four additional animals received no cimaterol at the low intake level and 10.9 mg kg−1 dry matter at the high intake. Indirect calorimetry measurements were conducted over a 24-h period on day 22 at each feeding level. Digestibility of dry matter and energy were not affected by cimaterol treatment. Methane production as a percentage of gross and digestible energy intake was increased (P = 0.04) 19% by cimaterol treatment at the 1.1 × M feeding level. Heat production was not affected by cimaterol treatment. Maintenance requirements (kJ ME kg−0.75 d−1) ranged from 314 to 438 for control and from 402 to 458 for cimaterol-treated lambs, depending upon the method of estimation. Energy costs of protein accretion (kJ ME kJ−1 deposited) in control lambs, estimated by a complete multiple regression procedure, by a multiple regression procedure following estimation of maintenance requirements by a semilog-linear procedure, and by assuming a constant efficiency for fat synthesis, were 4.85, 2.54 and 2.91, respectively. Corresponding values for cimaterol I lambs were 2.64, 1.65 and 1.98. Using estimates of protein synthesis obtained from radiolabelled leucine kinetics, the cost of protein synthesis was estimated as 1.25 kJ ME kJ−1 protein synthesized. Estimated energy costs of fat accretion were 0.56–1.13 and 0.94–1.30 kJ ME kJ−1 for control and cimaterol I lambs, respectively. Na+, K+-ATPase-dependent oxygen consumption rate of liver tissue tended (P = 0.06) to be reduced by 20% for cimaterol I compared with control lambs. Key words: Lambs, cimaterol, energy efficiency, protein, fat, Na+, K+-ATPase
Effect of dietary potassium on concentration of lysine in plasma of finishing cattle
Authors: Newton G. L. , Hill G. M. , Beaver R. W. , Mullinix Jr. B. G.
Published: March 2010

High K intakes have been shown to affect lysine metabolism in swine and poultry. This effect may result in improved performance and its primary manifestation is a decrease in plasma and tissue lysine concentration. In order to evaluate the effects of supplemental K and crude protein (CP) on the concentration of amino acids in plasma (PLAA) and growth performance, 72 cattle (48 heifers + 24 steers, weighing 425 ± 35 kg) were allotted to a 2 × 2 factorial arrangement of dietary treatments in a randomized complete block design trial. After 28 d on feed, there was a trend (P = 0.09) for an interaction effect of K (1% KCl) and CP (6% cottonseed meal) on plasma lysine. At 56 d there was an interaction (P = 0.02) of K and CP on plasma lysine. Supplemental K decreased (P = 0.01) plasma lysine in the absence of CP supplement, and increased it (P = 0.04) in the presence of CP. Supplemental CP decreased (P = 0.001) plasma lysine in the absence of supplemental K, but not in its presence. Addition of K, CP or both K and CP to the corn-peanut hull diet did not affect weight gain or feed efficiency. Addition of CP tended (P = 0.09) to increase feed intake over the entire trial. Carcass quality grade was lower (P = 0.03) for cattle fed CP supplement than for cattle not fed supplemental CP. Key words: Cattle, potassium, crude protein, plasma amino acids, lysine
Catch-up growth of yearling wapiti stags (Cervus elaphus)
Authors: Wairimu S. , Hudson R. J. , Price M. A.
Published: March 2010

Ten yearling wapiti stags were used to investigate effects of winter nutrition on subsequent growth on summer pasture. One group of five (LOW) was wintered on medium-quality hay, and the other group of five (HIGH) was wintered on hay and alfalfa–barley pellets (16% crude protein). By the time they grazed spring pasture in mid-April, HIGH wapiti had larger frame dimensions and were 20 kg heavier than those wintered on hay alone, despite their lower pre-winter weights. However, subsequent catch-up growth rapidly narrowed these differences, and both groups attained similar weights and frame measurements by late July. Liveweight gains on summer pasture were 0.30 and 0.15 kg d−1 for LOW and HIGH wapiti, respectively. Although LOW wapiti tended to have higher gut fill (3.3 vs. 2.5 kg dry matter), the difference (corrected for assumed dry-matter content) was insufficient to explain compensatory weight gain. Digestibilities and mean retention times did not differ consistently between the treatment groups but were reciprocally related to one another. Forage intakes rose as pastures flushed but declined sharply in July with overgrazing and resumption of supplemental feeding. LOW wapiti consumed more pasture dry matter than HIGH wapiti in May and June. Efficiencies of forage utilization were unrelated to nutritional history. Using data pooled for the two treatment groups from April to June gave estimates of 878 kJ W−0.75 for maintenance and 33.4 kJ g−1 for liveweight gain. The main factor contributing to compensatory gain on summer pasture was higher forage intakes, particularly in relation to metabolic weight. Key words: Game farming, elk, compensatory growth, forage intake, passage rate, energy requirements
Effects of dietary fat supplementation and recombinant bovine somatotropin on milk production, nutritional status and lipid metabolism of dairy cows
Authors: Marty Bruno J. , Block Elliot
Published: March 2010

Sixty dairy cows were used to evaluate the effect on performance, metabolism and liver function of adding dietary fat during early lactation (weeks 3–15 postpartum) and injecting recombinant bovine somatotropin (rbST) over the entire lactation. Fat was added to an 18% protein concentrate that was offered in a 1:1 ratio of haylage:concentrate and fed as a total mixed ration. Corn in the control (CRT) concentrate was exchanged for either 2.5% animal fat (AFA), 2.5% Megalac™ calcium salts of fatty acids (CSFA) (ML1), 2.5% Purina CSFA (RP1) or 5% Purina CSFA (RP2). RbST treatment consisted of a subcutaneous injection of either a placebo, 10.3 mg rbST daily or 350 mg rbST every 14 d. Fat-corrected milk production was higher (P < 0.05) in RP2-fed cows than CTR-fed cows and higher for cows injected with rbST daily than in those injected biweekly. Plasma-urea nitrogen and insulin concentrations were lower in RP2-fed cows than in CTR-fed cows and were also lower in rbST-injected cows than in placebo-injected cows (P < 0.05). Plasma triglyceride (TG) and cholesterol concentrations, but not non-esterified fatty acid and phospholipid concentrations, were higher (P < 0.05) in RP2-fed cows than in CTR-fed cows. CSFA supplementation increased C16:0 of the plasma TG fraction and decreased that of C18:0. Dietary fat supplementation did not affect hepatic lipid composition, but liver-TG concentration increased (P < 0.05) with rbST injections. Dietary fat supplementation together with somatotropin injections did not change production parameters from those found with fat supplementation or somatotropin alone. Key words: Dietary fat, dairy cows, bovine somatotropin, lipids
Effect of supplementary energy and protein feeding on the true digestion of grass-silage organic matter, cell walls and nitrogen estimated by the combined synthetic-fibre-bag method in cows
Authors: Varvikko Tuomo , Vanhatalo Aila
Published: March 2010

Four ruminally and duodenally cannulated non-lactating Finnish Ayrshire cows were used in a balanced 4 × 4 Latin square to study the effect of different concentrate supplements on the true partial and total-tract digestion (TTD) of grass silage, estimated by using the combined rumen-bag-intestinal-bag method. The cows were fed, at maintenance level, grass silage alone or supplemented with good-quality ground barley, ground barley and rapeseed meal, or ground barley and soybean meal. The determination of the proportion of grass silage degraded in the rumen (RD) was based on disappearance of feeds from nylon bags during the rumen incubation as a function of time, using the outflow rate of k = 0.0625. The intestinal digestion (ID) was estimated by the mobile-bag method with the residues that resisted degradation during the 16-h rumen incubation. Combination of these two was calculated to provide the TTD. Concentrate supplementation always caused a clear and consistent decline in rumen degradation and TTD of organic matter (OM), neutral detergent fibre (NDF) and Kjeldahl-N of grass silage but had no real influence on its ID. The type of concentrate, however, had only little effect. The average TTD of NDF was 16% lower than that of OM, but TTD of N was always very much higher than the respective value for OM. The results indicate that concentrate supplementation decreases the total-tract digestion of OM, cell walls and nitrogen of grass silage owing to impaired ruminal degradation. The combined bag method appears a convenient tool to provide digestion coefficients close to the true feed digestion of the individual feeds. Key words: Grass silage, nylon bag, mobile bag, combined bag, ruminal degradation, intestinal digestion, true digestion
Effect of feeding supplemental fat or lysine during the postweaning period on the reproductive performance of sows with low or high lactation body weight and fat losses
Authors: Grandhi R. R.
Published: March 2010

The effects of feeding supplemental fat or lysine during the postweaning period on breeding and subsequent reproductive performance were determined in two experiments of a 2 × 3 factorial design, using 168 Landrace × Yorkshire first-parity (exp. 1) and 180 Yorkshire second-parity (exp. 2) sows. At the end of lactation, they were divided into two groups: LWL (< 14 kg) and HWL (> 14 kg) based on 3 wk lactation weight loss. The three experimental diets fed during the postweaning period were: (1) control; a 12% gestation diet fed 2 kg d−1 (24.7 MJ DE, 9.4 g lysine d−1); (2) Fat; control diet plus animal fat to provide approximately 50% more daily energy intake (37.0 MJ DE d−1); and (3) Lysine; control diet plus lysine to provide approximately 50% more daily lysine intake (14.4 g d−1). After breeding, all sows were fed the control diet at 2 kg d−1, and they were killed at 30 d of gestation to evaluate their reproductive performance. High weight loss during the lactation period increased the incidence of anestrus and reduced the pregnancy rate in first-parity sows. Feeding supplemental fat was beneficial in increasing the proportion of sows in estrus within 7 d postweaning and the pregnancy rates of first-parity sows with high lactation weight loss. Supplemental fat also had a beneficial effect on ovulation rate, the number of normal embryos, fetal survival and the fetal weights, whereas supplemental lysine improved only fetal weights. Feeding supplemental fat or lysine improved only ovulation rate in second-parity sows with high lactation weight loss. The results indicated that feeding supplemental fat or lysine can improve the postweaning reproductive performance of sows that had high weight and fat losses during lactation. Key words: Sows, estrus, ovulation, embryo survival, fat, lysine
Estimation of an acceptable β-glucan level for broiler chick diets
Authors: Cave N. A. , Wood P. J. , Burrows V. D.
Published: March 2010

An experiment was conducted to estimate the maximum amount of β-glucan that can be included in a broiler chick starter diet without impairing performance. Oat bran and fat were substituted for corn in a corn–soy diet to provide iso-energetic β-glucan levels of 6.3, 9 and 31 g kg−1 diet. Performance criteria were analyzed for regression on β-glucan level. Impairment of performance was greater for weight gain (W, g day−1) than for excreta condition or feed efficiency. An acceptable dietary β-glucan (G) level (g kg−1) was identified with the predicted performance equal to that of the control diet, from the response surface, W = 28.2 + 0.117 G − 0.00951 G2. Growth impairment was predicted to appear in young broiler chicks only as β-glucan level is increased in iso-energetic diets above 12.3 ± 0.46 g kg−1; conversely 1 and 2% growth inhibitions were predicted when dietary β-glucan levels equal 14.4 and 16.0 g kg−1, respectively. Key words: β-glucan, oats, chick, growth inhibition
Efficiency of nonsurgical collection of embryos from superovulated cows on day 5
Authors: Hackett A. J. , Durnford R. , Marcus G. J.
Published: March 2010

Nonsurgical collection of embryos from superovulated cows on day 5 (day 0 = day of onset of estrus) yielded fewer embryos than expected in comparison with the yield of oocytes collected surgically on day 1 and of embryos collected surgically on day 3. The yields were 16.5 oocytes, 16.8 embryos and 2.9 embryos and/or oocytes on days 1, 3 and 5, respectively. The low yield on day 5 was not explained by retention of embryos, as only 3 of 58 cows flushed were later found to be still pregnant. Key words: Superovulation, embryos, embryo recovery, bovine
Reasons for disposal of cows in a purebred Hereford and two multibreed synthetic groups under range conditions
Authors: Arthur P. F. , Makarechian M. , Berg R. T. , Weingardt R.
Published: March 2010

Reasons for disposal were determined for 983 cows from a purepred Hereford and two multibreed synthetic groups; all were born in the 1966–1975 period. One synthetic group (Beef Synthetic #1) was composed mainly of beef breeds, while the other synthetic group (Dairy Synthetic) had 64% dairy breeding. The cows were managed under a stringent culling policy under which any cow failing to wean a calf each year was culled. Cows were also culled for unsoundness and other defects. The mean longevity was 4.2 yr, with 16 yr being the maximum age attained by any cow. The highest percentage of cows was disposed as 2-yr olds (first calvers). Death losses accounted for 8.8%, while culling for reproductive failure, calf survival problems, calving problems and udder problems accounted for 51.3, 12.1, 10.9 and 7.7% of all disposals, respectively. Culling for reproductive failure was the major reason for disposal at all ages, although its relative importance diminished with advancing age. Culling for udder problems was of greatest significance in 6-yr-old and older cows. Culling for calf survival problems was higher (P < 0.05) in the Hereford than in the two synthetic groups. While mortality in the Dairy Synthetic group was higher (P < 0.05) than in the other two groups, the reverse was the case with respect to culling for severe calving problems, with Dairy Synthetic cows being culled the least (P < 0.05). Key words: Beef cattle, longevity, mortality, culling, breed
Genetic differences among the predominant beef cattle breeds in Canada: An analysis of published results
Authors: Amer P. R. , Kemp R. A. , Smith C.
Published: March 2010

Published information on the relative performance of beef breed crosses was used to derive single estimates of purebred breed values for the predominant beef breeds in Canada. A range of commercial traits was considered. The breed cross estimates were taken from four large breed comparison trials from 1970 to 1983, each with representative samples of the breeds from the North American population. Variances of the breed cross estimates, derived allowing for the number of sires and progeny sampled, were used in a Weighted Least Squares analysis to obtain single purebred breed effects. Birth weight, and growth rate breed values were also expressed on a 1991 base by adjusting for the estimated breed genetic trends. Important genetic differences are shown to exist between the breeds for many of the traits. Breeds with larger mature size tended to be larger and leaner at a constant age and better for maternal calving ease and maternal calf survival. In contrast, smaller breeds were superior in their direct genetic contribution for calving ease and calf survival. Angus were more fertile and Simmental less fertile than the other breeds. Knowledge of these differences has a wide range of applications, including the provision of a biological basis for the economic comparison of breed crossing systems and for the definition of breed roles in beef production. Key words: Beef breeds, genetic differences, genotype-environment interaction
Differences in production and type trait selection differentials between bulls used in official and owner/sampler dairy herds
Authors: Brown T. P. , Cue R. I.
Published: March 2010

Differences in the emphasis placed on type and production traits between bulls used in official herds and those used in owner/sampler (O/S) herds registered at the Quebec Dairy Herd Analysis Service were calculated. For 543 881 Holsteins and 41 955 Ayrshires, service records (containing the cow and service sire identification and the service sire's production and type proofs) were used to calculate selection differentials (SD) for the bulls used in official and O/S herds for each 6-mo period between 1980 and 1983. An SD was calculated as the difference between a bull's proofs in a service record and the average proof of all bulls available in the same period. Selection differential means and variances were calculated within each herd, and the average and variance of these means were determined for each 6-mo period. Differences in SD between bulls used in official and O/S herds were determined using the Student's t-test for differences between means. Within Holsteins, SD for final class, general appearance, fore udder, rear udder, size and stature of bulls used in official herds were significantly higher in O/S herds. Within Ayrshires, no significant differences in type-trait SD were found because a very small number of prominent bulls were used extensively throughout both official and O/S Ayrshire herds. Although not significant, in all periods production trait SD tended to be higher for bulls used in O/S herds than for bulls used in official herds for both Holsteins and Ayrshires. Key words: Dairy cattle, bull selection, official, owner/sampler
Effect of prolonged thermal exposure on heat production, reticular motility, rumen-fluid and -particulate passage-rate constants, and apparent digestibility in steers
Authors: Miaron J. O. Ole , Christopherson R. J.
Published: March 2010

Six steers fitted with permanent rumen cannulae and fed alfalfa-grass hay were kept at either −10, 10 or 28 °C for 21 d to evaluate the effects of prolonged thermal exposure on heat production (HP) and digestive responses. HP was lowest at 28 °C and increased significantly (P < 0.05) as the temperature was reduced to −10 °C. The duration of the biphasic reticular contraction during resting was significantly (P < 0.05) reduced at −10 °C (5.4 s) compared with that at 10 °C (5.7 s) and 28 °C (5.7 s) whereas duration and amplitude of biphasic reticular contractions during rumination were elevated at −10 °C (P < 0.05). Apparent digestibilities of dry matter, organic matter, neutral detergent fibre and crude protein on average were 11% (range 9–16%) higher (P < 0.05) at 28 than at 10 °C. The particulate passage-rate constant was higher at −10 °C (P < 0.05) than at 10 and 28 °C (0.046 vs. 0.038 and 0.034, respectively). The fluid passage-rate constant showed a quadratic response to temperature and was inversely related to digestibility. This study suggests that thermal exposure not only affects rumen particulate and fluid kinetics but also influences the form and pattern of reticular contractions. Further, the temperature-induced changes in duration and amplitude of reticular contractions during rumination were associated with changes in particulate passage-rate constants. Key words: Environmental temperature, reticulum, motility, fluid and particulate passage rates, digestibility, steer