bluuebunny/crossref_metadata_2025 huggingface dataset:
Winter performance of Hereford cows on fescue prairie and in drylot as influenced by fall grazing
Authors: Willms W. D. , Rode L. M. , Freeze B. S.
Published: March 2010

An experiment was conducted to determine the feasibility of winter grazing pregnant Hereford cows on fescue prairie. The experiment was replicated over a 4-yr period (1988–1991, n = 4) and utilized a 2 × 2 factorial design representing fall grazing (September to November) on annual pasture (winter wheat and corn) or fescue prairie; and winter grazing (November to the end of February) on fescue prairie or feeding in a drylot. The cows weighed an average of 519 kg and had an average of 4.4 mm of backfat in late May when summer grazing on fescue prairie began and 7.2 mm of backfat at the beginning of fall grazing. Measurements of cow backfat and cow weights at each feeding change indicated that during the fall grazing period, average daily gain (ADG) was −0.43 kg and change of backfat was −1.0 mm on fescue prairie compared with + 0.12 kg and + 0.9 mm, respectively, on annual forage. Fall grazing of annual forages had no effect on the ADG of cows in winter but resulted in higher backfat after the winter feeding period (5.3 vs. 4.1 mm, P = 0.009). In later winter, cows kept on fescue prairie over the entire grazing period averaged 3.5 mm of backfat, while the cows grazed on annual forages in the fall and wintered in the drylot averaged 5.7 mm. Cows may be kept on fescue prairie in fall and winter. However, feed supplementation is needed to achieve optimal condition at calving. Fall grazing of annual forages may allow cows to maintain their body weight on fescue prairie, minimizing costly feed inputs prior to calving. Key words: Cows, calves, annual forage, backfat, fall grazing
A comparison of tall fescue and orchardgrass silages for lactating cows
Authors: Fisher L. J. , Bittman S. , Hunt D. E. , Shelford J.A. , Mason B. D.
Published: March 2010

The feeding value of tall fescue silage (Festuca arundinacea schreb.) harvested at the boot stage of maturity with a crude protein (CP) content of 15.4% was compared to that of orchardgrass silage (Dactylis glomerata) harvested at the same stage of maturity with a CP content of 12.5%. Two feeding trials with lactating cows were used in this comparison. The first trial employed 10 cows in a 2 × 2 Latin- square, with treatment period 35 d in length. In the second experiment five cows were used in a preference trial where individual feed intakes, duration of feeding, and rate of forage consumption were monitored electronically for a period of 9 d.In the first trial, the cows consumed more tall fescue than orchardgrass silage (P < 0.05) (14.08 vs. 12.90 kg d−1 dry matter (DM)) but there were no differences between cows fed the two silages in milk yield (30.4 vs. 29.8 kg d−1) or milk compositon. Source of silage did not influence rumen fluid pH, molar percent of volatile fatty acids or plasma glucose; however, plasma urea-N levels were significantly higher (P < 0.05) (17.00 vs. 15.14 mg dL−1) when cows were fed tall fescue silage compared with when they were fed orchardgrass silage. In the preference trial employing electronically monitored forage feeding gates, all five cows demonstrated a preference for the tall fescue silage consuming a daily average of 9.83 kg DM for tall fescue compared with 3.73 kg for orchardgrass silage. Cows spent more time (P < 0.05) (68.3 vs. 14.1 min−1) and ate faster (69.6 vs. 54.0 g DM min−1) from the gates offering tall fescue silage compared with the gates offering orchardgrass silage. From the results of these two trials it was concluded that tall fescue silage was comparable to orchardgrass in supporting milk production and superior to orchardgrass in terms of palatability. Key words: Tall fescue, silage preference, lactating cows
Feed efficiency in once-calved and conventional systems of heifer beef production
Authors: Newman J. A. , Jones S. D. M. , Price M. A. , Vincent B. C.
Published: March 2010

A total of 120 crossbred heifers (initial weight = 270 ± 3 kg) were used in a project to evaluate a once-calved-heifer system of beef production. They were reared on a cereal silage–grain diet and, beginning at an average age of 385 d, exposed during a 6-wk breeding period to bulls of breeds chosen for calving ease. Ninety-six heifers reared calves to weaning. The calves were weaned and the heifers were slaughtered 3, 5 or 7 mo after calving, and the feed conversion efficiency of these treatment groups was compared with that of a similar group of 32 heifers slaughtered at 457 d of age after a conventional feeding program. Feed conversion calculations included the combined cow–calf unit for heifers that had reared a calf and were based on weaning-day and end-of-test (27 Sept.) endpoints. During the post-calving period, the late-weaned cow–calf units tended to be more efficient to the point of weaning, but the early-weaned ones were significantly more efficient if the calf's performance from weaning to the end of test was considered. From the start of test to the weaning endpoint, conventionally reared heifers were significantly more efficient than early-weaned once-calved heifers on many of the bases studied. To the end-of-test endpoint, however, they did not differ significantly (e.g., 411.4 ± 20.5, vs. 402.1 ± 29.0, 441.0 ± 29.0 and 460.2 ± 29.0 MJ DE kg−1 lean product weight for conventionally reared vs. 3-, 5- and 7-mo-weaned once-calved heifers). These results suggest that animals in a once-calved-heifer system of beef production can utilize digestible energy as efficiently as those in a conventional system if conception failure and calf losses can be controlled. Key words: Beef production, heifers once-calved, feed efficiency
The effect of selenium supplementation on plasma sulphur, magnesium and selenium profiles of dairy cows
Authors: Batra T. R. , Hidiroglou M.
Published: March 2010

Interaction of Se supplementation with sulphur and magnesium in blood plasma were studied in dairy cows. Cows were divided into three groups: (1) control, no treatment; (2) cows injected intramuscularly 21–10 d prior to parturition with 45 mg Se and 2040 IU of vitamin E; (3) cows intraruminally administered with two 30-g pellets containing 10% elemental Se 2 mo prior to expected calving. There were no significant effects of Se supplementation on the plasma levels of sulphur and magnesium. Key words: Selenium, sulphur, magnesium, blood, cattle
Phospholipase A2 activity in fresh and cryopreserved spermatozoa from boars
Authors: Dyck M. K. , Buhr M. M.
Published: March 2010

The enzyme phospholipase A2 (PLA2) is considered to play an important role in the fertilizing ability of mammalian spermatozoa, but PLA2 activity has not been identified in boar spermatozoa. Fertility rates obtained using cryopreserved boar semen are considerably less than those with fresh boar semen, which might be attributed to altered PLA2 activity. Phospholipase A2 activity, determined by the formation of radiolabelled fatty acid from a radiolabeled phospholipid substrate, was successfully detected in the sonicates and acid extracts of boar spermatozoa. The PLA2 in acid extracts was calcium-dependent, active at neutral and alkaline pH and was maximized with increasing incubation temperatures, time and spermatozoal protein. Assaying acid extracts under conditions of 35 °C, 24 h, pH of 7.5 and 2 mM calcium, the PLA2 activity of freshly collected boar spermatozoa was found to be 8.22 ± 1.47 pmoles palmitic acid h−1 mg−1 protein (mean ± SE). Matched samples of spermatozoa exposed to cryopreservation had a significantly lower (P < 0.05) activity of 4.26 ± 0.59 pmoles palmitic acid h−1 mg−1 protein. This study has identified PLA2 in boar spermatozoa for the first time and determined that its activity is reduced by procedures known to reduce fertility. Key words: Phospholipase, boar, semen, cryopreservation
Naked oats in grower and finisher diets for male chicken roasters and female turkey broilers
Authors: MacLean J. , Webster A. B. , Anderson D. M.
Published: March 2010

Two experiments were conducted to evaluate naked oats as a feedstuff for male chicken roaster and female turkey broilers. In exp. 1, grower and finisher roaster diets were formulated to contain 18, 36, 54, or 72% naked oats (Avena nuda L. 'Tibor'). The starter diet contained no naked oats. Two trials were conducted utilizing 1344 birds. Treatment diets were fed to four pens of roasters each, from 21 to 64 d of age. In exp. 2, grower and finisher turkey diets were formulated to contain 0, 22, 44, or 66% naked oats. The starter diet contained no naked oats. Two trials involving 964 birds were conducted. Treatment diets were fed to four pens of turkeys each, beginning at 21 d of age. Level of naked oats did not affect weight gain, feed efficiency or mortality of the roasters. The turkey poults consuming the 66% naked oats diet had significantly heavier 10-wk body weights and greater weight gains from 3 to 10 wk of age than those fed the other diets. In Trial 1, treatment had no significant effect on weight gains or feed efficiency for the finishing period (10–16 wk). In Trial 2, birds fed the 66% naked oats diet consumed significantly less feed than those fed the other diets, and had significantly heavier 12-wk body weights than birds fed the 22 and 44% naked oats diets. Treatment had no significant effect on weight gain or feed efficiency for the finishing period (10–12 wk). It appears that naked oats were a suitable feedstuff for the birds in this study. Key words: Naked oats, chicken roaster, turkey broiler, growth
Sources of variation in age at smolting in hatchery-reared Atlantic salmon (Salmo salar)
Authors: Bailey J. K. , Friars G. W.
Published: March 2010

Length-frequency distributions of Atlantic salmon parr are bimodal during the first November post-hatch and the proportion of presumptive 1 + smolts (S1) can be estimated by integrating the area under the upper modal curve. Such proportions were found for a total of 179 full-sib families of approximately 1000 fish per family. Variance between families suggested genetic effects although an unbiased estimate of heritability was not obtainable because of the experimental design. Correlations between length measurements in July and November were significantly (P < 0.01) greater than zero and families, with a mean length advantage in the lower size mode, also tended to produce larger fish in the upper mode. There was a negative correlation (P < 0.07) between mean length in July and the proportion of presumptive 1 + smolts. Thus, while selection for increased size during July would be expected to produce a positive, correlated growth response in both modes in November, a decrease in the number of 1 + smolts would be expected. Key words: Salmon, smolting age, Salmo salar, hatchery
Differentiation of the effects of somatotropin and enhanced growth rate on the occurrence of osteochondrosis in pigs
Authors: He P. , Aherne F. X. , Nakano T. , Schaefer A. L. , Jones S. D. M. , Thompson J. R.
Published: March 2010

One hundred and twenty Yorkshire pigs, equal numbers of gilts and barrows, with an initial average weight of 69 kg were used in the present experiment. The animals were treated with 2 mg d−1 of recombinant porcine somatotropin (rpST) either by daily injection or by slow-release implant, while the control animals were treated with a sham implant. The daily injection of rpST increased daily weight gain (P < 0.0001) and decreased feed/gain ratio (P < 0.0001) and daily feed intake (P < 0.0001). Barrows grew faster (P = 0.02) and ate more feed (P = 0.0001) than gilts. On reaching ~ 100 kg, all pigs were slaughtered, and 60 pigs (two from each pen) were randomly selected for carcass evaluation. Carcass lean content was increased (P < 0.0001) and carcass fat content was decreased (P < 0.0001) in animals treated with rpST by daily injection. Animals treated with rpST by the slow-release implant were not different from the control animals in terms of growth performance and carcass characteristics. No overt lameness was observed in any of the pigs in the experiment. However, rpST treatment, regardless of the method of administration, increased the incidence and severity of osteochondrosis and reduced glycosaminoglycan concentration in the cartilage of the weight-bearing area of humeral and femoral condyles. These changes were independent of enhanced growth rate and carcass lean content. The results indicated that somatotropin treatment predisposes pigs to osteochondrosis. Key words: Osteochondrosis, growth rate, growth hormone, joint cartilage, pigs
Changes in ovarian follicular dynamics and luteinizing hormone profiles following different progestagen treatments in cattle
Authors: Taylor C. , Manikkam M. , Rajamahendran R.
Published: March 2010

Twelve cyclic non-lactating cows were allocated at random to three treatment groups (IN, NP and 2N). Cows in the 1N group (n = 4) received an ear implant containing Norgestomet at pro-estrus (day 0 = day of Norgestomet-implant insertion). Cows in the NP group (n = 4) received a progesterone-releasing intravaginal device 3 d after a Norgestomet implant at pro-estrus, and cows in the 2N group (n = 4) received a second Norgestomet implant 3 d after the first implant at pro-estrus. Treatments were terminated on day 9. Ultrasonic examination of the ovaries was carried out before, during and after treatment to monitor follicular dynamics. Serial blood samples were collected every 15 min for 8 h from all cows on days 3 and 6 after initiation of treatments to characterize the luteinizing hormone (LH) profiles. The dominant follicle was maintained for 9 d in all IN cows, and upon implant removal all cows ovulated. In both NP and 2N cows, the dominant follicle regressed and a new cohort of small follicles appeared before the end of the treatment. The dominant follicle from this pool ovulated after implant removal in all NP cows. In the 2N group, only one cow ovulated after implant removal; the dominant follicles in the remainder became cystic and did not ovulate. Decreases in pulse frequency, amplitude and mean plasma LH were observed in the NP cows, compared with IN cows (P < 0.05), but no change in LH-pulse frequency was observed in the 2N cows. This study shows clearly that maintenance and regression of the dominant follicle are associated with changes in progesterone and LH environment. Key words: Progestin, dominant follicle, ultrasound, regression, luteinizing hormone, cattle
Effect of flame roasting of dietary grains on the performance of leghorn hens
Authors: Hamilton R. M.G.
Published: March 2010

Two experiments examined the effect on the performance of Leghorn hens given diets containing flame-roasted grains from 140 to 490 d of age. In exp. 1, the inclusion of barley, corn and wheat roasted at 121, 119 and 149 °C, respectively, had no significant (P > 0.05) effect on productive performance. Experiment 2 contained a factorial arrangement of treatments that involved two sources of dietary barley (non-roasted or flame-roasted at 154 °C), two methods of milling (hammer or roller) and two dietary protein levels (15 or 18%). Hens given the diets that contained roasted barley had lower (P < 0.01–0.001) 490-d body weights, egg production, early egg weight (196 d) and number of extra large sized eggs, and higher (P < 0.05–0.01) feed conversion, monetary returns, interior egg quality and number of medium sized and grades B and C eggs than those fed the non-roasted barley control diet. Mortality, the number of large-sized eggs and egg weights, feed conversion and the occurrence of blood spots were higher (P < 0.05–0.001) while the number of medium-sized eggs was lower (P < 0.05–0.001) when the hens were fed roller compared with hammer-milled grains. Hens given the 18% protein-containing diets had higher (P < 0.05–0.01) 490 d body weight, egg production, monetary returns and numbers of small sized and grades B and C eggs, but lower (P < 0.05) mortality than those receiving the diets that contained 15% protein. Key words: Flame roasting, dietary grains, Leghorn hens
Environmental and genetic effects on birth weight in graded-up goat kids
Authors: Sánchez G. F. F. , Montaldo V. H. , Juárez L. A.
Published: March 2010

A linear model analysis was carried out to study the effect of sex, litter size, age of dam, year, birth period and genetic group on birth weight in goats. Genetic groups consisted of graded-up goats from backcrosses of local goats with Alpine, Granadina, Nubian, Saanen and Toggenburg sires, classified as low grade (from 1/2 to 3/4 of exotic genes) and high grade (over 3/4 of exotic genes). Heritabilities were also obtained for low- and high-grade kids. The data concern 4623 records from a farm under a stall feeding system in the north of Mexico. All of the main fixed effects but only the genetic group × birth period interaction were significant (P < 0.05). Males were heavier than females and singles were heavier than double and multiple-born kids. Birth weight means increased as dam age increased. Birth weight means for high and low grade kids were, respectively, 3.3 and 3.2 kg in Alpine kids, 3.1 and 3.2 in Nubian, 2.7 and 2.9 in Granadina, 3.3 and 3.3 in Saanen and 3.3 and 3.1 in Toggenburg. Heritability estimates were 0.40 ± 0.14 and 0.44 ± 0.18 in high and low grade kids, respectively. Key words: Goat kids, birth weight, Alpine, Granadina, Nubian, Saanen, Toggenburg, crossbreds, heritability, non-genetic factors
Additive and non-additive genetic effects of growth-curve parameters of Holstein, Ayrshire and crossbred females
Authors: Perotto D. , Cue R. I. , Lee A. J. , McAllister A. J. , Batra J. R. , Lin C. Y. , Roy G. L. , Wauthy J. M.
Published: March 2010

Crossbreeding parameters (line additive, dominance and additive × additive epistatic effects for individual and for maternal performance) on growth traits of females from a crossbreeding experiment between Holstein-based (HS) and Ayrshire-based (AS) lines were estimated by individual animal models, incorporating all known additive genetic relationships among animals, through restricted maximum likelihood and mixed-model methodologies. The growth traits [asymptotic weight (A), rate parameter (k), inflection parameter (m), average lifetime absolute growth rate (AGR), average lifetime absolute maturing rate (AMR) and average lifetime relative growth rate (RGR)] were estimated by fitting the Richards function to the observed growth curve of 3076 individuals. The statistical model included the random effect of the animal breeding value and the fixed effects of genetic group and station–year–season of birth. Results indicated that the HS exceeded (P < 0.001) the AS in additive effects for individual performance for both A and AGR. The HS exceeded (P < 0.05) the AS in additive effects for maternal performance for A. Individual heterosis was positive for A (P < 0.001) and for AGR (P < 0.01). Maternal heterosis was negative for A (P < 0.05) and positive for AMR (P < 0.05). Total heterosis (TH) had positive effects on both AGR and AMR (P < 0.05). Heterosis retained in advanced crossbred generations was not significant (P > 0.05) for any of the studied traits. The results suggest that crossbreeding designed to exploit TH can alter the shape of the growth curve of dairy cattle. Key words: Crossbreeding, dairy cattle, growth curve
Evaluation of solvent and expeller linseed meals as protein sources for dairy cattle
Authors: Khorasani G. R. , Kennelly J. J. , Robinson P. H.
Published: March 2010

The objectives of the present study were to evaluate the nutritive value of expeller linseed meal (ELM) and solvent linseed meal (SLM) as protein supplements for lactating dairy cows utilizing analytical and in situ procedures, and determine the in vivo nutritive value of the most promising linseed meal in diets containing either barley or corn-based concentrate. Canola meal (CM) and soybean meal (SBM) were included in the evaluative stage for comparative purposes. Linseed meals contained 37.8 and 35.4% crude protein (CP); 22.6 and 25.9% neutral detergent fibre (NDF); and 12.9 and 7.1% crude fat for ELM and SLM, respectively. Rate and extent of dry matter, NDF, and CP digestion, as determined by the rumen in situ technique, indicated that ruminal digestibility of SLM was similar to that observed for CM, but ruminal escape of ELM protein was higher than for CM. The proportion of ruminal escape protein was similar for SLM, CM and SBM. Total tract CP digestibilities of SLM and CM were similar to and lower than those observed for ELM and SBM. Soybean meal had the highest total tract CP digestibility. Based on results of the analytical and in situ procedures, SLM was selected for evaluation in the in vivo experiment. Results indicated that SLM did not have any deleterious effect on digestion of other components of the diet, and parameters of rumen fermentation indicated similar digestion patterns for cows fed SLM and CM. Overall, results indicate that SLM has potential as a replacement for CM or SBM in diets of dairy cattle. It was also concluded that replacement of barley with corn does not influence the nutritive value of SLM for dairy cows. Key words: Linseed meal, canola meal, dairy cattle
Evaluation of lathyrus (Lathyrus sativus L) as an ingredient in pig starter and grower diets
Authors: Castell A. G. , Cliplef R. L. , Briggs C. J. , Campbell C. G. , Bruni J. E.
Published: March 2010

Seed from Lathyrus sativus L., with a low content of β-N-oxalyl-L-α, β-diamino-propionic acid (ODAP), was evaluated as an ingredient (LM) in swine diets. The first experiment involved 45 pigs fed LM, containing 27% protein (CP) and 3 g ODAP kg−1, as 0, 10, 20, 30 and 40% of starter diets (20% CP) over a 6-wk period. In exp. 2, two types of LM (0.9 and 2.7 g ODAP kg−1) were each included as 0, 10, 20 and 30 of mash diets fed to 84 pigs from 25 to 100 kg liveweight. The effects of pelleting and supplementation with 1 and 2 g methionine kg−1, for LM diets containing < 0.5 g ODAP kg−1, were examined in the final experiment using 80 growing-finishing pigs. Increasing the LM content above 10% of the starter diet reduced average daily gains (ADG) and feed intake (ADFI) but feed conversion (gain/feed; G:F) was unaffected (P > 0.10). In exp. 2, ADG declined as the dietary content of either LM increased. The lower-ODAP LM-fed pigs had relatively higher ADFI (P < 0.01) and ADG (P < 0.05) but slightly lower G:F (P < 0.08). Consumption of lathyrus led to higher (P < 0.01) liver and kidney weights and lower (P < 0.05) protein content in the longissimus dorsi. Pelleting the diet improved ADG (P < 0.01) and G:F (P < 0.05) but did not prevent the LM-effect on growth rates. Increasing the total sulfur amino acid content of the diet from 0.48 to 0.66% had no beneficial effect on live or carcass measurements. Using a method capable of detecting 100 ng ODAP per g fresh tissue, no residues were found in the loin muscle of LM-fed pigs. The results suggest that anti-nutritive constituents (e.g. anti-trypsin and anti-chymotrypsin), rather than ODAP, limit the potential of lathyrus seed as a feedstuff for swine. Key words: Pig, lathyrus, growth, carcass, neurotoxin
Estimating water consumption and factors affecting intake in grazing cattle
Authors: Ali Shaukat , Goonewardene L. A. , Basarab J. A.
Published: March 2010

Water consumption (WC) by 39.5 animal units (AU) of grazing cattle was studied at a central Alberta site in summer. Average WC AU−1 was estimated at 48.9 L d−1. WC increased by 0.68 L AU−1 (P < 0.01) for each percentage decrease in relative humidity, increased by 0.81 L AU−1 (P < 0.02) for each degree Celsius increase in maximum daily temperature, and increased by 0.15 L AU−1 (P < 0.06) as cattle grew and the season progressed. Relative humidity is shown to be an important determinant of WC in grazing cattle. Key words: Water consumption, animal unit, temperature, humidity, grazing cattle
Relationship between expected progeny differences of Canadian Hereford sires and performance of their progeny in commercial herds
Authors: Basarab J. A. , Milligan D. , Stitt J.
Published: March 2010

Sire expected progeny differences (EPDs) for calf birth, weaning and yearling weight predicted genetic differences between progeny of sires. A 1-kg change in birth weight EPD corresponded to a 1.06 ± 0.14 kg (P < 0.001) change in actual calf birth weight. A 1-kg change in weaning weight EPD or yearling weight EPD corresponded to a 0.45 ± 0.18 kg (P = 0.012) change in 200-d weaning weight or a 0.78 ± 0.15 kg (P < 0.001) change in 365-d yearling weight. Calving ease EPD was not related (0.37 ± 0.27; P = 0.17) to calving ease score. Key words: EPD, calving ease, birth weight, weaning weight, yearling weight
Vitamin E and selenium in milk of ewes
Authors: Meneses A. , Batra T. R. , Hidiroglou M.
Published: March 2010

Eighteen ewes were randomly assigned to one of three treatment groups: control, injected vitamin E, and injected selenium, with the objective of evaluating the effect of these treatments on the concentration of vitamin E and selenium in the milk. Vitamin E injections were given by intramuscular injection at the rate of 2000 IU per ewe at lambing and at 6 wk after lambing. Selenium supplementation was given by intramuscular injection at the rate of 12 mg sodium selenite at lambing and at 5 wk after lambing. Milk samples from all ewes in the three groups were collected for determination of vitamin E and selenium 0, 1, 2, 7, 14, 21, 28, 35, 42, 49, and 56 d after lambing. Ewes injected with vitamin E or selenium at lambing increased the concentration of these nutrients in milk during the first 14 d of lactation; as a result, increased amounts of vitamin E and selenium were available to suckling lambs during their early days of life. Milk levels of selenium but not vitamin E were increased by subsequent injection of selenium or vitamin E, respectively. It was also observed that colostrum contained higher concentrations of both vitamin E and selenium than did whole milk. Key words: Vitamin E, Se, milk, ewes
The effect of feed type on mouth lesions in slaughter cattle
Authors: Karren D. B. , Goonewardene L. A. , Bradley J. A.
Published: March 2010

The incidence of tongue lesions in slaughter cattle was 19.1%. Although the incidence of lymph node enlargement was low, it was five times higher in cattle with tongue lesions. Carcass weights were not affected by the presence of mouth lesions. The incidence of lesions was significantly higher (P < 0.00001) for cattle finished on silage from semi-dwarf rough awn (29.3%) compared to normal stem rough awn (13.5%) and normal stem smooth awn (11.8%) barley. Key words: Incidence, lesions, tongue, barley, cattle.
Tissue vitamin E concentrations after single injection of α-tocopherol in pigs
Authors: Batra T. R. , Hidiroglou M.
Published: March 2010

Forty pigs were randomly assigned to one of the four treatment groups: control, 500 IU, 1500 IU, and 2500 IU of vitamin E given as a single intramuscular injection. Out of 40 pigs, 20 were slaughtered at day 3 and the remaining 20 at day 7 after injection. Effect of treatment was significant (P < 0.05) for vitamin E concentrations in all tissues. The effect of time of slaughter after the injection was significant (P < 0.05) for spleen, liver, kidney, lung, hip muscle and adrenal, while the interaction of treatment with time was significant (P < 0.05) for most of the tissues except adipose tissue and neck muscle. Concentration of α-tocopherol in all tissues increased with increased dose of injection. In most tissues, α-tocopherol concentration was higher at 3 d than at 7 d after injection. By 7 d, levels had dropped significantly but were still much higher than control levels. Intramuscular injection of vitamin E in pigs resulted in significant differences in tissue α-tocopherol concentrations. Key words: Vitamin E, tissues, pigs
Effect of different forms of polyunsaturated fatty acids on duodenal and serum fatty acid profiles in sheep
Authors: Enjalbert F. , Nicot M. C. , Griess D. , Vernay M. , Moncoulon R.
Published: March 2010

Four sheep cannulated in the rumen and proximal duodenum were used in a 4 × 4 cross-over design to investigate the effects of ruminal fatty acid (FA) infusion on duodenal and serum FA profiles. The diets were composed of 85.7% natural grassland hay and 8.6% concentrate supplemented with 5.7% soy oil for diet SO, 5.7% emulsified soy oil for diet ESO, 6.7% calcium salts of soy or palm FA for diets CaSSO and CaSP, respectively. Diets were formulated to be isonitrogenous and isoenergetic; total FA content in dry matter was 6.4–6.6%. Characteristics of ruminal fermentation were not affected by source or physical form of FA. The proportion of stearic acid in the duodenal flow (% of the total C18) was high compared with total diet, e.g., 49.8 vs. 3.5 and 54.3 vs. 9.4% for soy and palm diets, respectively. Ruminal biohydrogenation and unsaturated FA was lower for CaS diets than for SO and ESO diets (48.7 and 60.9 vs. 81.2 and 94.7%, for oleic and linoleic acids, respectively). As a result, trans-vaccenic acid levels in duodenal flow and serum (% or total FA) were lower for the CaS diets than for SO and ESO diets (8.3 vs. 36.0% and 0.9 vs. 7.8%, respectively). Unsaturated FA as CaS were partly protected against ruminal biohydrogenation, and can be effective in increasing intestinal absorption of unsaturated FA. Key words: Unsaturated fatty acids, soy oil, calcium salts, biohydrogenation, sheep
Post-weaning gain of calves from first-cross and reciprocal back-cross cows
Authors: Newman J. A. , Tong A. K.W. , Rahnefeld G. W. , Lawson J. E. , Fredeen H. T. , Weiss G. M.
Published: March 2010

Data on post-weaning gains and final test weights are reported for 2010 Limousin-sired steer and heifer calves from cows of 15 different F1 cross and back-cross breed types incorporating Charolais, Simmental, Hereford, Angus and Shorthorn breeding. Calves representing all 15 dam breed types were born and weaned under semi-intensive management at Brandon, Manitoba, then finished there on a self-fed all-concentrate diet. A subset representing eight dam breed crosses was born and weaned under extensive range management at Manyberries, Alberta, then fed at Lacombe, Alberta, on a lower energy diet of silage and concentrate mixed and fed to appetite in bunks. A comparison of common breed types revealed that the Brandon calves were lighter at weaning but gained more rapidly in the post-weaning test than the Manyberries/Lacombe calves. Under the Lacombe feeding regime, there were no significant differences in rate of gain on the feedlot test, but progeny of breed types containing some Simmental breeding generally reached a higher final weight than progeny of Hereford × Angus cows because of differences in weight at the beginning of the test. Under the higher energy feeding regime at Brandon, progeny of breed types containing Charolais or Simmental generally gained faster and attained higher final weights than progeny of Hereford × Angus cows. Progeny of Charolais × British and Simmental × British F1 cross cows generally performed as well as, or better than, the progeny of either backcross. Key words: Beef cattle, post-weaning gain, crossbred dam, back-cross dam, European cross
Characterization of Na+, K+ ATPase in erythrocytes of dairy cows: Effect of diet and genetic selection for milk solids
Authors: Scollan N. D. , Zhao X. , Brisbane J. R. , McBride B. W. , Jessop N. S. , Allan G. F. , Oldham J. D.
Published: March 2010

The number and activity of Na+, K+ ATPase units were assessed with 3H-ouabain binding and 86Rb+ uptake methods, respectively, in erythrocytes from second-parity Holstein–Friesian cows at weeks 10 and 24 of lactation. The cows were either from S or C genetic lines for yield of milk fat and protein and were offered diets of either H or L forage content. The Scatchard method of analysis indicated that 3H-ouabain binding was compatible with a single class of receptors of high affinity. S-line cows had higher milk yields (P < 0.001) than C-line animals at both sampling points. Those animals fed the low-forage feed had higher levels of dry matter intake (P < 0.001) and milk yields (P < 0.001) at weeks 10 and 24 than contemporaries fed the high-forage feed. Main effects of genetic line and diet were not significant for dissociation-rate constants (Kd) and the number and activity of Na+, K+ ATPase units. The number of enzyme units was higher at week 24 than at week 10 (P < 0.1), and between-cow variation was significant for the number of enzyme units (P < 0.02). A significant genetic line × diet interaction for enzyme activity at weeks 10 and 24 was detected (P < 0.10). This was particularly pertinent at week 10, when activity was greatest for groups CH and SL and least for groups CL and SH. The reduction in ouabain-sensitive 86Rb+ uptake for groups CL and SH may reflect an imbalance between genotype and nutrient provision. Positive relationships were found between the number and activity of Na+, K+ ATPase units and the milk energy output (P < 0.1 and P < 0.01, respectively). This may reflect the increased demand in Na+, K+ pumping that is required for enhanced milk productivity and suggests that the activity of erythrocyte Na+, K+ ATPase reflects the activity of this enzyme in other tissues during lactation. Key words: Dairy cows, genotype, diet, erythrocyte, Na+, K+ ATPase
Phosphorus-31 nuclear magnetic resonance spectroscopy of liver from two broiler chicken lines
Authors: Liu Z. , McBride B. W. , Lirette A. , Fairfull R. W. , Brauer M.
Published: March 2010

Hepatic levels of phosphorus-containing compounds that are related to fat metabolism in the liver of two broiler lines with different body-fat content were assessed using high-resolution 31P NMR spectroscopy. PCA extracts of livers from 16-d-old chicks were analyzed with an NMR spectrometer. The results demonstrated that the concentrations of G3P, AMP and phosphocholine were significantly higher in the livers of LL birds than in those of the FL birds (P < 0.05). Differences in hepatic concentration of GPE and GPC were not detected between the two lines. It was also found that the liver weight per unit body weight of the FL chickens was less than that of the LL birds (P < 0.01). Average body weight of FL birds at 16 d of age was lighter than that of LL birds (P = 0.01). The FL birds deposited more (P < 0.05) fat per unit body weight than the LL birds. However, no statistical difference (P > 0.05) was found in protein deposition per unit body weight between the two lines. These results indicate that liver size and the concentration of hepatic phosphorus containing compounds are related to the partition of energy in broiler chickens. Key words: NMR spectroscopy, phosphorus-containing compounds, fat deposition, liver, broiler chicken
Mammary-derived growth inhibitor in bovine milk: Effect of milking frequency and somatotropin administration
Authors: Stelwagen K. , Davis S. R. , Farr V. C. , Politis I. , Guo M. R. , Kindstedt P. S.
Published: March 2010

The effects of milking frequency and exogenous somatotropin on milk MDGI were investigated in cows. High levels of MDGI in milk were found during lactation; however, despite significant changes in milk yield, neither milking frequency nor somatotropin affected MDGI. The data do not support a role for MDGI in acute regulation of mammary synthetic ability. Key words: Milking frequency, somatotropin, MDGI, bovine, lactation, differentiation
Effects of microbial inoculant and moisture content on preservation and quality of round baled alfalfa
Authors: Mir Z. , Mir P. S. , Jan E. Z. , McCartney D. H. , Robertson J. A.
Published: March 2010

The effects of microbial inoculant and moisture content of alfalfa, stored as large round bales, on preservation and quality were examined in a 3-yr study. Alfalfa was round baled at 18, 45 and 60% moisture with 45 and 60% moisture bales stored in 23-m-long plastic tubes. At each moisture level, half the bales were treated with a microbial inoculant (Lactobacillus plantarum) during baling. All bales were weighed and sampled prior to storage (into storage) and prior to feeding (out of storage) with a core sampler. Field recovery and crude protein content of forage at 18% moisture were significantly lower than for forage at 45 and 60% moisture levels. ADF contents were decreased (P < 0.01) by moisture content in year 1, while the NDF contents were affected similarly in all the 3 yr. Storage recoveries were not affected by either moisture content or inoculant. Nutritive value of forages was evaluated, using completely randomized designs, in feeding trials with 96 steers and digestibility trials with 36 wethers. Dry matter intake by steers and nutrient digestibility in sheep were not affected (P < 0.05) by either moisture level or inoculant treatment. Feed conversion efficiencies and average daily gain of steers receiving 45 and 60% moisture forage were higher than for those fed 18% moisture forage. Results from this study indicated that harvesting alfalfa at 45 and 60% moisture as silage produced a better-quality product for steers than at 18% moisture dry hay and that treatment with microbial inoculant was not beneficial in preserving high moisture forage. Key words: Alfalfa, large round bales, inoculant, silage, steer, sheep, digestibility, hay
Effects of metabolic hormones and growth factors on forskolin and dibutyryl adenosine 3′,5′-cyclic monophosphate induced steroidogenic responses by porcine granulosa cells in vitro
Authors: Xu Y. , Kirkwood R. N. , Thacker P. A. , Rajkumar K.
Published: March 2010

The present experiments were conducted to examine the influence of metabolic hormones and growth factors on progesterone and estradiol secretion by porcine granulosa cells in culture and to determine the possible site(s) of action of these agents on steroidogenesis. Porcine granulosa cells, obtained from medium-sized (4–6 mm) nonatretic follicles of prepubertal gilts slaughtered at a commercial abattoir, were cultured at a density of 2 × 106 viable cells well−1 in serum-free Eagle's Minumum Essential Medium for 72 h with 0, 10 or 100 ng mL−1 of GH, insulin or IGF-I or IGF-II. At 72 h, each treatment group was divided into three subgroups, one subgroup remained untreated (basal) while either 25 μM FK or 3 mM dbcAMP was added to the other two subgroups. Additionally, androstenedione (10−7 M) was provided to all cultures as a substrate for estradiol biosynthesis. Media were collected at 96 h for determination of progesterone and estradiol content. Both IGF-I and IGF-II increased (P < 0.01) basal progesterone and estradiol secretion and enhanced the FK- and dbcAMP-induced stimulation of progesterone and estradiol secretion (P < 0.01). Insulin, at 100 ng mL−1, had a modest but significant positive effect on both FK- and dbcAMP-stimulated steroidogenic responses. In contrast, GH inhibited basal, FK- and dbcAMP-induced progesterone and estradiol production. Based on the stimulatory effects of both IGFs above those seen with dbcAMP alone and the inhibitory effects of GH in the face of dbcAMP stimulation, we conclude that their effects are likely mediated by non-cAMP dependent pathways. Key words: Steroidogenesis, granulosa cells, growth hormone, IGF, insulin, pigs
Characterization of embryonic oxygen consumption of two broiler chicken lines differing in body fat content
Authors: Liu Z. , McBride B. W. , Lirette A. , Chambers J. R.
Published: March 2010

Eggs of two broiler chicken lines differing in body fat content were incubated and oxygen consumption of single embryos was measured on days 14–19 of incubation with an indirect calorimeter. The objectives of this study were to investigate oxygen consumption patterns of the two genetic lines in the late stage of embryonic development (days 14–19) and the relationship between this pattern and body composition of the bird at 8 wk of age. Oxygen consumption for the genetically lean line (LL) was higher (P < 0.05) than that for the genetically fat line (FL) for days 14 and 15 of incubation, while no differences were detectable after day 16 of incubation. The average oxygen consumption over the 6 d of measurement tended to be higher (P = 0.09) for LL than for FL. Furthermore, male embryos had a higher (P < 0.05) O2 consumption rate after day 17 of incubation than female embryos. The average O2 consumption rate over the 6 d of measurement tended to be higher (P = 0.07) for males than for females across genetic lines. At 8 wk of age, FL birds had greater (P < 0.01) body fat content than LL birds. Also, females showed a greater body fat content than males. Statistical analysis indicated that body fat content and body weight at 8-wk of age were correlated with embryonic O2 consumption. However, the correlation between body weight and embryonic O2 consumption was higher than that between body fat content and embryonic O2 consumption, which would be expected since oxygen consumption reflects lean body mass. Key words: Oxygen consumption, embryo, broiler, fat content, indirect calorimetry
Effects of adaptation to lasalocid, monensin or a daily rotation of lasalocid and monensin on in vitro fermentation of a 90% concentrate diet
Authors: Duff G. C. , Galyean M. L. , Branine M. E.
Published: March 2010

Effects of adaptation to L, M or a daily rotation of L and M (R) on in vitro fermentation were measured in a replicated in vitro experiment with a 4 × 4 factorial arrangement of treatments. Treatments were adaptation of ruminal fluid donor steers (0 or 200 mg steer−1 d−1 of L, M or R) and culture ionophore treatment (0 or 4 μg mL−1 of L, M or a 50:50 mixture of L and M). At 12 and 24 h, IVDMD was increased (P < 0.05) by adaptation to L compared with M, and decreased at 12 h (P < 0.05) by adaptation to R compared with the average of L and M adaptation. At 6 and 12 h, culture ionophore treatments increased (P < 0.10) IVDMD, compared with control. After 24 and 48 h of in vitro incubation, L adaptation increased (P < 0.01) acetate, decreased (P < 0.01) propionate, increased the acetate/propionate ratio (P < 0.01), and increased total VF A (P < 0.05), compared with M adaptation. Total VFA was increased (P < 0.10) for ionophore adaptation treatments compared with control at 48 h of incubation. Culture ionophore treatments decreased (P < 0.10) acetate and increased (P < 0.05) propionate at 24 and 48 h and decreased the acetate/propionate ratio (P < 0.10) at 24 h of incubation versus control cultures, with no measurable effects on total VFA. Adaptation treatments did not interact with culture treatments, suggesting that animals used as inoculum donors for in vitro experiments involving ionophores need not be adapted to an ionophore. Key words: In vitro, fermentation, ionophores, monensin, lasalocid
Effect of feeding fermented, ammoniated, condensed whey permeate on intake, digestibility, rumen fermentation, and acid-base balance in sheep
Authors: Boukila B. , Seoane J. R. , Bernier J. F. , Goulet J. , Petit H. V.
Published: March 2010

Nine DLS rumen-cannulated wethers (69 kg avg BW) were used to study the effects of dietary supplementation with two types of fermented, ammoniated, condensed whey permeate on performance, rumen physiology and acid-base status in sheep fed high-grain diets. Sheep were fed three isonitrogenous (16% CP) diets according to a triple 3 × 3 Latin square design, with three 21-d periods each. One whey permeate contained ammonium lactate (AL) while the other contained ammonium propionate (AP). Urea was used as a source of NPN in the control diet (C). Diets, offered ad libitum, contained 78% barley and 18% dehydrated alfalfa meal. Dry matter and digestible energy intakes were about 15% higher for diets AL and AP than for diet C (P < 0.05). Dry matter digestibility was not affected by the treatments, whereas organic matter and energy digestibilities tended to be higher for diet AP than for diet AL (P < 0.07). Rumen fermentation was not affected by the treatments. Over a 4-h post-feeding period, sheep fed diet C had higher plasma concentrations of lactate (P < 0.06) and acetate (P < 0.04) but lower levels of plasma propionate (P < 0.06) than sheep fed the AL and AP diets. Plasma propionate 2 h after feeding was higher in sheep fed the AL diet versus the AP diet (P < 0.01). Sheep blood was mildly alkalotic despite the fact that sheep were fed a high-grain diet. The two types of fermented, ammoniated and condensed whey permeate were found to be good sources of NPN. Key words: Whey, rumen fermentation, acid-base balance, sheep
Effects of abomasal slaframine infusion on ruminal digesta passage and digestion in steers
Authors: Froetschel M. A. , Streeter M. N. , Amos H. E. , Croom Jr. W. J. , Hagler Jr. W. M.
Published: March 2010

Slaframine was infused intra-abomasally once daily 3 h after feeding to four ruminally and abomasally cannulated Jersey steers (586 ± 88.6 kg) at 0 (saline control), 10, 20, or 30 μg kg−1 BW in a 4 × 4 Latin square design experiment. Periods were 14 d in length. On a DM basis, diets were a 38:62, sorghum silage: concentrate offered at 125% of the net energy required for maintenance. Ruminal, abomasal, and fecal samples were collected at 2-h intervals on days 10–12, and ruminal contents were completely evacuated and sampled at 3, 6, 12, and 24 h after feeding on days 13 and 14. Ruminal volume and pH increased (linear; P < 0.05) from 1.6 to 8.9% and from 0.10 to 0.22 units, respectively, with SF. Total ruminal VFA and ammonia concentrations decreased (linear; P < 0.05) with SF from 4.1 to 9.4% and from 5.3 to 10.2%, respectively. Apparent ruminal DM and starch digestion increased at the lowest dosage and decreased at higher dosages of SF (quadratic; P < 0.05). Ruminal NDF digestion decreased with SF (linear; P < 0.1). Totat tract DM digestion was not affected by SF. Fractional turnover rate of ruminal DM increased (linear; P < 0.05) from 1.6 to 11.3% with SF. During the first 8 h after SF administration, liquid dilution rate increased as much as 18.5% with the highest dosage of SF (linear; P < 0.05). During the 10– to 21-h period after SF administration, dilution rate decreased with the 10– to 20-μg kg−1 BW dosages of SF (quadratic, P < 0.05). Outflow of AA tended to decrease at 10 and 20 and increased at the 30 μg kg−1 BW dosages of SF (quadratic, P < 0.05). Abomasal infusion of SF alters digesta passage and the site of digestion of nutrients between the rumen and the lower digestive tract. The highest level shifted the site of digestion to the lower tract while lower dosages enhanced ruminal digestion. Key words: Rumen fermentation, digestion, passage, muscarinic, cholinergic