bluuebunny/crossref_metadata_2025 huggingface dataset:
LIVEWEIGHT, PROTEIN DEPOSITION AND DIGESTIBILITY RESPONSES IN GROWING PIGS EXPOSED TO LOW TEMPERATURE
Authors: PHILLIPS P. A. , YOUNG B. A. , McQUITTY J. B.
Published: March 2010

Two groups of eight individually caged female pigs, averaging 45 kg liveweight, were exposed alternately for 15-day periods to 21 and 6 °C for four consecutive periods. Four pigs in each group were restricted to 100 g of feed per unit of metabolic body weight and four were fed ad libitum. From regressions of liveweight vs. time for the last 10 days of each period, low temperature (6 °C) was found to reduce average daily gain by 2.3% per degree Centigrade below the rate of 792 g/day measured at 21 °C. Also, transitory liveweight changes were measured during the 5 days after each temperature changeover. With each temperature decrease (21 – 6 °C), there was a mean temporary loss in liveweight of 4% and with each temperature increase (6 – 21 °C), this temporary loss of 4% of liveweight was regained, at a constant level of feeding. While exposed to 6 °C, the digestibility of ration dry matter, energy and nitrogen (78.2%, 77.0% and 74.7%, respectively) was significantly lower than when pigs were exposed to 21 °C (80.8%, 79.9% and 79.4%, respectively). As a result of these findings, estimated changes in weight of gutfill were calculated from fecal output records. Regression analysis indicated that changes in gutfill could be responsible for about 55% of the observed temporary liveweight changes. Nitrogen balance data indicated that protein energy retention rates decreased by 1.0% per Celsius unit below the rate of 150 kJ/(day∙kg0.75) measured at 21 °C. The ratio of protein gain to total weight gain was, on average, 25% larger at 6 °C, compared to that measured at 21 °C, indicating leaner growth at low temperature. The effects of feeding level were small compared to the effects of temperature. Key words: Liveweight, protein, digestibility response, pigs, temperature
MODELLING PROTEIN AND LIPID GAINS IN GROWING PIGS EXPOSED TO LOW TEMPERATURE
Authors: PHILLIPS P. A. , MacHARDY F. V.
Published: March 2010

An existing energy partition model that relates protein and lipid retention in growing pigs (60 kg) to dietary energy intake was extended to include environmental temperature. The extended model for 45- to 75-kg pigs can be used to predict animal heat production at each feeding level, lower limit of the zone of thermoneutrality at each feeding level and incremental energy conversion efficiency over a range of feeding levels and environmental temperatures. The model predictions were validated in two ways. (1) Incremental energy conversion efficiencies over a range of feeding levels and environmental temperatures, as determined in three studies cited in the literature, were compared against the energy conversion efficiencies predicted by the model. (2) The rates of protein deposition and liveweight gains in growing pigs housed at 21 °C and 6 °C, were compared against the model predictions. While the model should receive further testing, both the above tests confirmed that low temperature can be related to feeding level and rates of tissue gain in pigs in a predictable manner. Key words: Pig, temperature, model, energy retention
ROLE OF NA+, K+-ATPase IN MUSCULAR ENERGY EXPENDITURE OF WARM- AND COLD-EXPOSED SHEEP
Authors: GREGG V. A. , MILLIGAN L. P.
Published: March 2010

The role of Na+, K+-ATPase in the energy expenditure of sheep skeletal muscle and the influence of exposure to cold on this role were studied. An in vitro preparation of muscle was developed that achieved O2 availability and a functional membrane potential. A 10−6 M concentration of ouabain yielded a maximum inhibition of respiration of 38.9 ± 1.8% using muscle preparations from a random group of sheep. Whole body and muscle O2 consumptions and ouabain-sensitive muscle respiration were measured for warm- and cold-exposed sheep fed at maintenance or 1150 g of alfalfa pellets per day. Cold exposure increased whole body and muscle O2 consumption. Inhibition of respiration by ouabain was 37.6 ± 1.2% and 41.0 ± 3.6% for warm- and cold-exposed sheep fed at maintenance, and 28.5 ± 4.0% and 45.0 ± 4.0% for warm- and cold-exposed sheep fed 1150 g of alfalfa pellets per day. The increase in the ouabain-sensitive component of respiration accounted for 48–79% of the increased O2 consumption of muscle from cold-exposed sheep. It was concluded that the Na+, K+-ATPase of sheep muscle is a major means of energy expenditure and has an important role in the increased thermogenesis resulting from cold exposure. Key words: Skeletal muscle, Energy expenditure, muscle respiration, cold thermogenesis, sodium-potassium transport
PRESERVATION AND FEEDING VALUE FOR YEARLING STEERS OF WHOLE PLANT CORN ENSILED AT 28 AND 42% DRY MATTER WITH AND WITHOUT COLD FLOW AMMONIA TREATMENT
Authors: BUCHANAN-SMITH J. G.
Published: March 2010

Corn was ensiled at both 28 and 40% dry matter (DM) with and without prior treatment of anhydrous ammonia using the cold-flow technique. Crude protein of treated silage was from 3.37 to 3.82% units higher than untreated silage. Lactic and acetic acid levels and pH were greater in treated than in untreated silage. As true protein-N was greater in ammonia-treated than untreated silage by between 0.09 and 0.23 percentage units, DM basis, and amine-N was correspondingly decreased, a significant inhibitory effect of ammonia on degradation of corn protein was observed. In a 112-day feeding trial utilizing 96 yearling Charolais × steers (mean weight, 300 kg), ammonia treatment of corn silage improved intake by 5% and gain by 6% over untreated corn silage supplemented with urea at feeding time. Intake of high dry matter corn was 5% greater than that of the lower dry matter corn, but gain was unaffected by corn dry matter. Ammonia treatment significantly improved aerobic stability of both corn silages. Effluent losses caused a 10% unit reduction in recovery of dry matter from 28% DM compared to 40% DM corn and ammonia treatment had no pronounced effect upon nutrient losses during ensiling. Significance of these results for effective preservation of corn silage and the relevance of protein degradation to the nutritive value of corn silage are discussed. Key words: Corn silage, yearling steers, dry matter level, analytical effects, amonia treatmeet
KINETICS OF INTRAVENOUSLY ADMINISTERED CALCIUM-47 IN SHEEP
Authors: HIDIROGLOU M. , HIDIROGLOU M. A.
Published: March 2010

This report describes studies of calcium kinetics in 18 sheep administered calcium-47 intravenously. The animals were divided into three groups before dosing with label: Group I, control; Group II received a single 106 IU dose of vitamin D3 intramuscularly 8 days prior to injection of the label; Group III received a single dose of 1 mg 25-hydroxyvitamin D3 intramuscularly 3 days prior to the label injection. Both vitamin D3 and its metabolite, 25-hydroxyvitamin D3, increased plasma calcium levels for the entire 72-h experimental period. The kinetic data were satisfied by a model with two exchanging compartments. Individual and mean values for these kinetic analyses are presented with their statistical analyses. In the sheep injected with 25-hydroxyvitamin D3 there was a tendency for higher rate of exchange of calcium-47 between compartments. Key words: Calcium, kinetic data, sheep
CHANGES IN AMMONIA CONCENTRATION, BACTERIAL COUNTS, pH AND VOLATILE FATTY ACID CONCENTRATION IN RUMEN OF COWS FED ALFALFA HAY OR CONCENTRATE: UREA-CORN SILAGE
Authors: MAHADEVAN S. , SAUER F. D. , ERFLE J. D. , TEATHER R. M. , MORSE P. M.
Published: March 2010

Four rumen-fistulated cows were fed alfalfa hay (15.4% CP) ad libitum for 4 wk prior to the experiment and from day 1 to day 8 of the experiment. From days 9 to 15 (period 2) and from days 16 to 39 (period 3) they were fed ad libitum concentrate: urea-corn silage (15.9% CP). Rumen fluid samples were collected from 0600 to 1600 h during the three periods and changes in the pH, concentrations of ammonia and volatile fatty acids (VFA) and bacterial counts were determined. Ammonia, pH and VFA concentrations showed oscillatory behavior even on an ad libitum feeding schedule. Rates of production and utilization of ammonia were significantly higher with the concentrate: urea-corn silage diet than with the hay diet. VFA concentration and pH were inversely related. Periods of high VFA production coincided with periods of rapid ammonia utilization. The evidence indicated that there was a metabolic adaptation in the rumen for better utilization of ammonia. Concentrations of amino acids and peptides were nearly 1 mM in the rumen fluid throughout the day and increased to 3 mM immediately after feeding. Most of the increases were due to alanine, leucine and aspartic acid. It is concluded that the practice in nutritional studies of measuring and reporting rumen ammonia, VFA and pH only once at one time point in an experiment or even the mean of several determinations does not adequately represent the complex metabolic changes in the rumen. Key words: rumen, ammonia, fermentation, pH, adaptation, amino acids
INFLUENCE OF CALF GENETIC TYPE ON PREWEANING TRAITS UNDER COMMERCIAL BEEF CATTLE CONDITIONS
Authors: AARON D. K. , THRIFT F. A.
Published: March 2010

Birth and weaning weight data were evaluated on 1/2 Simmental (SH, SA), 1/2 Maine-Anjou (MH, MA), 3/4 Simmental (S.SH, S.SA) and 3/4 Maine-Anjou (M.MH, M.MA) calves. For birth weight, 1/2 Simmental calves were lighter (P < 0.01) than 1/2 Maine-Anjou calves, and calves from Hereford cows were heavier (P < 0.01) than calves from Angus cows. Also, S.SH calves were heavier (P < 0.01) than S.SA calves. For weaning weight, 3/4 Simmental calves were heavier (P < 0.01) than 3/4 Maine-Anjou calves, and 1/2 Simmental and Maine-Anjou calves were lighter (P < 0.01) than 3/4 Simmental and Maine-Anjou calves. Key words: Calf genetic types, grading-up, beef cattle
EFFECT OF DOSE OF PREGNANT MARES' SERUM GONADOTROPHIN ON THE REPRODUCTIVE PERFORMANCE OF EWES SYNCHRONIZED FOR ESTRUS AND HOUSED IN TOTAL CONFINEMENT
Authors: HACKETT A. J.
Published: March 2010

Ewes housed indoors year round were treated with 40 mg of fluorogestone acetate followed by 0, 250, 500 or 750 IU pregnant mares' serum gonadotrophin (PMSG). PMSG did not enhance fertility, prolificacy or fecundity in ewes bred at the synchronized estrus. Key words: Sheep, PMSG, synchronization, fertility, prolificacy, fecundity
SUBSTITUTION OF SORGHUM FOR WHEAT IN DIETS FOR LAYING HENS
Authors: GARDINER E. E. , MAJOR D. J. , DUBETZ S.
Published: March 2010

The effects of substituting various levels of sorghum for wheat in diets for laying hens were studied. Egg production, egg weight, feed consumption, body weight and hatchability of eggs from Single Comb White Leghorn hens were not affected by the proportion of sorghum in the diet. Key words: Sorghum, wheat, nutrition, egg production
EFFECT OF STARVATION AND FORCE FEEDING ON BODY WEIGHT RECOVERY TIME OF ADULT ROOSTERS
Authors: SCHANG M. J. , LEESON S. , SUMMERS J. D.
Published: March 2010

Body weight losses of adult cockerels, during a simulated true metabolizable energy (TME) bioassay were measured. All birds retained their initial weights within 8 days when fed ad libitum. The results confirm the adequacy of a 12-day interval between TME assays. Key words: True metabolizable energy, body weight recovery, force-feeding, starvation, roosters
DAIRY HERD GENETIC DIFFERENCES FOR LACTATION PRODUCTION
Authors: SCHAEFFER L. R. , KERR A. , BURNSIDE E. B.
Published: March 2010

Cow estimated transmitting abilities (ETA) for milk yield and fat percent derived by best linear unbiased prediction methods were used to compute averages for each herd and year of calving subclass for herds enrolled on the Record of Production program (ROP). Means and variances of herd averages were tabulated according to province, herd size, and year of calving. The genetic trends in herd averages within herd size categories were positive for milk yields and negative for fat percent. The variance of herd averages has increased since 1958 within herd size categories, but has decreased over all herds due to a shift in size of herds since 1958. Herds with fewer than 20 cows represented 31.7% of the ROP herds in Canada in 1977 while in 1958 they represented 72.4%. However, in 1977 the larger herds did not show any genetic advantage over smaller herds. Ontario herds of size 20–9 cows showed greater variability in average ETA for milk and fat percent than herds in other provinces. Correlations among traits on a herd average basis have not changed in the last 10 yr even though herd averages have changed substantially over the same period. Herd genetic differences accounted for only 2.05% of herd phenotypic variance for milk yield and 12.74% for fat percent. Key words: Genetic differences, herds, cow indexing
FACTORS INFLUENCING CALVING PERFORMANCE IN RANGE BEEF CATTLE
Authors: MAKARECHIAN M. , BERG R. T. , WEINGARDT R.
Published: March 2010

Data from 2964 calving records of cows of all age groups and 1035 calving records of 2-yr-old heifers from three breeding groups (B), Hereford (HE), Beef Synthetic (SY) and Crossbred (XB) maintained at the University of Alberta Ranch at Kinsella were analyzed by the least squares method. Dam weight at calving (DAMWT), age of dam (A), calf birth weight CBWT, sire and dam birth weights and the interactions between A and CBWT, B and A, sex (S) and A and finally B and CBWT had significant influences on calving performance when calving records of all age groups were considered. Among heifers the effects of DAMWT, CBWT, B, S, dam birth weight and interaction between B and DAMWT were significant. DAMWT and CBWT were among the most important factors influencing calving performance. CBWT had a major influence in 2-yr-old dams with no noticeable influence in other age groups. Calving performance score of HE heifers was lower than those from XB and SY heifers, but breed group differences were minor at other age groups. Similarly males had more difficult births than female calves from young dams with no detectable sex influence from older dams. DAMWT had a greater positive impact on calving performance of HE heifers compared with the other two breeding groups. These interactions emphasize the importance of interrelationships of major factors influencing the incidence of dystocia in beef cattle. Key words: Factors, calving difficulty, beef cattle
EFFECTS OF PRERIGOR CHILLING AND FREEZING AND SUBCUTANEOUS FAT COVER UPON THE HISTOLOGICAL AND SHEAR PROPERTIES OF BOVINE LONGISSIMUS DORSI MUSCLE
Authors: JEREMIAH L. E. , MARTIN A. H.
Published: March 2010

A total of 119 bovine carcasses were utilized in three separate but related experiments to evaluate histological and textural parameters of the longissimus dorsi muscle at 45 min postmortem (unchilled), at 90 min postmortem (45 min cooler chill) and after a 24-h chill in a cooler at 2 °C. Samples were also examined after prerigor (90 min postmortem) freezing at −18 °C and subsequent slow thawing (24 h at 2 °C). The composite results of these experiments provide no evidence that conventional chilling of carcasses, with a subcutaneous fat cover of 4.57–19.56 mm at the eleventh thoracic vertebra, produced detrimental effects (P < 0.05) upon certain histological or textural properties of bovine longissimus dorsi muscle. However, prerigor freezing and subsequent thawing produced substantial (P < 0.05) effects on the susceptibility of fibers to fragmentation and incidence of wavy fibers, but did not produce detrimental effects (P > 0.05) on tenderness under the conditions imposed in the present study. The results from the present study also demonstrated that the issues involved in the transition of muscle to meat are far from resolved, and that additional research will be required to document fully the relevance of carcass chilling and meat handling procedures to meat quality. Key words: Beef, histological properties, shear values, prerigor chilling, prerigor freezing, fat cover
THYROID HORMONE CONCENTRATIONS: SOME KINETIC PARAMETERS OF TRIIODOTHYRONINE AND METABOLIC RATE IN 'DOUBLE-MUSCLED' CATTLE
Authors: STRATH R. A. , BASARAB J. A. , THOMPSON J. R. , BERG R. T.
Published: March 2010

Serum triiodothyronine (T3) and thyroxine (T4) concentrations were determined in 43 cattle of a Beef Synthetic (SY) breed group and 44 cattle of a 'double-muscled' (DM) breed group at the University of Alberta. Animals within the DM breed group were categorized as phenotypically normal, moderate or extreme based on the degree of phenotypic expression of the 'double-muscling' trait. Serum T3 concentration was significantly influenced by the degree of phenotypic expression of the double-muscling trait with phenotypically extreme-muscled DM animals demonstrating an increased T3 concentration as compared with phenotypically normal DM and SY cattle. Serum T3 concentrations in the phenotypically moderate-muscled DM cattle were intermediate. A nonsignificant trend was observed for the phenotypically extreme-muscled DM cattle to have an elevated serum T4 concentration as compared with the other phenotypes. The phenotypically moderate-muscled DM and normal SY cattle tended to be intermediate to phenotypically extreme- and normal-muscled DM cattle in serum T4 concentrations. In another study, some kinetic parameters of T3 were determined in three normal- to moderate-muscled, 19-mo-old DM bulls and three of their extreme-muscled DM half-siblings. The extreme DM cattle exhibited a significantly increased T3 pool size and a trend towards an increased T3 irreversible loss as compared with their half-siblings. The total T3 entry rates in extreme DM cattle and normal- to moderate-muscled cattle were not observed to be significantly different. The metabolic rate of four normal- to moderate-muscled DM bulls and four of their extreme-muscled DM half-siblings were compared. The metabolic rate of the extreme-muscled DM cattle was significantly (P < 0.05) higher than that of their half-sibling carriers. The increased serum T3 concentration, the larger T3 pool size and the elevated irreversible loss combined with the higher metabolic rate in the extreme DM cattle suggest that this heavily muscled animal type is relatively hyperthyroid. Key words: Thyroxine, triiodothyronine, metabolic rate, double-muscling, cattle
SUBSTRATE METABOLISM AND INTERRELATIONSHIPS IN THE OVINE FETUS IN UTERO
Authors: KITTS D. D. , KRISHNAMURTI C. R.
Published: March 2010

The kinetic parameters of substrate metabolism in the ovine fetus in utero were studied using isotope dilution techniques. The irreversible disposal rates of glucose, lactate and alanine following single injection of 14C-labelled substates are 2.94 ± 0.21 (n = 15), 2.58 ± 0.18 (n = 8), and 2.02 ± 0.34 (n = 10) mgC∙min−1∙kg−1, respectively. There is a positive correlation between glucose irreversible disposal rates and blood concentrations. The extent of glucose recirculation using 3[H] and [14C] glucose is 12.6 ± 5.5% of the irreversible disposal rate. The extent of glucose irreversible rate converted to lactate is 36 ± 4%. Recycling, which represents the re-entry of the label into the fetal circulation in its original form after sojourn in some other compartment, is an important feature of glucose, lactate and alanine metabolism in the fetus, occurring to an extent of approximately 70 – 85% of their total turnover rate. Lactate radioactivity could not be detected in the maternal blood following lactate injection into the fetus. On the other hand, approximately 52% of the fetal irreversible rate of glucose is returned to the maternal circulation. The conversion of alanine to glucose and lactate occurred to an extent of 8.9 and 35%, respectively, of its irreversible disposal rate. There was no incorporation of lactate label into fetal glucose when 14C-lactate was injected into the fetus. Key words: Glucose, lactate, alanine, metabolism, isotope dilution technique, fetus-in utero-substrate interrelationship
MEASUREMENT OF CARBON DIOXIDE PRODUCTION AND SUBSTRATE OXIDATION BY THE OVINE FETUS IN UTERO USING 14C-LABELLED COMPOUNDS
Authors: KITTS D. D. , KRISHNAMURTI C. R.
Published: March 2010

The irreversible disposal rate of CO2 in the chronically catheterized ovine fetus as determined by a primed dose-continuous infusion of NaH14CO3 was 13.5 ± 1.1 mL∙min−1∙kg−1 of fetus. After single injections of 14C-labelled substrates, the fraction of substrate carbon that was oxidized was determined from the specific activity patterns of the product and precursor. It was found that glucose, lactate, alanine and acetate were oxidized to an extent of 30.7, 36.1, 26.9 and 15.8%, respectively. The percent CO2 derived from the oxidation of glucose and lactate was 15.2 and 14.0, respectively. The fact that only 40% of total CO2 production can be accounted for by the oxidation of substrates studied raises the question whether other substrates are involved in the oxidative metabolism of the fetus. A quantitative description of the contribution of substrates to oxidative metabolism in the ovine fetus is therefore required. Key words: CO2 production, substrate oxidation, ovine fetus
EFFECTS OF VITAMIN B12 ON SERUM LIPIDS AND LIPOPROTEINS OF PIGS FED DIETS SUPPLEMENTED WITH PROPIONIC ACID OR CALCIUM PROPIONATE
Authors: THACKER P.A. , BOWLAND J.P. , FENTON M.
Published: March 2010

Effects of vitamin B12 supplementation of diets containing propionic acid (PA), or calcium propionate (CP) on feed intake, serum lipids and lipoproteins were studied utilizing 80 crossbred pigs averaging 22.5 kg. Diets, based on barley-soybean meal, containing 0, 3.5 or 7% PA or CP, were fed with and without the addition of 4.95 mg vitamin B12/kg diet. Inclusion of PA or CP with or without the addition of vitamin B12 had no significant effect on feed intake. Addition of PA or CP depressed serum cholesterol, high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol and serum triglycerides. Vitamin B12 supplementation had no effect on serum total cholesterol or HDL cholesterol, caused a reduction in LDL cholesterol, and tended to overcome the reduction in serum triglyceride. Supplementation of diets with vitamin B12 reduced liver lipid levels, largely as a result of a decrease in cholesterol and phospholipids. These data suggest that the cholesterol-lowering effect of PA is not simply a result of a depression in feed intake, but arises from a direct action of PA on cholesterol metabolism. Key words: Vitamin B12, lipids, lipo protein, pigs, propionic, propionate
EFFECTS OF SEX, GENOTYPE AND NUTRITION ON THE RELATIVE GROWTH OF MUSCLES IN THE PIG
Authors: RICHMOND R. J. , BERG R. T.
Published: March 2010

The effects of liveweight, breed, sex, diet and feeding level on muscle distribution were studied by comparing nine anatomical muscle groups dissected from the half carcasses of pigs from two studies. The first study consisted of 109 pigs representing barrows and gilts of three breed groups, fed two diets differing in energy and protein. The second study consisted of 72 barrows and gilts from two breed groups fed a low-energy diet at one of three feed levels. Animals were slaughtered at 23, 68, 91 or 114 kg liveweight. The results were compared with data from one other study. In pigs, major differentiation in muscle development appears to take place prior to 23 kg liveweight. Muscle differentiation appeared to follow functional demands. Muscles associated with mobility immediately after birth such as the distal limb muscles, developed early while those associated with greater locomotion and propulsion, such as the proximal pelvic limb muscles, developed later in life. Sex had little influence on muscle distribution between 23 and 114 kg liveweight. Proportion of abdominal muscles had apparently increased markedly prior to 23 kg liveweight and continued to be influenced by the level of feeding throughout. Breed differences in muscle distribution were observed for spinal, abdominal and distal thoracic limb muscles. Key words: Swine, muscle growth, muscle distribution
HOURLY DISTRIBUTION OF TIME OF PARTURITION IN BEEF COWS
Authors: YARNEY T. A. , PARKER R. J. , PALMER W. M. , RAHNEFELD G. W.
Published: March 2010

Data on 1151 calvings recorded over a 4-yr period at the Agriculture Canada Research Station, Brandon, Manitoba were analyzed to examine the influence of various factors on the time of day of calving of beef cows. Factors examined were year of calving, sex of calf, age of cow, weight of cow, calf birth weight and breed type. The hourly distribution of calvings was relatively uniform over the 24-h period. Slightly more calves were born from 0700 h to 1900 h (51.5%) than between 1900 h and 0700 h. Breed of maternal grandsire and of maternal granddam were the only factors that appeared to influence the time of parturition. Percentages of calves born during the day (0700–1900 h) having Hereford, Charolais, Simmental and Limousin grandsires were 59.0, 54.2, 51.0 and 45.6, respectively, whereas 55.9, 55.6 and 41.0% of the calves from Hereford, Angus and Shorthorn granddams, respectively, were born during the day. The hourly distribution of 212 potentially abnormal calvings was significantly uneven. The highest incidence of abnormal calving occurred from 1100 h to 1500 h (22.2%) and the lowest from 2300 h to 0300 h (12.1%). Key words: Beef cows, parturition, hourly distribution
APPLICATION OF CONTROLLED REPRODUCTION TO SHEEP FLOCKS IN NEWFOUNDLAND
Authors: SHRESTHA J. N. B. , AINSWORTH L. , HEANEY D. P. , SMITH A. N.
Published: March 2010

A 3-yr study demonstrates that commercially acceptable reproductive performance can be achieved in breeding sheep following the application of a fluorogestone-acetate- (FGA-) impregnated intravaginal sponge and pregnant mare's serum gonadotrophin (PMSG) treatment to induce a synchronized estrus under field conditions. Overall fertility, prolificacy and fecundity levels of 76%, 1.92 and 148%, respectively, resulted from breeding at the synchronized estrus, and 94%, 1.86 and 175%, respectively, due to breeding at the synchronized and subsequent estruses in the breeding (fall) season. In the nonbreeding (spring) season, these responses were 51%, 1.73 and 88%, respectively, at the synchronized estrus, and 63%, 1.61 and 109%, respectively, due to breeding at the synchronized and subsequent estruses. Significant farm-to-farm variation was observed with reproductive performance ranging from 77 to 100% for fertility, 1.45 to 2.74 for prolificacy, and 134 to 274% for fecundity in the estrous season. There were no significant differences among farms after synchronization and breeding during the anestrous season. Key words: Sheep, synchronization, fluorogestone acetate, pregnant mare's serum gonadotrophin, season, farm flocks.
COMPARISON AMONG SIRE GROUPS IN CONCEPTION RATE, GESTATION LENGTH AND CALVING EASE OF THEIR MATES
Authors: BATRA T. R. , McALLISTER A. J. , LEE A. J. , ROY G. L. , DARISSE J. P. F. , VESELY J. A. , WINTER K. A.
Published: March 2010

Data on conception rate, gestation length, incidence of calving difficulty and retained placenta were obtained from 269 heifers and 525 cows as mates of the pureline foundation phase sires of the National Cooperative Dairy Cattle Breeding Project. The data were analyzed by least squares separately for heifers and cows using a model containing fixed effects for station, year of calving, season of calving, sex of calf, line, sire groups within line, sires within sire group and line, birth weight of the calf as a covariate and residual. Effect of age at first calving was used as a covariate in the heifer data while the effect of parity was included in the cow data. The effect of station, year of calving, season of calving, line, sire groups within line and sires within sire group and line were significant (P < 0.05) for gestation length of heifers and cows. Other significant (P < 0.05) effects in heifers were age at calving on conception rate, sex and birth weight of the calf on calving difficulty. In addition the effects of sex and birth weight of the calf on gestation length, station and parity on calving difficulty and station and line on retained placenta were significant in cows. Key words: Reproductive performance, dairy cattle
PERFORMANCE OF DAIRY CROSSES WITH THE HEREFORD IN A RANGE ENVIRONMENT
Authors: LAWSON J. E.
Published: March 2010

The performance of Brown-Swiss-, Holstein-, and Hereford-sired calves produced in a specific Hereford cow herd over 2 yr was evaluated in a southern Alberta range environment. Holstein × Hereford heifers exceeded Brown Swiss × Hereford and Hereford heifers in 200-day weight and 365-day weight, and lost less weight during the winter. Crossbred bull calves were heavier than Herefords in initial feedlot weight and 365-day weight, and had heavier and longer carcasses at the same age. Although the crossbreds consumed about 15% more digestible energy (DE) than the Herefords during the 168-day feedlot period, the three groups did not differ in megajoules (Mj) of dietary energy per kilogram of gain. Holstein × Hereford bulls had the highest feedlot average daily gain and the least fat cover over the longissimus dorsi. Brown Swiss × Hereford bulls had more lean, less marbling, and the highest cutability percent. An important aspect of the study was the demonstrated hardiness of the crossbred heifers derived from the apparently well-adapted Hereford cow herd in the tough range environment. Key words: Beef crosses, beef cattle performance, crossbreeding
THE ACCURACY OF TWO RECORDING INSTRUMENTS IN THE MEASUREMENT OF SUBCUTANEOUS FAT THICKNESS IN PORK CARCASSES
Authors: JONES S. D. M. , ALLEN O. B. , HAWORTH C. R.
Published: March 2010

The Hennessy and Chong Fat Depth Indicator (FDI) and a compact, ultrasonic instrument (Renco) were compared using 152 pork carcasses. Fat thickness measurements were taken 5 cm off the midline at five locations (shoulder, SF; mid-back, MB; last rib, LR; loin, LO; and lumbar, LU) on both sides of the carcass immediately after sticking (before scalding), after splitting the carcass and 24 h postslaughter (FDI only). Actual thicknesses were determined, using a ruler, for these locations on the left side and at the midline of the split carcass. Instrument readings made on the right or left side of the carcass were not different (P > 0.05). Precision (similarity of first and repeated reading of fat thickness) was higher for the FDI than the Renco with average residual standard deviations for both instruments being 1.2 mm and 1.4 mm, respectively. Precision was similar for all locations except the SF site which had significantly (P < 0.05) poorer values. The average bias was smaller for the FDI than for Renco, but was not large for either instrument except at the shoulder. However, regressions of instrument readings on ruler measurements for both instruments gave slopes that were considerably lower (P < 0.05) than unity with positive values for intercepts. This indicates that fat thickness would be over- and under predicted in lean and fat carcasses, respectively, using both instruments. Key words: Swine, carcass backfat, ultrasonic, fat probes
GLUCOSE CONSUMPTION AND LACTIC ACID PRODUCTION BY ERYTHROCYTES FROM DOUBLE-MUSCLED CATTLE
Authors: BASARAB J. A. , BERG R. T. , THOMPSON J. R.
Published: March 2010

The in vitro glucose consumption and lactic acid production by erythrocytes from 20 cattle of a Beef Synthetic (SY) breed group and 25 cattle of a double-muscled (DM) breed group were determined. There were three age groups and two sexes within each breed group. Animals within the DM breed group were categorized as either phenotypically normal- to moderate-muscled (DM carriers) or extreme-muscled (extreme DM) based on the phenotypic expression of the double-muscling trait and on their breeding history. Both DM phenotypes had higher (P < 0.01) erythrocyte glucose consumption and lactic acid production than normal-muscled, noncarrier cattle of the SY breed group. Extreme DM cattle were not different (P > 0.05) in either their erythrocyte glucose consumption or lactic acid production compared with DM carriers. No difference (P > 0.05) due to breed or phenotype was observed in the molar ratio of lactic acid produced to glucose consumed by erythrocytes. These results suggest that carriers of the Double Muscled Syndrome, regardless of phenotypic expression of the double-muscling trait, have a higher rate of erythrocyte glycolysis than normal cattle. Key words: Cattle, double muscled, erythrocyte, glucose, lactic acid
SERUM PROGESTERONE AND INITIATION OF OVARIAN ACTIVITY IN PREPUBERAL HEIFERS TREATED WITH PROGESTERONE
Authors: RAJAMAHENDRAN R. , LAGUË P. C. , BAKER R. D.
Published: March 2010

The influence of progesterone on the initiation of ovarian activity in 32 prepuberal Holstein heifers (250 kg) was studied by inserting subcutaneous single or double Silastic implants (60-cm2 silicone rubber tubing containing 1 g progesterone or 120-cm2 tubing with 2 g progesterone) or Silastic intravaginal devices (SID) (120-cm2 tubing with 2 g progesterone) or a progesterone-releasing intravaginal device (PRID) (210-cm2 coil with 2 g progesterone). Blood samples were collected every 6 h on days −1, 4, 8, 12, 16 and 20 after insertion. Serum progesterone, quantitated by radioimmunoassay, varied with treatment (P < 0.01), with the day following treatment (P < 0.01) and with the time of day (P < 0.01). The highest concentrations (mean ±SE 2.1 ± 0.06 ng/mL) appeared at 0600 h and the lowest (mean ± SE 1.7 ± 0.08 ng/mL) at 1800 h. Serum progesterone was consistently greater (P < 0.01) in the PRID group. Location (subcutaneous vs. intravaginal) of the 120-cm2 tubing, i.e. double implant or SID, had no influence per se on serum progesterone. Heifers treated with the 60-cm2 tubing, i.e. single implant, had lower (P < 0.01) serum progesterone concentrations than heifers in the other three treatment groups. When the implants and devices were removed on day 20, two females in each of the four treatments received either saline, 5 mg estradiol-17β (E2), 500 IU PMSG, or 100 g GnRH. None of the heifers treated with the single implant ovulated. Of the saline-, E2-, PMSG- and GnRH-treated heifers, 0, 5, 6 and 2 showed estrus and 0, 2, 6 and 2 ovulated, respectively. PMSG-treated females had a mean of 2.5 ovulations. This study further demonstrates that adequate progesterone priming increases the response of prepuberal heifers to an ovulatory hormone stimulation. Key words: Progesterone, ovarian activity, prepuberal heifers, hormonal stimulation, silastic implants
TYROSINE TURNOVER AND OXIDATION IN THE OVINE FETUS IN UTERO
Authors: SCHAEFER A. L. , KRISHNAMURTI C. R.
Published: March 2010

The tyrosine turnover in chronically catheterized ovine fetuses in utero at 120–130 days of gestation was determined from plateau-specific activity following the continuous infusion of L-[U-14C] or L-[2,3,5,6 3H] tyrosine. The irreversible loss of tyrosine in the fetus was determined to be 5.790 mmol∙day−1∙kg−1. Since values based on irreversible loss have been reported to result in an overestimation of fetal utilization of substrates, dual labelling experiments were undertaken in which 3H-tyrosine was infused into the ewe and, 14C-tyrosine into the fetus simultaneously. Under these conditions a two-compartment kinetic model was used to determine net placental transfer, endogenous production, and net utilization of tyrosine by the fetus, which were respectively; 5.153, 1.287 and 6.536 mmol∙day−1∙kg−1. In addition, from the ratio of the plateau-specific activity of blood 14CO2 and, 14C-tyrosine it was estimated that the fraction of net utilization of tyrosine used for oxidation was 5.2%. The use of these kinetic parameters in estimating protein synthesis in the ovine fetus is discussed. Key words: Sheep, fetus, tyrosine, turnover, oxidation
THIAMIN SUPPLEMENTATION OF AN ALL-CONCENTRATE DIET FOR FEEDLOT STEERS
Authors: GRIGAT G. A. , MATHISON G. W.
Published: March 2010

Thirty beef-type steers were fed an all-concentrate barley-based diet supplemented with 1.9 mg thiamin per kilogram of diet or a similar unsupplemented diet. Average daily gains (1.14 kg/day vs. 0.92 kg/day) and carcass weights (281 kg vs. 265 kg) were higher [Formula: see text] for the supplemented group. Supplemental thiamin had no significant effect on other measures of performance or other carcass traits. Of 168 samples collected over 12 sampling periods, 11 samples from nine animals exhibited more than a 15% increase in the activity of the erythrocyte transketolase enzyme (E.C.2.2.1.1) in response to added thiamin pyrophosphate (TPP effect) which suggested that a marginal thiamin deficiency existed in some of these steers. Supplemental thiamin did not significantly reduce the TPP effect, A trend [Formula: see text] for a negative linear relationship was found between 2-wk weight gains of the steers and the TPP effect. A positive relationship [Formula: see text] was found between the TPP effect and glucose concentrations. Plasma urea concentrations were not related to treatment but were low enough (4.52 mg urea N/dL) to suggest that the animals were deficient in dietary protein. Plasma magnesium and calcium concentrations were unrelated to treatment or animal performance, but plasma magnesium concentrations did increase [Formula: see text] in the first half of the trial. The results indicated that some animals were marginally deficient in thiamin and that decreased production in cattle fed all-concentrate diets is possibly due to thiamin inadequacies. Key words: All-concentrate, feedlot steers, thiamin, TPP effect, transketolase
EFFECTS OF TWIN-FOSTER CALF REARING AND OF AGE AT WEANING ON COW AND CALF PERFORMANCE
Authors: ROSECRANS J. G. , NIPPER W. A. , HOHENBOKEN W. D. , WEBER D. W.
Published: March 2010

The effects of twin-foster calf rearing on calf weight at 200, 291 and 365 days postcalving, on calf weight produced per cow, and on reproductive performance of cows were evaluated using fall-born calves. Eleven Holstein × Angus or Holstein × Hereford 2- or 3-yr-old cows rearing 20 Holstein or Limousin crossbred calves were compared with cows of similar age and breeding rearing 13 single-suckled Limousin crossbred calves. Twin calves were significantly lighter than single calves, but calf production per cow at 200 days postcalving was increased 39% by twin fostering. At 291 and 365 days postcalving, production per cow from twin fostering was 50% and 55% greater than that from single-suckled cows whose calves were weaned at 291 days. Twin fostering did not depress reproductive performance of the cows. However, supplemental feed costs and labor required at fostering were considered to restrict applicability of this management practice. Weaning at 9 mo as opposed to 200 days of age increased calf production per single-suckled cow without a substantial increase in costs. Key words: Cow-calf, twin foster, single-suckled, fall calving
THE EFFECT OF CATTLE DIET ON THE METABOLISM OF 3-NITROPROPANOL BY RUMINAL MICROORGANISMS
Authors: MAJAK W. , CHENG K.-J. , HALL J. W.
Published: March 2010

Rumen fluid was obtained over a 2-yr period (1980–1981) from cattle on various diets, to determine the effect of diet on microbial metabolism of 3-nitropropanol (NPOH), the toxic metabolite that occurs in certain species of the legume family. In both years, NPOH was degraded most rapidly (P < 0.05) when range diets contained Kentucky bluegrass (Poa pratensis). Pinegrass (Calamagrostis rubescens) range was associated with high rates of NPOH degradation (< 200 μmol∙L−1∙h−1) in 1980 but not in 1981. Feedlot (alfalfa hay and grain, alfalfa hay, and corn silage), pasture (orchardgrass and alfalfa) and bluebunch wheatgrass range (Agropyron spicatum) diets showed lower rates of NPOH metabolism, but a new stand of orchardgrass (pasture) yielded high rates of NPOH metabolism in 1981. Rapid rates of nitrite reduction were correlated with the degradation of NPOH, suggesting rumen bacteria that detoxify nitrite and NPOH may be similar. The induction of NPOH metabolism by dietary components is considered and ruminal rates of NPOH metabolism are discussed in relation to forage quality. Preliminary results indicate that nitrate may serve as a substrate for inducing ruminal detoxification of nitrite and NPOH in cattle. Key words: Detoxification, rumen microorganisms, 3-nitropropanol, miserotoxin, cattle nitrite
UTILIZATION OF PROTEIN FROM PEAS, BARLEY, BUTTERMILK POWDER AND SOYBEAN MEAL BY EARLY-WEANED PIGS
Authors: CHRISTISON G. I. , SOLANO N. M. PARRA DE
Published: March 2010

Six pairs of newly weaned 21-day-old pigs were assigned to each of four diets where 80% of the dietary protein originated from soybean meal (SBM), buttermilk powder, barley protein concentrate or pea protein concentrate (PPC). The remainder of the protein came from naked oats. From 21 to 42 days of age, daily gains on the SBM (327 g) and buttermilk powder diets (355 g) did not differ, but were lower (P < 0.05) on the barley protein concentrate (259 g) and PPC (171 g) diets. Daily feed intake was less (P < 0.05) for the PPC diet (262 g) than for the SBM, buttermilk powder or barley protein concentrate diets (448, 445 and 368 g, respectively). Apparent digestibility of dietary crude protein increased by 5–10 percentage points from 28 to 41 days of age. On the basis of the known protein digestibility of the naked oats, and using the mean protein digestibility value of each diet, the protein digestibility of each protein source was calculated to be: SBM, 76%; buttermilk powder 86%; barley protein concentrate, 86%; and PPC, 69%. In a second experiment, diets were formulated so that PPC supplied 0, 27, 53 or 80% of the dietary protein. There was a general decline in growth rate and in feed intake as pea protein increased, with a marked decrease in growth rate at the final PPC increment. It is suggested that PPC should not contribute more than 27% of the dietary protein (10% of the diet) for weanling pigs. Key words: Weanling pigs, pea protein, buttermilk powder, barley protein, soybean meal, digestibility
LIVE ANIMAL EVALUATION OF TWO ULTRASONIC PROBES AS ESTIMATORS OF SUBCUTANEOUS BACKFAT AND CARCASS COMPOSITION IN PIGS
Authors: SATHER A. P. , FREDEEN H. T. , MARTIN A. H.
Published: March 2010

Ultrasonic probe data recorded on a total of 186 Lacombe barrows and gilts were obtained by two operators using the Krautkramer USM2 and Scanoprobe 731A. Backfat measurements were taken, prior to marketing, at approximately 90 kg at locations 5 cm off either side of the midline on the mid-back and on the loin, corresponding to Canadian Swine ROP policy. These measurements were then repeated on the carcass. Correlations between average probe backfat (PF) and average probe site carcass fat (CF) were similar for both operators using the USM2 (r = 0.78, 0.84) and the 731A (r = 0.78, 0.82). The two units accounted for similar proportions of the variances of percent carcass lean (R2 = 0.35, 0.35) and of percent carcass fat (R2 = 0.45, 0.47). Consideration of the effects of sex and weight increased the R2 value by 2–6% for percent carcass lean and 6–7% for percent carcass fat. The USM2 (PF = 19.2, 20.4 mm) produced results in closer agreement with CF (20.0 mm) than did the 731A (PF = 18.9, 19.4 mm), for each operator. However, greater bias appeared to be associated with the USM2 than with the 731A, for measuring PF as an estimator of CF. Overall, it was judged that both machines were equivalent in their ability to measure subcutaneous backfat and to predict carcass composition from the live animal. Considering the additional cost of the USM2, purchase of this machine could not be justified on the basis of performance. Key words: Swine, ultrasonic probes, backfat, live animal evaluation, carcass evaluation
EFFECT OF DOUBLE FORCE FEEDING ON TRUE METABOLIZABLE ENERGY
Authors: SCHANG M. J. , LEESON S. , SUMMERS J. D.
Published: March 2010

Four feedingstuffs were assayed for true metabolizable energy (TME) using a conventional single feeding or two feedings followed by a reduced fecal collection time. There was no significant (P < 0.05) difference in the TME values for any of the ingredients due to feeding technique. It is suggested that double force feeding could provide an alternative approach to TME results, allowing birds to increase the amount of feed in their gut, when compared to the amount of feed provided for the conventional assay. Key words: energy, feed intake, rate of passage
THE EFFECTIVENESS OF ADDING PENICILLIN TO A MIXTURE OF CHLORTETRACYCLINE AND SULFAMETHAZINE TO IMPROVE GROWTH OF WEANLING PIGS
Authors: BRIDGE R. , OWEN B. D. , BEAMES R. M.
Published: March 2010

Three groups, each of five pigs, of initial age 5–6 weeks and initial weight 12 kg, were placed on each of three wheat-soybean-meal-based diets of 18% crude protein content. The diets contained either (a) no antibiotic, (b) 110 mg/kg chlortetracycline hydrochloride, 110 mg/kg sulfamethazine and 55 mg/kg penicillin, or (c) diet (b) minus penicillin. Both antibiotic treatments produced a similar growth response of approximately 12%, which resulted partly from an increased feed intake and partly from an improved efficiency of feed utilization. Key words: Antibiotic, pigs, growth
DUODENAL FLOW AND SOLUBLE PROPORTIONS OF ZINC, MANGANESE, COPPER AND IRON IN THE RUMEN FLUID AND DUODENAL DIGESTA OF FAUNATED AND DEFAUNATED SHEEP
Authors: IVAN M. , VEIRA D. M.
Published: March 2010

Measurements of soluble proportions in the rumen fluid and duodenal digesta and flow into the small intestine of zinc, manganese, copper and iron were carried out in defaunated and faunated sheep. There was no significant (P > 0.05) effect of the defaunation on any measurements. It was concluded that ciliate protozoa do not have a critical role in trace metal metabolism in the rumen of sheep. Key words: Defaunation, sheep, trace elements, solubility
RELATIONSHIPS OF SCROTAL CIRCUMFERENCE WITH BODY WEIGHT AND BACKFAT THICKNESS IN MULTIBREED SYNTHETIC POPULATIONS OF YOUNG BEEF BULLS
Authors: SHARMA A. K. , BERG R. T.
Published: March 2010

Relationships of scrotal circumference (SC) with body weight (BW) and backfat thickness (FT) as measured from scanograms were studied. A total of 935 observations on growing multibreed synthetic beef bulls on a postweaning performance test were available from a commercial herd for this study. Significant breed group, period and group × period interaction effects were noted on SC, BW and FT. BW and SC increased significantly during the test in all breed groups, while FT showed no change in three breed groups. Repeatability pooled across groups for SC was estimated as 0.72; 0.66 after adjusting for BW. Significant correlations were noticed between SC and BW within each breed group. Partial correlations between SC and BW at constant FT were not different from gross correlations. Linear regression coefficients of SC on BW were significant in all groups and showed heterogeneity among groups but not between periods within groups. Adjustments of SC for BW should, therefore, be breed group specific. BW alone accounted for considerable variation in SC, from 38 to 76%. Simple correlation coefficients between SC and FT were low and significant in only two groups. A significant but low positive relationship was noted between SC and FT at constant BW in a group fed a high-concentrate diet during the postweaning gain period, but there was no relationship in four other groups. Results indicated that the method of adjusting SC for FT as an indirect way of adjusting for scrotal fat was not satisfactory. Key words: Bulls, scrotal circumference, growth