bluuebunny/crossref_metadata_2025 huggingface dataset:
ENERGY COST OF PREGNANCY IN SINGLE- AND TWIN-BEARING EWES
Authors: LODGE G. A. , HEANEY D. P.
Published: March 2010

Forty mature ewes were paired on the basis of weight; one ewe of each pair was bred (P) while the other was allotted to the nonpregnant (NP) group. Feed allowance, on the basis of initial weight, was the same within pairs. At day 140 of pregnancy, each P ewe and her respective NP pairmate were slaughtered for chemical analyses of body components and calculation of energy values. Among the 19 pairs of ewes completing the experiment, P ewes had significantly (P < 0.001) lighter carcass, skin and viscera, and fleece than NP ewes; significantly heavier liver, mammary gland, uterus (P < 0.001), and blood (P < 0.05); only weights of head and feet were not significantly different. Percentages of fat were significantly less in carcass, skin and viscera, and mammary gland (P < 0.001) in P than NP ewes; significantly greater in liver (P < 0.001); not significantly different in fleece or uterus. Percentages of protein were significantly less in liver, blood, and uterus (P < 0.001) in P than in NP ewes; significantly higher in skin and viscera (P < 0.05) and mammary gland (P < 0.001); not significantly different in carcass or fleece. Weights of fat were significantly less in carcass, skin and viscera (P < 0.001), and fleece (P < 0.01) of P than of NP ewes; significantly greater in liver, mammary gland, and uterus (P < 0.001). Weights of protein were significantly less in carcass (P < 0.001), skin and viscera (P < 0.05), and fleece (P < 0.001) of P than of NP ewes; significantly greater in liver, mammary gland, and uterus (P < 0.001). Energy value of maternal tissues of P ewes was 40.1 Mcal less than total energy value of the P ewes (P < 0.001), of which 9.3 Mcal was accountable in growth of concepta. Average heat increment of gestation was therefore 30.7 Mcal, comprising 18.1 Mcal in single-bearing ewes (S) and 40.5 in those bearing twins (T). Net efficiency of energy utilization for gestation was 24.5% in S ewes and 17.5% in T ewes; respective gross efficiencies, including the maternal maintenance requirements, were 2.7 and 3.4%.
ORGANIC ACID TREATMENT OF HAY
Authors: CANDLISH E. , CLARK K. W. , INGALLS J. R.
Published: March 2010

Orchard grass, alsike clover, and an alfalfa–brome mixture were field treated before baling with either formic acid, acetic acid, propionic acid, ChemStor, or HaySavor at levels between 0.05–0.11% on a fresh weight basis. The temperature of the untreated orchard grass hay was 137 F (58 C) and mold was visible after 3 days; formic acid-treated orchard grass hay was 102 F (39 C) and showed traces of mold; no mold was visible in the ChemStor-treated orchard grass bales and temperature was 91 F (33 C). Acetic acid treatment seemed to encourage mold growth in alsike clover hay over 30% moisture at the time of baling. Dry matter (DM) intake by sheep was significantly higher (P < 0.05) for the untreated hay compared with the propionic acid-treated alfalfa–brome hay. The lowest intake was with the formic acid-treated hay. Acid treatment did not significantly affect (P > 0.05) the DM digestibility of the alfalfa–brome hay, although the untreated hay had a higher DM digestibility than the acid-treated hay in the same treatment square.
FATE OF 75Se-SELENOMETHIONINE IN THE GASTROINTESTINAL TRACT OF SHEEP
Authors: HIDIROGLOU M. , JENKINS K. J.
Published: March 2010

A total of 30 wethers was used to study the movement of 75Se-selenomethionine in tissues and contents of various sections of the digestive tract after a single oral or intravenous dose of the selenocompound. After intravenous administration, 75Se-selenomethionine was detected in the upper part of the small intestine lumen after 3–5 h and to a lesser extent in the abomasum contents at 24 h. The highest specific activity (cpm/g of fresh tissue) in gastrointestinal tract tissue was found in the upper jejunum at 3 h postdosing. When the labeled selenocompound was given orally, the midjejunum tissue had the highest 75Se specific activity at 24 h. Supernatant and sediment fractions of gastrointestinal tract contents resulting from centrifugation at 30,000 × g were treated with 20% trichloroacetic acid. For both modes of administration, the trichloroacetic acid-soluble portion of the various gastrointestinal tract contents had higher 75Se activity in the supernatant than in the sediment. Up to 24 h, the acid-soluble part of the two centrifugal fractions was much higher for the upper part of the small intestine than for the fore-stomach contents.
SUPPLEMENTAL DIETARY COPPER AND THE DESATURATION OF 1-14C-STEAROYL-COENZYME A BY PORCINE HEPATIC AND ADIPOSE MICROSOMES
Authors: HO S. K. , ELLIOT J. I.
Published: March 2010

Optimal assay conditions for porcine hepatic and adipose stearoyl-CoA desaturase systems were established. In each of the two experiments conducted, pigs were allotted to four groups in a 2 × 2 factorial design involving two diets (basal or basal plus 250 ppm supplemental copper) and two sexes (barrows and gilts). In experiment 1 (16 pigs), copper supplementation of the swine diet resulted in a slight but nonsignificant increase in the ability of hepatic microsomes to desaturate 1-14C-stearoyl-CoA. With an increased number of animals (24 pigs) in experiment 2, significant increases in stearoyl-CoA desaturase activity were observed in the hepatic (P < 0.05) and adipose (P < 0.01) microsomes of copper-supplemented pigs. No sex differences nor copper × sex interactions in the activities of the stearoyl-CoA desaturase systems were found. It is suggested that supplemental dietary copper enhances the specific activities of both hepatic and adipose stearoyl-CoA desaturase systems, and that this enhancement contributes to the observed decrease in stearate and increase in oleate content of depot fat.
COMPARISON OF INTACT, LATE-CASTRATED, AND DIETHYLSTILBESTROL (DES)-IMPLANTED BOARS WITH BARROWS AND GILTS: NITROGEN AND ENERGY DIGESTIBILITY, NITROGEN RETENTION, CARCASS MEASUREMENTS, MUSCLE ANALYSES, AND RESIDUAL DES IN MUSCLE TISSUE
Authors: NEWELL J. A. , BOWLAND J. P.
Published: March 2010

Forty boars, eight barrows, and eight gilts were allotted in groups of four pigs each at an average weight of 13.1 kg. Metabolism studies with a portion of the animals were conducted at 15 and 50 kg liveweight. Although no statistical differences between sexes were found in these studies, barrows tended to digest more nitrogen (N) but to retain less than boars and gilts. N digestibility (DN) and retention (NR) values at 50 kg were higher than those at 15 kg. The three sexes were found to be similar in energy digestibility (DE) and metabolizable energy (ME). Significant differences were found for boars in DE and ME coefficients between the two periods, averaging 83.2 and 85.6% DE in the 15- and 50-kg periods, respectively. At 70 kg, 16 boars were implanted with 96 mg of diethylstilbestrol (DES), 16 boars were castrated, and 8 boars were left intact. Barrows had thicker backfat (P < 0.05) and lower (P < 0.05) grade index than any of the other treatments. Late-castrated boars showed a general trend to revert to the carcass characteristics of barrows but were still superior to barrows at market weight. No significant differences between treatments were found for dry matter, protein, fat, or ash content of the longissimus muscle. No residual DES was found in the muscle tissue of the implanted boars.
1971 USE AND BEEF POTENTIAL OF CALVES FROM ONTARIO DAIRY HERDS
Authors: CORE J. E. , STONE J. B. , BURGESS T. D. , WRIGHT P. A.
Published: March 2010

A mail survey of a sample (924) of Ontario dairy farmers was conducted to gather information on the use of dairy bull calves born on their farms. It was found that there are 201,700 dairy bull calves available for meat production in Ontario, based on the data obtained in this study. It was found that 89,800 of these calves were reared on the home farm for meat purposes, and 111,900 were sold as bob calves. It was also estimated that 115,700 crossbred dairy–beef calves were available for meat purposes. Overall, a total of 346,500 calves could be used for meat. This includes bull calves, extra heifer calves, and crossbred calves.
PREPARATION OF HIGHLY PURIFIED 3-BUTENYL- AND 2-HYDROXY-3-BUTENYLGLUCOSINOLATES
Authors: WETTER L. R. , DYCK J.
Published: March 2010

not available
EFFECTS OF POSTFEEDING INTERVAL ON BLOOD CONSTITUENTS RELATED TO ENERGY METABOLISM IN NONPREGNANT ANGUS AND HEREFORD HEIFERS
Authors: BOWDEN D. M.
Published: March 2010

Ten Angus heifers and 10 Hereford heifers were fasted for 48 h to study changes in blood glucose, plasma nonesterified fatty acids (NEFA), and plasma ketone concentrations and their relationships to prefast feeding levels and breed. Prior to fasting, five heifers of each breed were fed for 140 days on one of two rations, which produced significantly different average rates of gain (0.16 vs. 0.47 kg/day) and average depths of subcutaneous adipose tissue (5.0 vs. 10.3 mm). Blood was sampled at 1, 24, and 48 h postfeeding. Blood glucose concentrations were higher (P < 0.01) at 24 h postfeeding but did not change from 24 to 48 h postfeeding. Plasma NEFA concentrations increased during the 48-h fast. Plasma ketones were lower (P < 0.01) at 24 h postfeeding but at 48 h were higher (P < 0.01) than at 1 h postfeeding. Packed cell volume (PCV) increased during 24 and 48 h of fasting. Blood concentrations of glucose, NEFA, and ketones at either 24 or 48 h of fasting were not influenced by prefast feeding level. Angus heifers had higher (P < 0.05) blood glucose and higher (P < 0.05) PCV than Hereford heifers. Correlations between the blood constituents at the three sampling times were generally low. Only the correlations of plasma NEFA with ketone concentrations at 24 h postfeeding (.55) and glucose with PCV at the initial sampling (−.52) reached significance (P < 0.05).
SERUM ESTERASE ACTIVITY OF YORKSHIRE GILTS AT PUBERTY
Authors: FRIEND D. W. , GRUNDER A. A.
Published: March 2010

not available
EFFECTS OF PELLETING, ROUGHAGE LEVEL, AND HORMONE IMPLANTATION ON THE UTILIZATION OF FINELY GROUND CRESTED WHEATGRASS BY GROWING LAMBS
Authors: BEACOM S. E. , THORLACIUS S. O. , TROELSEN J. E.
Published: March 2010

Rations containing 50, 70, and 90% crested wheatgrass and one in which the level of crested wheatgrass was gradually reduced from 90 to 50% were fed in the ground (0.48-cm screen) and pelleted forms to wether and ewe lambs, with and without Synovex implants, in a factorially designed experiment. Pelleting increased dry matter (DM) intake, rate of gain, and feed efficiency by 15, 47, and 23%, respectively (P < 0.05). The level of roughage in the ration did not significantly affect dry matter intake, rate of gain, or feed efficiency, and there was no significant interaction between ration form and roughage level. In vitro digestible energy content of the ground rations was 2.66, 2.46, and 2.44 kcal/g DM at the 50, 70, and 90% roughage levels, respectively; the corresponding values for the pelleted rations were 2.75, 2.51, and 2.49 kcal/g DM. The implant treatment increased rate of gain and feed efficiency by 18 and 17%, respectively (P < 0.05) and this effect was not influenced by ration form, level of roughage, or sex of lamb. Dressing percentage was greater and loin area smaller (P < 0.05) at the 50% roughage level than at the 90% level. Pelleting decreased loin area of females (P < 0.05) but not of males. Dressing percentage and backfat thickness tended to be increased by pelleting but this was not significant. Synovex implants decreased dressing percentage (P < 0.05) but did not significantly affect backfat thickness or loin area.
RAW AND AUTOCLAVED FABA BEANS IN CHICK DIETS
Authors: MARQUARDT R. R. , CAMPBELL L. D.
Published: March 2010

Two experiments were conducted with male Leghorn chicks over 20- and 21-day periods to study the influence of heat treatment (autoclaved 15 min at 121 C) on the antinutritional factor(s) of the faba bean (Vicia faba L. var. minor). Pancreas size decreased and efficiency of feed utilization was improved in chicks fed diets containing heated as compared with raw faba beans (P < 0.01). The most pronounced effect of heat treatment occurred in diets of high (85%) faba bean content. The decreases in pancreas size and feed:gain ratio were 25 and 12%, respectively. Heat treatment resulted in a significant (P < 0.01) growth response (7.3%) in chicks fed the diet containing 85% faba beans. Weight gain in chicks, however, was not significantly (P > 0.05) affected with diets containing 57 or 28% faba beans and was the same as for chicks fed the 85% heated faba bean diet. The results of the second experiment showed that most of the antinutritional factor(s) in faba beans is associated with the hulless portion of the faba bean. It was also shown that the weight of the hull was approximately 13% of that of the whole bean and that it had a high (45%) content of crude fiber and a low (6%) content of crude protein.
HETEROSIS, BREED-OF-SIRE AND BREED-OF-DAM EFFECTS ON GROWTH RATES OF LAMBS REARED ARTIFICIALLY OR WITH THEIR DAMS
Authors: PETERS H. F. , HEANEY D. P.
Published: March 2010

Heterosis, breed-of-sire and breed-of-dam effects on growth rates were estimated in a 3-yr study of the Suffolk (SU) and Shropshire (SH) breeds of sheep and their reciprocal crosses, utilizing 175 lambs reared artificially with liquid plus solid diet from 2 to 70 days and 225 lambs creep-fed a solid diet and reared with their dams to 70 days. These comprised 135 SU, 76 SH, 82 SU (sire) × SH (dam) and 107 SH × SU lambs reared to 140 days of age. Lambs by SU sires surpassed those by SH sires in growth rate from birth to 70 days (P < 0.01) and from 70 to 140 days (P < 0.05) in artificial rearing, but only from 70 to 140 days (P < 0.01) when reared by their dams. Breed of dam had no significant effect on growth rate of lambs in artificial rearing, but the lambs from SU dams surpassed those from SH dams in growth rate from birth to 70 days (P < 0.01) and from 70 to 140 days (P < 0.05) when the lambs were reared with their dams. Heterosis, as expressed by superiority of crossbreds over purebreds, was significant (P < 0.05) in growth rate from birth to 70 days and from 70 to 140 days for lambs reared artificially, but only in the latter period for lambs reared with their dams.
FOLLICULAR AND LUTEAL CHANGES DURING EARLY PREGNANCY IN THREE BREEDS OF SWINE
Authors: DUFOUR J. J. , FAHMY M. H.
Published: March 2010

Follicular and luteal changes during the first half of pregnancy were studied using 47 Yorkshire (Y), 52 Landrace (Ld) and 44 Lacombe (Lc) sows examined at 23, 42 and 63 days of pregnancy. Follicular fluid weight was greater in Lc than in Y (20%) and Ld (8%) sows. The mean follicular weight for all breeds increased by 22.6% (P < 0.05) from day 23 to day 42 of pregnancy. Yorkshire sows had significantly more small (1–2 mm) follicles than Lc and Ld sows. The average number of small follicles for all breeds was 117 at day 23 and remained unchanged at day 42, but was 20.5% higher (P < 0.01) at day 63. The number of medium (3–5 mm) follicles was similar in the three breeds, whereas that of large follicles (6–10 mm) was greater in Lc than in Y and Ld sows. The number of medium and large follicles increased with the advance in pregnancy. The ovulation rate as measured by the number of corpora lutea was 15.1 in Ld and 14.1 in Y and Lc. Luteal tissue weight was less in Y than in Ld and Lc sows. The weight of luteal tissue increased with advancing pregnancy.
PREVENTION OF NUTRITIONAL MUSCULAR DYSTROPHY IN CALVES AND LAMBS BY SELENIUM AND VITAMIN E ADDITIONS TO THE MATERNAL MINERAL SUPPLEMENT
Authors: JENKINS K. J. , HIDIROGLOU M. , PROULX J. E. , WAUTHY J. M.
Published: March 2010

Nutritional muscular dystrophy (NMD) was prevented in suckling beef calves and lambs by the inclusion of selenium (14.8 ppm) and vitamin E (2,700 IU/kg) in the mineral supplement of their selenium-deficient dams. The fortified mineral supplement was provided for the latter two-thirds of gestation and for the 1st mo of lactation. Three to four mo after withdrawal of selenium supplementation, selenium levels in the cow and ewe milk, and in the kidney, liver, muscle and blood of the calves, ewes and lambs were comparable to published values for selenium-deficient animals. During the selenium supplementation period, the blood and milk selenium concentrations of the cows and ewes, and blood selenium levels of their offspring were well within normal ranges for animals raised in Canada and other countries. Thus, the method was effective against dystrophy and there was no evidence that it resulted in any abnormal selenium residues. The use of selenium plus vitamin E in mineral supplements is an economical, convenient and practical method for preventing NMD in ruminants. Its general use in Canada on a veterinary prescription basis, as required, appears indicated, pending clearance for the addition of selenium to ruminant supplements and rations.
FABA BEAN AS A SUBSTITUTE FOR SOYBEAN MEAL OR RAPESEED MEAL IN RATIONS FOR LACTATING COWS
Authors: INGALLS J. R. , McKIRDY J. A.
Published: March 2010

not available
USE OF HCl INSOLUBLE ASH AS AN INDEX MATERIAL FOR DETERMINING APPARENT DIGESTIBILITY WITH PIGS
Authors: McCARTHY J. F. , AHERNE F. X. , OKAI D. B.
Published: March 2010

not available
CHANGES IN ESTIMATES OF SILAGE DRY MATTER INTAKE OR APPARENT DIGESTIBILITY AS AFFECTED BY METHODS OF DM DETERMINATION
Authors: JONES G. M. , LARSEN R. E.
Published: March 2010

Apparent digestibility coefficients and voluntary dry matter (DM) intakes by sheep fed 11 silages, comprising 3 corn, 4 legume-grass and 4 corn-hay crop silage mixtures, were estimated when silage DM content was determined by (1) toluene distillation (TD), corrected for volatiles lost into the aqueous distillate, (2) uncorrected TD, (3) freeze-drying (FD), (4) oven-drying (OD) at 40 C and (5) OD at 65 C. Highest nutrient digestibility and DM intake (P < 0.05) data were obtained by the method of corrected TD. DM intake and DM digestibility were underestimated by 7.4 and 12.0%, respectively, when oven-drying at 65 C was compared to corrected TD (P < 0.01). Digestibility coefficients and DM intakes were similar between FD and OD at 40 C. These results suggest that in vivo expressions of silage nutritive value should be based upon corrected TD for silage DM content and that biochemical determinations can be conducted on silage that has been oven-dried at 40 C.
EFFECTS OF TREATING RAPESEED MEAL AND CASEIN WITH FORMALDEHYDE ON APPARENT DIGESTIBILITY AND AMINO ACID COMPOSITION OF RUMEN DIGESTA AND BACTERIA
Authors: SHARMA H. R. , INGALLS J. R.
Published: March 2010

Four rumen-fistulated young Holstein steers (189 kg average weight) were used in a latin square design. The steers were fed four semipurified pelleted diets, containing either 19% rapeseed meal (RSM) or 7.5% casein protein untreated or formaldehyde (FA)-treated (0.7 g FA/100 g protein), at frequent intervals. FA treatment of RSM or casein tended to reduce the ammonia production in the rumen of steers receiving the experimental diets and showed little effect on apparent digestibilities of dry matter (DM), crude protein (CP) or nitrogen (N) retention. FA treatment of casein but not of RSM increased (P < 0.05) the flow of total N, non-ammonia N (NAN) and digesta from the rumen. The bacterial N in the rumen digesta varied from 40–61% of the dietary N for the steers fed the experimental diets. FA treatment significantly increased total amino acid concentrations (P < 0.01) in the rumen digesta of steers fed the FA-casein diet and resulted in a nonsignificant (P > 0.05) increase for FA-RSM steers compared with those given untreated diets. Treatment of casein with FA reduced the catabolism of essential amino acids which resulted in larger quantities of these amino acids being transported out of the rumen as compared to the untreated casein diet. However, FA treatment of RSM protein did not promote a significant increase in the quantities of amino acids leaving the rumen of steers receiving the FA-RSM diet compared with those on the RSM diet.
THE EFFECTS OF STAGE OF PREGNANCY, MATING AT THE FIRST AND SECOND ESTRUS AFTER WEANING AND LEVEL OF FEEDING ON FETAL SURVIVAL IN SOWS
Authors: DYCK G. W.
Published: March 2010

Three experiments were conducted to study the effect of the stage of pregnancy, mating at the first and second estrus after weaning and level of feeding on the number of fetuses and fetal survival in 125 Yorkshire and 111 Lacombe primiparous sows. In experiment 1 the sows were fed 1.36 kg of a sow ration twice daily, bred after 18 days postweaning and killed at 10, 25, 67 and 109 days of pregnancy. Sows in experiments 2 and 3 were fed 1.82 and 2.72 kg once daily and bred at the first and second estrus after weaning. In experiment 2 the sows were killed at either 10, 25, 67 or 109 days of pregnancy. In experiment 3 the sows were killed at 67 days of pregnancy. The mean number of fetuses and fetal survival percentages at the four stages of pregnancy using data from both experiments 1 and 2 were 13.1, 88.2%; 12.2, 82.6%; 10.9, 72.9%; and 11.0, 71.9%, respectively. Sows bred at the second estrus had more (P < 0.01) fetuses than sows bred at the first estrus. The increase in fetal numbers was due to an increase in both ovulation rate and fetal survival at the second estrus. The level of feeding had no direct effect on the fetal numbers, ovulation rate or fetal survival. There was an interaction (P < 0.05) between the estrus of mating and level of feeding. Sows fed 2.72 kg per day had fewer fetuses when bred at the first estrus than at the second estrus, whereas sows fed 1.82 kg per day had a similar number of fetuses when mated at the first and second estrus after weaning.
METABOLISM OF SELENOMETHIONINE IN THE RUMEN
Authors: JENKINS K. J. , HIDIROGLOU M. , KNIPFEL J. E.
Published: March 2010

Five rumen-fistulated wethers were dosed intraruminally with a single dose of 75Se-selenomethionine, and the rumen liquor was collected after various time intervals and separated into bacterial, cell-free, and protozoa plus plant material fractions. Maximum 75Se activity in rumen fluid was observed 2 h after labelled selenomethionine was administered. At 6 h post-dosing, 50% of the rumen liquor label was in the bacterial fraction, decreasing to 20% at 96 h. The majority of bacterial 75Se activity was found to be protein-bound. In a second experiment, five wethers were given 75Se-selenomethionine intraruminally, and 2 h later ruminal bacteria were isolated for identification of selenocompounds in the bacterial protein. Paper chromatographic separation of protein enzymatic hydrolysate showed the presence of selenocystine, selenomethionine, elemental selenium, and 40–50% 75Se activity as unidentifiable components. In an in vitro study, 75Se-selenomethionine was incubated with a rumen bacterial fraction, and ion-exchange and paper chromatography were used to identify selenocompounds formed. The results indicated that 75Se-selenomethionine was metabolized by the bacteria to 75Se-selenocystine, with both selenoamino acids incorporated into bacterial protein. With ion-exchange chromatography, unless carrier selenomethionine was added, 75Se-selenomethionine was degraded and a high proportion of 75Se activity remained on the column.
FATTY ACID COMPOSITION OF SHOULDER FAT AND PERINEPHRIC FAT FROM PASTURE-FED HORSES
Authors: BOWLAND J. P. , NEWELL J. A.
Published: March 2010

Shoulder and perinephric fat samples were obtained from 14 horses in October after the horses had been on pasture. Average shoulder fat composition (weight % fatty acids) was C14:0, 4.5; 16:0, 29.5; 16:1, 8.4; 17:0, 0.3; 17:1, 0.4; 18:0, 4.3; 18:1, 36.0; 18:2, 6.4; 18:3, 10.1; and 20:1, 0.1. Perinephric fat was similar in composition, but contained 41.7 ± 2.7% saturated fatty acids (C14:0, 16:0, 17:0 and 18:0) compared with 38.6 ± 3.1% saturated fatty acids for shoulder fat. The analyses indicated the unique composition of horse fat which contains very high levels of C18:3 and low levels of C18:0. Horses fed on pasture appear to have body fat composition similar to a monogastric, but modified by the high C18:3 present in forages. If saturation of fatty acids, similar to that occurring in ruminants, takes place in the cecum of the horse, such fatty acids are apparently absorbed in relatively small amounts.
THE DURATION OF THE BREEDING SEASON OF FOUR BREEDS OF SHEEP
Authors: DUFOUR J. J.
Published: March 2010

Three breeds of sheep (Dorset, Leicester, and Suffolk) and a crossbred line from these breeds (DLS) were observed throughout 1 yr to determine their sexual activity by daily exposure of the ewes to vasectomized rams. The DLS and Dorset ewes exhibited their first estrus earlier in the year (P < 0.01) and stopped cycling later than the Leicester and Suffolk ewes (P < 0.01). The duration of the breeding season in the DLS ewes was 20 days (P > 0.05) longer than in the Dorsets and 70 and 115 days (P < 0.01) longer than in the Leicester and Suffolk ewes, respectively. The percentage of Dorset and DLS ewes showing one or more estrous periods increased progressively from June to reach 100% in September for both breeds. The Suffolk and Leicester ewes commenced to cycle in late August and by September almost all ewes had shown an estrous period. The progressive decline in estrous activity became evident first with the Suffolk in January, then with the Dorset and Leicester in February and with the DLS in March. The Dorset, DLS and Leicester ewes had longer estrous cycles than the Suffolk ewes. Within ewes, length of estrous cycles was highly repeatable for all breeds. False estrus and silent estrus occurred in 1.0 and 3.9% of the estrous periods, respectively. Over successive estrous cycles, length of estrous cycles increased significantly.
COMPARISON OF THE EFFECTIVENESS OF MULTIPLICATIVE AND ADDITIVE ADJUSTMENT FACTORS IN PREWEANING AVERAGE DAILY GAIN OF BEEF CATTLE
Authors: SCHAEFFER L. R. , WILTON J. W.
Published: March 2010

Sixteen adjustment procedures were used to correct 16,529 Angus and 47,293 Hereford preweaning average daily gain records from the 1971–1972 Canadian Federal–Provincial Record of Performance (ROP) Program. Two criteria were defined to determine the appropriateness of additive- or multiplicative-type adjustments and to determine the best of 16 adjustment procedures. Included in the comparisons were the currently used multiplicative ROP age-of-dam factors. Tests for interactions of time with age-of-dam by sex-of-calf by environment subclasses indicated a preference for additive-type factors. The best adjustment procedure of those compared for removing age-of-dam effects and interactions of age of dam with sex and environment was the additive simultaneous adjustment for age of dam, sex of calf, and feeding system. Both the scientific and practical implications of this study were considered important.
ESTROGEN-INDUCED LH RELEASE IN PROGESTERONE-TREATED OVARIECTOMIZED EWES
Authors: YUTHASASTRAKOSOL P. , SIMARAKS S. , PALMER W. M. , HOWLAND B. E.
Published: March 2010

Ovariectomized ewes were injected with either 10 or 30 mg of progesterone, administered either intramuscularly (im) or subcutaneously (sc) at 24, 8, 4 h before, or at the same time, as im injections of 1, 2 or 4 mg of estradiol-17β. Determinations of serum luteinizing hormone (LH), estrogen, and progesterone by radioimmunoassay (RIA) were conducted to study the effects of the treatments on LH release, and the time course of estrogen and progesterone serum concentrations following injection. In the first experiment, progesterone failed to block the estrogen-induced LH release in four of six ewes, and in all three ewes of the second experiment. Intramuscular injection of progesterone resulted in higher circulating progesterone concentrations than sc injection and reached peak levels at 2–4 h postinjection. Estrogen reached peak values at 30 min–2 h postinjection. The results showed that progesterone injected at either 4, 8 and 24 h before, or simultaneously with, a pharmacological dosage of estrogen did not consistently block the LH release in ovariectomized ewes.
INFLUENCE OF SEXUAL ACTIVITY ON SERUM LEVELS OF LH AND TESTOSTERONE IN THE RAM
Authors: SANFORD L. M. , PALMER W. M. , HOWLAND B. E.
Published: March 2010

Two experiments were conducted in January to study the influence of various types of sexual activity on serum levels of LH and testosterone (T) in the ram. Serum LH and T were determined by radioimmunoassay, LH values being expressed in terms of ng NIH-LH-S14/ml. In the first experiment, seven Finnish Landrace rams, 11 mo to 3 yr of age, were allowed individually to mate once (day 1) and continuously mount without intromission for 2 min (day 2) an estrual ewe. Jugular blood (6 ml) was collected by venipuncture at 20-min intervals for at least 2 h prior to and following each type of sexual activity. Two hours following mounting activity on day 2, estrual ewes were walked in front of the rams for 5 min. Blood was collected from each ram at 10 and 30 min following this observation period. Several serum peaks (4–8) of LH occurred in all rams over the two sampling periods (9 h). Although a rise in LH followed one or more of the types of sexual stimulation in four of the seven rams, no consistent relationship was noted between sexual stimulation and LH peaks. In a second experiment, serum samples were obtained every 20 min for two separate 24-h periods, 1 wk apart, from two 3-yr-old Finnish Landrace rams. During the first 24-h period, the rams were penned individually; during the second period each was penned with an estrual ewe. Numerous matings (44 and 24) were recorded for the rams during the latter period, 74% of which took place during the first 12 h. The serum profiles of LH and T during the first 24-h period were characterized by periodic peaks of LH associated with similar changes in T. These profiles appeared to be influenced markedly by sexual activity during the second 24-h period. Higher baseline and mean serum levels of both hormones and a greater number of serum peaks of LH and T were observed during the first 12 h. The serum levels of both hormones then decreased sharply at 13–14 h and remained low for 8–10 h, even though mating occurred periodically during this time. Subsequently, a further serum peak of LH and T was observed before the end of the sampling period.
EFFECTS OF SEVERE WINTER CONDITIONS ON PERFORMANCE OF FEEDLOT STEERS
Authors: MILLIGAN J. D. , CHRISTISON G. I.
Published: March 2010

An analysis of 7 yr of monthly records on a total of 1,970 steers from the University of Saskatchewan feedlot at Saskatoon was conducted to determine the effects of climate on steer performance. During the months of December, January and February (mean monthly temperature −17 C), average daily gain fell to 70% of the average recorded over the remainder of the year. Production efficiency was also severely affected. The feed required per unit of gain and the metabolizable energy intake per unit of gain during winter were, respectively, 149 and 140% of the mean requirements from March to November. These effects were not caused by differences in weight, maturity or energy intake of the steers. Animal performance appeared to be related to climatic factors over the entire annual range. Average daily gain and feed per unit gain were significantly correlated with mean ambient temperatures (r = 0.74 and −0.85, respectively), days below −23 C (r = −0.74 and 0.86), windchill (r = −0.73 and 0.82) and dewpoint (r = 0.74 and −0.83). Voluntary feed intake was markedly lower in winter than during the onset of colder weather in the fall. Cattle fed in the 90 coldest days required an extra 220 kg feed to reach market weight. Winter climatic conditions, therefore, have a marked adverse effect on full-fed feedlot cattle in Western Canada, even when the animals are well bedded and sheltered from wind.
COMPARISON OF SEVERAL WHEAT CULTIVARS AND A BARLEY CULTIVAR IN DIETS FOR YOUNG PIGS
Authors: BOWLAND J. P.
Published: March 2010

Two 10-wk experiments with eight weanling individually-fed pigs per treatment, starting at 5.6 to 7.5 kg liveweight, were conducted to compare No. 1 Canada Western Red Spring milling wheats, Manitou and Neepawa; No. 1 Utility (feed) wheats, Pitic 62, Glenlea, unlicensed white UM607A, unlicensed purple PFW606A; and feed barley BT609. All diets were supplemented with the same level of soybean meal and complete mineral and vitamin mixes. There were no significant differences in feed intake, rate of gain or efficiency of feed conversion among the treatments in either experiment, suggesting that the milling wheats, utility wheats and barley tested in this study have similar feeding value for young pigs. Carcass measurements did not differ between treatments in the first experiment, where pigs were fed to market weight on a standard diet after the 10-wk experimental period. In the first experiment, a diet based on Pitic 62 as the sole cereal had superior digestible energy (DE) and metabolizable energy (ME) coefficients to one based on Manitou, with Glenlea being intermediate. In the second experiment, diets based on Neepawa, Glenlea, white or purple utility wheats did not differ in DE or ME, but the barley-based diet had a lower DE and ME. Differences in dietary DE or ME were not reflected in live pig performance. DE and ME determinations on the cereals using the additive method with an additional four pigs per treatment indicated an average DE and ME (dry-matter basis) for wheat of 3,782 and 3,561 kcal/kg, and for BT609 barley of 3,670 and 3,489 kcal/kg, respectively. In the second experiment, there were significant differences between some of the wheats in DE and ME coefficients.
VITAMIN E AND HIGH OR LOW ERUCIC ACID RAPESEED OILS IN BROILER DIETS
Authors: VOGTMANN H. , CLANDININ D. R.
Published: March 2010

Regular rapeseed oil (RSO) from rapeseed containing approximately 25% erucic acid (C22:1) and low erucic acid rapeseed oils (LEAR) containing approximately 2.5% C22:1 prepared from the Oro (ORO and hydrogenated Oro oil, HORO) and Span (SPO) varieties of rapeseed were compared against soybean oil (SBO) or lard (LA) in diets for broilers. Two diets were formulated from each oil or fat, one containing no supplementary vitamin E, the other containing 30 mg/kg of supplementary vitamin E. Each ration was fed to two groups of 10 broiler-type chicks from day-old to 8 wk of age. Growth, lipid content and fatty acid composition of heart, liver and spleen tissues and plasma cholesterol levels were studied. Average body weight was highest in the chickens fed the SBO-, LA-, ORO- or HORO-containing diets, intermediate for SPO and lowest for the RSO-containing diet. Inclusion of supplementary vitamin E in the oil or fat-containing diets improved the growth rate in all cases. However, vitamin E status did not appear to be related to the deleterious effects reported with feeding high levels of rapeseed oil. No treatment effects were noted on the total lipid concentrations in heart and liver tissue. The total lipid concentration in the spleen was somewhat higher in chickens fed RSO than in those fed the other oils. RSO led to a relatively high, while LEAR oils led to minimal, tissue incorporation of C22: 1. Erucic acid concentration was highest in adipose tissue (9.2%), followed by breast muscle (6.8%), spleen (5.9%), cardiac tissue (4.8%) and liver (2.6%). Plasma cholesterol concentrations (PC) were highest in the chickens fed the RSO- and SPO-containing diets (122 mg % and 134 mg %, respectively); the other oils led to lower PC levels (approximately 100 mg %). It appears that the liver tissue can metabolize C22: 1 better than the other body tissues studied, perhaps by increased oxidation or by increased transport as cholesterol esters.
COMPARISON OF LOW GLUCOSINOLATE RAPESEED MEAL, COMMERCIAL RAPESEED MEAL AND SOYBEAN MEAL AS PROTEIN SUPPLEMENTS FOR GROWING PIGS
Authors: BOWLAND J. P.
Published: March 2010

Thirty-six crossbred pigs, equally divided between gilts and barrows, were fed from an average of 6 wk of age to market weight on three dietary treatments. Isonitrogenous, isocaloric diets were supplemented with either soybean meal (SBM), low glucosinolate rapeseed meal (RSM) from Brassica napus cv. Bronowski or commercial RSM of B. campestris origin. Metabolic studies were conducted at average weights of 14 and 31 kg and there were no significant differences in coefficients for digestible energy, metabolizable energy, digestible nitrogen or nitrogen retention between treatments, between sexes, or between periods. During the first 6 wk of the experiment and for the overall experiment, there was a difference between sexes in their response to low glucosinolate RSM. Barrows gained at a similar rate when fed diets supplemented with either SBM or low glucosinolate RSM, but more slowly on diets supplemented with commercial RSM. Gilts gained more slowly when fed either RSM than when fed a SBM-supplemented diet. The results suggest that there may be a factor, other than glucosinolates, present in RSM that tends to depress performance of gilts but not of barrows. This depression arising from either source of RSM was not associated with digestibility of energy or nitrogen or with nitrogen retention.
A LINEAR PROGRAMMING MODEL FOR BEEF CATTLE PRODUCTION
Authors: WILTON J. W. , MORRIS C. A. , LEIGH A.O. , JENSON E. A. , PFEIFFER W. C.
Published: March 2010

A linear programming model is defined in detail to describe an on-farm integrated beef production enterprise. The model includes cropping, feeding and breeding activities with their requirements for land, labor, animal housing and crop storage facilities. Net energy and digestible protein equations are used prior to the model construction to determine the nutrient requirements for cows, replacement heifers, feedlot heifers and steers, given weights and growth rates in young animals proportional to mature cow weights. A method for identifying the distribution of animals across different age groups is also described. Three enterprises with purebred cows of different mature size, each under typical Ontario farm conditions, are analyzed and interpreted.
A VERSATILE RESPIRATORY PATTERN ANALYZER FOR STUDIES OF ENERGY METABOLISM OF LIVESTOCK
Authors: YOUNG B. A. , KERRIGAN B. , CHRISTOPHERSON R. J.
Published: March 2010

A respiratory pattern analyzer for livestock is described. Continuous measurements can be made of oxygen consumption and respiratory output of carbon dioxide, methane and carbon-14, from which rates of heat production can be estimated by indirect calorimetry. The apparatus was designed on the basis of four modules (respiratory gas collection; gas flow and monitoring; gas sampling and analyses; recording) which can be operated independently or as integrated systems. The module components are duplicated in different forms to permit flexibility and ease of operation in studies on livestock subject to various thermal environments and experimental situations.
CLINICAL CHEMISTRY OF GRAIN-FED CATTLE. II. LIVER FUNCTION
Authors: BIDE R. W. , DORWARD W. J.
Published: March 2010

The rate of plasma clearance of bilirubin (BCR), as a test of liver function, was followed in three hay-fed and four grain-fed Hereford steers over the first 77 days of a 106-day feeding period. The grain diet was 90% steam rolled barley, 5% beet pulp pellets and 5% of a protein/mineral/vitamin concentrate given together with a hay supplement of 0.9 kg/head/day. The grain was introduced slowly over a 10-day period. Fluctuations in hematocrit values occurred during the adaptation to the grain diet. Periodic episodes of markedly reduced liver function occurred synchronously in test animals during the introduction of the grain diet. Similar episodes of reduced liver function were observed with decreasing frequency and severity as the feeding progressed. After 25 days of grain feeding, loss of synchrony also occurred, so that high values were observed in only one test animal at any one time. As the feeding period progressed, the time required for the distribution and equilibration of the bilirubin in the blood increased in the grain-fed animals causing interference with the BCR tests. The effects on liver function indicated a reduction in the efficiency of the liver which probably contributes to pathologic conditions in feedlot cattle.
INFLUENCE OF COLD EXPOSURE AND DIET CHANGE ON THE TRACE ELEMENT COMPOSITION OF HAIR FROM SHORTHORN CATTLE
Authors: HIDIROGLOU M. , SPURR D. T.
Published: March 2010

Sixteen yearling steers were divided into two groups of eight. Group I was wintered outside, while group II was wintered in a barn. Both groups were fed whole-crop barley silage during the winter and turned out to pasture in early spring. Manganese, copper, zinc and selenium concentrations were determined in hair samples from all steers at intervals of 2 wk over a period of 46 wk. No significant differences were found in the trace element contents of hair between the two groups. There was a significant effect of season on hair concentrations of Mn, Cu and Zn, possibly related to the lower concentrations of these elements in barley silage than in pasture grass. Se content was low in both diets. Mn, Cu and Zn levels in the hair decreased during the winter period and increased when the animals were turned out to pasture. Se content of the hair decreased during the experiment, probably as a result of maintaining the animals on a low selenium diet throughout the study. Variation among animals was large, suggesting that caution should be used in attributing low levels of trace minerals in the hair to inadequate dietary supplies.
INFLUENCE ON SOME RUMEN AND BLOOD PARAMETERS OF FEEDING ACETOHYDROXAMIC ACID IN A UREA-CONTAINING RATION FOR LAMBS
Authors: JONES G. A. , MILLIGAN J. D.
Published: March 2010

A 4 × 4 latin square design experiment, involving four fistulated Dorset–Columbia crossbred lambs, was used to determine the effects of feeding the urease inhibitor acetohydroxamic acid (AHA) with a urea-containing ration on some parameters of the rumen fermentation and blood. AHA, administered in the feed at concentrations up to and including 1.5%, markedly depressed rumen urease activity and the peak concentration of rumen ammonia. The maximum AHA concentration achieved in the rumen solution was 32.29 ± 14.26 mg per 100 ml, and thereafter the concentration dropped by 66% during the next 2 h. No evidence was found for an effect of AHA upon rumen pH, viable bacterial count, total protozoal count, total volatile fatty acid concentration, molar ratios of acetate, propionate and n-butyrate, or upon blood urea-nitrogen concentration. Traces of AHA were found in peripheral blood both 1 and 3 h after feeding, showing that AHA is absorbed from the ruminant digestive tract. It was concluded that AHA did not influence major parameters of the rumen fermentation at concentrations that effectively inhibited rumen urease.
EATING QUALITY OF BEEF FROM STEERS FED FULL OR RESTRICTED LEVELS OF MOISTURE-TREATED BARLEY
Authors: HAWRYSH Z. J. , HOWES A. D. , BERG R. T.
Published: March 2010

Comparisons were made of the eating quality of strip-loin (LD) steaks and eye of round (ST) roasts obtained from beef steers which were given finishing rations containing barley on a full-fed or restricted feeding basis. Cooking losses for LD steaks from both levels of feed were similar; however. ST roasts from full-fed animals had significantly higher total cooking and drip losses than did roasts from animals on restricted feed. Level of feeding did not influence volatile losses of ST roasts. Subjective evaluations of LD steaks indicated that there were no differences in eating quality characteristics attributable to level of feeding. Significant differences in the texture of ST roasts attributable to level of feed were observed. Although the flavor of roasts from animals given restricted levels of barley was significantly lower than those of samples from full-fed animals, judges rated the juiciness of roasts from animals on restricted levels of feed significantly higher than similar samples from full-fed animals. Level of feed did not affect other payability characteristics of roasts. Shear values and press fluid yields were not influenced by level of feed.
ASCORBIC ACID METABOLISM IN SWINE. THE EFFECTS OF FREQUENCY OF FEEDING AND LEVEL OF SUPPLEMENTARY ASCORBIC ACID ON SWINE FED VARIOUS ENERGY LEVELS
Authors: BROWN R. G. , BUCHANAN-SMITH J. G. , SHARMA V. D.
Published: March 2010

The effects of supplementary ascorbic acid and frequency of feeding on the performance of 3-wk-old, castrated, male swine fed 140, 240 and 340 kcal/kg W0.75 of metabolizable energy (ME) was investigated using a 3 × 3 × 2 factorial experiment. Frequency of feeding had no influence on the growth rate within any one energy group. Supplementary ascorbic acid up to the level of 1,000 mg per day produced improvement in growth rates at all levels of ME intake. The improvement in rate of growth appeared not to be due to water retention because there were no differences in creatinine excretion rates (per kg of body weight per day) between any of the groups. Ascorbic acid supplementation at the rate of 1,000 mg/day resulted in an increased proportion of the label from glucose-U-14C incorporated into the saponifiable fraction of an adipose tissue biopsy from the group fed a daily ration of 140 kcal ME/kg W0.75 in five equal amounts during the day. Supplementary ascorbic acid appeared to have no other effects on lipid metabolism. Excretion of ascorbic acid was significantly increased when there was an increased ME intake and an increased level of vitamin supplementation. These observations confirm an earlier report that the ascorbic acid available to the swine is a function of the energy level in the diet. It is suggested that observations (vide supra) made in ME-deprived animals may be due to decreased amounts of ascorbic acid physiologically available to the pig.
UREA UTILIZATION IN GROWING AWASI LAMBS FED HIGH OR LOW ROUGHAGE PELLETED DIETS
Authors: BHATTACHARYA A. N. , ASGHAR M. N.
Published: March 2010

Two experiments were conducted with 36 young Awasi wether lambs to study the effect of urea supplementation at 2.5%, as a complete soybean meal replacement in control pelleted rations containing 30 or 50% barley hay, on nitrogen utilization, blood and rumen metabolites and activity in the tissue of certain urea cycle enzymes; supplementary data on feed intake, growth rate, feed efficiency and activity of some urea cycle enzymes were also collected only for lambs on 30% roughage pellets with or without urea. Experiment 1 involved 20 lambs and consisted of a growth trial and two sets of digestion and metabolism trials during a period of 120 days, while experiment 2 included the enzyme assay along with a 60-day growth trial and one set of three metabolism trials with 16 lambs, half of which belonged to the urea group and were treated with a drench of ammonium bicarbonate during a 45-day preweaning period before the experiment. All growth trials were with the low roughage ration only. Lambs fed urea-supplemented ration in experiment 1 showed improved growth rate (P < 0.05) and feed efficiency without any change in ad libitum feed intake as compared to the soybean control, and the improvement was mostly during the last 60 days. Urea supplementation increased crude protein and ether extract digestibility in both high and low roughage rations while it increased crude fiber digestibility in the high, but decreased it in the low, roughage ration. Daily nitrogen retention increased significantly (P < 0.05) in the urea group fed low roughage diet without changing the efficiency of utilization of absorbed nitrogen, while the retention by the high roughage urea group did not differ significantly from the control (P > 0.05). Ammonia and urea concentrations in the blood showed significant increases as a result of urea feeding. In experiment 2, daily gain, feed intake, feed efficiency, nutrient digestibility and nitrogen balance did not show any statistically (P > 0.05) significant difference between treatments, but trends in the values were similar to those observed in experiment 1. No difference in the activities of urea cycle enzymes could be detected in the liver, rumen and intestinal tissues between treatments.