bluuebunny/crossref_metadata_2025 huggingface dataset:
BREED-DIRECT, BREED-MATERNAL AND NONADDITIVE GENETIC EFFECTS FOR PREWEANING TRAITS IN CROSSBRED CALVES
Authors: CUNNINGHAM B. E. , MAGEE W. T.
Published: March 2010

Two sets of preweaning records of calves were used to estimate breed-direct, breed-maternal, and nonadditive genetic effects. Three groups were represented in both sets of data: a straightbred Hereford line; a rotational crossbreeding line using Angus, Charolais, Hereford, and Simmental breeds; and a rotational crossbreeding line using Angus, Hereford, Holstein-Friesian, and Simmental breeds. Dataset 1 (DS1) consisted of calf records from 1972 to 1976 while dataset 2 (DS2) comprised records from 1978 to 1982. The breeds were the same in both datasets except the Simmental breed was not used in DS1. The traits studied in both DS1 and DS2 were birth weight (BWT), preweaning average daily gain (ADG), and weaning weight (WWT). Calving difficulty (CD) and percent assisted births (%AB) were studied in DS1. A multiple regression procedure was used to estimate breed-direct and breed-maternal effects, as well as average individual and maternal heterosis. Compared to the Hereford breed, breed-direct effects for BWT were negative while breed-maternal effects were positive for all breeds. Estimates of breed-direct and maternal effects for CD and %AB indicated that Simmental breeding would increase dystocia directly, but could decrease dystocia maternally. All breed-maternal effects for CD and %AB were negative compared to the Hereford breed. For ADG and WWT, breed-direct effects for Simmental, Charolais, and Holstein-Friesian were positive in DS2 but Charolais direct effects in DS1 were negative compared to Hereford. Estimates of average individual and maternal heterosis for the traits studied agreed with reported literature values except for weaning weight in DS2, where a large negative estimate (P < 0.10) for average WWT maternal heterosis was obtained. Key words: Beef cattle, crossbreeding, direct effects, maternal effects, heterosis
RECOVERY OF NEONATAL LAMBS FROM HYPOTHERMIA WITH THERMAL ASSISTANCE
Authors: ROBINSON J. B. , YOUNG B. A.
Published: March 2010

Metabolic heat production and body core temperature were measured in 12 newborn lambs (4.7 ± 0.2 kg) prior to and during the induction of acute hypothermia (Tc = 30 °C), as well as during recovery to euthermia. Hypothermia was induced by immersion in 14–28 °C water. Rewarming was achieved by one of three procedures: (A) immersion of the lambs in warm water (38 °C); (B) exposure of the lambs in an air environment to a 250-watt infrared heat lamp; or (C) wrapping the lambs in a cotton cloth. Prehypothermia resting heat production was 4.3 ± 0.2 W kg−1. During the induction of hypothermia, summit metabolic heat production was 20.9 ± 0.5 W kg−1; however, as core temperature decreased from 35 to 31 °C, maximum metabolic rate declined by 1.33 W kg−1 per °C decline in core temperature. Recovery of the lambs to an euthermic state was achieved in 28, 38 and 50 ± 1.8 min in the warm water, infrared lamp and cotton cloth rewarming treatments with metabolic costs during recovery of 21.2, 33.2 and 40.6 ± 0.8 kJ kg−1, respectively. Recovery of hypothermic lambs in 38 °C water resulted in a thermal contribution to body heat content from the water and a substantial reduction in recovery time and in metabolic effort by the lambs. Key words: Hypothermia, rewarming, metabolic heat, supplemental heat, neonates, lambs
EFFICACY OF COMPUDOSE® AS AN ANABOLIC IMPLANT FOR GROWING-FINISHING FEEDLOT HEIFERS
Authors: STOBBS L. A. , NELSON J. R. , GRIMSON R. E. , STILBORN R. P. , MOWAT D. N. , RICHARDS J. E. , NICHOLSON H. H.
Published: March 2010

A series of three trials was conducted to determine the effect of a controlled release silicone rubber implant containing 24 mg estradiol 17β (Compudose®) on the weight gain and feed efficiency of feedlot heifers. A total of 352 heifers with an average initial weight of 245 kg were used in the three studies. The heifers were fed a high roughage (corn silage or chopped brome alfalfa hay) grower diet followed by either a 75% barley (two trials) or 50% high moisture corn (one trial) finishing diet. Heifers implanted with Compudose® tended (P < 0.10) to have higher average daily gains (6.7%) and improved conversion of feed to liveweight gain (4.1%) compared to nonimplanted heifers. Mean carcass weight of implanted heifers was 5.0 kg heavier (P < 0.05) than control heifers. Fat thickness was 0.11 cm less (P < 0.05) and rib-eye area 3.6 cm2 larger (P < 0.05) in the Compudose® versus the control groups. Compudose was efficacious in improving carcass quality of growing and finishing feedlot heifers and resulted in non-significant improvements in rate of gain and feed conversion. Key words: Compudose, estradiol, implant, heifers, anabolic
THE EFFECTS OF FAT SUPPLEMENTATION ON ILEAL VERSUS FECAL FAT DIGESTIBILITIES, PERFORMANCE AND BODY COMPOSITION OF WEANED PIGS
Authors: ENDRES B. , AHERNE F. X. , OZIMEK L. , SPICER H.
Published: March 2010

Two experiments were conducted with 28-d-old pigs to study the effects of 0 or 8% added fat to the diet when constant nutrient to energy ratios were maintained. In exp. 1, 24 pigs were assigned to one of six treatments. Pigs were fed either ad libitum or restricted. Digestibility values were determined using fecal and terminal ileum collection methods. Only apparent ether extract digestibility increased (P < 0.001) with the addition of fat to the diet. Ether extract digestibility coefficients determined by the ileal collection method were significantly larger (P < 0.001) than those determined by fecal collection. In contrast apparent energy, dry matter and crude protein digestibilities based on ileal collection were significantly lower than the equivalent digestibilities based on fecal collection. The second experiment compared the performance and carcass composition of pigs fed the same diets as in exp. 1. Pigs 7 d after weaning contained less fat (P < 0.01), more water (P < 0.001) and more protein (P < 0.01) than pigs at weaning. Carcass composition of the pigs 7 d after weaning and at 20 kg liveweight were similar (P > 0.05). Feed conversion efficiency was improved (P < 0.001) by the addition of fat to the diet. Key words: Weaned pigs, fat, digestibility, performance, body composition
YIELD AND COMPOSITION OF EDIBLE MEAT FROM MALE BROILERS AS INFLUENCED BY DIETARY PROTEIN LEVEL AND AMINO ACID SUPPLEMENTATION
Authors: SUMMERS J. D. , LEESON S. , SPRATT DIANE
Published: March 2010

Two experiments were undertaken to investigate yield and composition of various carcass parts when male broilers were fed diets varying in level of dietary protein and methionine and lysine supplementation. Birds fed a low protein diet (16%) showed little difference in performance or carcass characteristics when compared with a similar diet supplemented with 0.17% DL-methionine. A comparison of diets containing 17, 20 and 23% dietary protein demonstrated that birds on the 17% diet had less carcass protein and more carcass fat than the higher protein diets. However, supplementation of the 17% diet with methionine and lysine resulted in weight gain and carcass composition values similar to the higher protein diets. At similar body weights, birds fed the higher levels of protein or birds fed diets supplemented with essential amino acids resulted in higher levels of carcass protein accretion. Breast meat accounted for approximately 30% of total carcass meat; however, it would contribute close to 50% of total edible carcass protein. Since breast meat makes up such a substantial portion of edible carcass protein, a reliable estimate of carcass protein deposition should be able to be made from sampling one half of the breast. Key words: Carcass composition, protein deposition, broilers
BRAHMAN-BRITISH BEEF CATTLE CROSSES IN CANADA. II. POSTWEANING GROWTH AND CARCASS CHARACTERISTICS
Authors: PETERS H. F. , VESELY J. A.
Published: March 2010

Brahman-British beef cattle crosses in Canada (F1 hybrids) out-gained contemporary Herefords under both winter and summer range conditions. Brahman × Hereford, Brahman × Angus and Brahman × Shorthorn steers marketed off grass at 2.5 yr of age surpassed Herefords by 61 – 64 kg in cold carcass weight, 3.9 – 4.8% in dressed carcass yield, and 4 – 6 cm2 in longissimus dorsi area per 250 kg of carcass. The 1/4-Brahman progenies from matings of Hereford bulls with F1 cows did not differ significantly from Herefords in year-long postweaning gain, either under Alberta range conditions or under summer grazing and limited winter feeding conditions at Ottawa, Ontario. Hereford × (Brahman × Hereford) backcross calves gained less than Herefords but averaged 16 kg heavier in cold carcass weight because of greater initial (weaning) weight and a higher dressing percentage. There was no difference between the crosses (F1 hybrids and back-crosses) and Herefords in carcass grade. The major benefit of the Brahman-British cattle crosses resulted from the superior performance of the F1 hybrids, expressed as a marked superiority in growth rate of the F1 steers and heifers and a greater weight-for-age of the 1/4-Brahman progenies of F1 cows. Key words: Brahman, Hereford, Angus, Shorthorn, crossbreeding
THE EFFECT OF ESTRADIOL BENZOATE AND BOAR EXPOSURE ON THE OCCURRENCE OF ESTRUS AND OVULATION IN THE GILT
Authors: DYCK G. W.
Published: March 2010

The efficacy of estradiolbenzoate (EB) and exposure to mature boars as means of stimulating estrus and ovulation in gilts was determined on a total of 333 Lacombe gilts. The gilts were placed on the experiment at an average age of 160 d either in the winter (January and February) or summer (July and August) of 2 yr. They were slaughtered either 8 – 12 d after being observed in estrus or after 200 d of age if they were not observed in estrus. A higher percentage of EB-treated than control gilts were in estrus by 200 d of age (87.4 vs. 58.6%, P < 0.01). For the EB vs. control gilts detected at their first estrus, the number of days to estrus after 160 d of age was shorter (4.5 ± 0.1 vs. 16.9 ± 1.1 d, P < 0.01). In the control gilts, exposure to mature boars and season had no significant effect on the number of gilts in estrus or days to first estrus. In comparison with control gilts, EB produced the following additional effects: more gilts in estrus without ovulation (32.7 vs. 15.1%, P < 0.05); a reduction in ovulation rate (6.2 ± 0.4 vs. 12.8 ± 0.5, P < 0.01); and more gilts with cystic follicles (11.9 vs. 0.8%, P < 0.01). Thus, while EB stimulated estrus at an earlier age than exposure to mature boars, the effects on the ovary suggest that breeding at the EB stimulated estrus would not be desirable. Key words: Estradiolbenzoate, boar exposure, estrus, ovulation
EFFECTS OF PSYCHOLOGICAL STRESS, ACUTE COLD STRESS, AND DIET ON FORESTOMACH CONTRACTIONS IN CATTLE
Authors: LIRETTE A. , KELLY J. M. , MILLIGAN L. P. , CHRISTOPHERSON R. J.
Published: March 2010

Studies were made on forestomach contraction frequencies as affected by diet (brome hay, alfalfa hay, alfalfa silage and barley concentrate diet), acute cold stress and acute psychological stress. Four 15-mo-old steers fitted with ruminal fistulae were used in a 4 × 4 Latin square design. Diets did not influence contractile frequencies of the forestomachs, and did not interact with the effects of the stresses. Acute cold stress and psychological stress both produced significant increases of forestomach contraction frequencies and of heart rate. Key words: Cold stress, psychological stress, forestomach contractions, heart rate
INFLUENCE OF IONOPHORE ADDITION TO ROUGHAGE AND HIGH-CONCENTRATE DIETS ON PORTAL BLOOD FLOW AND NET NUTRIENT FLUX IN CATTLE
Authors: HARMON D. L. , AVERY T. B. , HUNTINGTON G. B. , REYNOLDS P. J.
Published: March 2010

Two experiments using cattle with chronic hepatic-portal and arterial catheters were conducted to investigate effects of ionophore addition to roughage and high-concentrate diets on net nutrient flux across portal-drained viscera. Monensin and salinomycin added to a high-concentrate diet fed to three beef heifers in a Latin square design (exp. 1) increased the net portal flux of propionate (P < 0.05) and glutamate (P < 0.05) with a tendency for increased portal blood flow. Two beef steers (exp. 2) were fed alfalfa with monensin (300 mg d−1) for 22 d prior to dietary monensin and samples were taken on days −3, 0, 1,2, 4, 9, 16, 32, and 35 relative to monensin removal. Portal blood flow and gut oxygen consumption decreased (P < 0.05) following monensin removal until day 9, then remained relatively constant. Use of glucose by portal-drained viscera decreased (P < 0.05) until day 16, then returned towards initial values, while net appearance of L-lactate decreased linearly (P < 0.05). After monensin removal from the diet, the net portal flux of L-lactate, ammonia-N, acetate, propionate, isobutyrate, and 3-methylbutyrate were reduced (P < 0.05). These reductions were largely the result of decreased portal blood flow. In both experiments, dietary ionophores affected net flux across portal-drained viscera for several metabolites. These changes may differ, however, with roughage level and ionophore fed. Key words: Bovine, ionophore, absorption, blood flow
THE RELATIONSHIP OF RUMEN CATIONS AND SOLUBLE PROTEIN WITH PREDISPOSITION OF CATTLE TO ALFALFA BLOAT
Authors: HALL J. W. , MAJAK W. , RYSWYK A. L. VAN , KALNIN C. M. , HOWARTH R. E.
Published: March 2010

Rumen-fistulated cattle were fed fresh alfalfa herbage daily during two growing seasons. Samples of rumen fluid were collected daily prior to feeding and the frothiness of the rumen fluid was assessed. Concentrations of soluble protein nitrogen in the rumen fluid were higher in animals that subsequently bloated than in those that did not (P < 0.01). There was no relation between soluble protein nitrogen and the occurrence of foam in the rumen prior to feeding. The concentrations of Na and K in the rumen fluid were negatively correlated. Bloat was associated with a low concentration of Na and a high concentration of K (P < 0.01). Concentrations of Ca and Mg were lower than those of the two monovalent ions but were also positively associated with bloat (P < 0.01). The high concentration of chlorophyll associated with a predisposition to bloat may be the result of a colloidal aggregation of chloroplast particles stabilized by cations. Key words: Pasture bloat, alfalfa, chlorophyll, ions, cattle
EFFECT OF AMOUNT AND LENGTH OF ALFALFA HAY IN DIETS CONTAINING BARLEY OR CORN ON SITE OF DIGESTION AND RUMEN MICROBIAL PROTEIN SYNTHESIS IN DAIRY COWS
Authors: RODE L. M. , SATTER L. D.
Published: March 2010

Eight lactating Holstein cows fitted with simple cannulae in the rumen and proximal duodenum were used in a 2 × 2 × 2 factorial experiment in a randomized complete block design. The factors studied were: (1) forage length (full bloom alfalfa hay, long or chopped); (2) forage level in the total ration (25 or 75%); and (3) type of grain in the concentrate mixes (barley or corn). Organic matter (OM) intake was not affected by level of forage or grain type but was greater (P < 0.05) with chopped hay than with long hay. Apparent total digestion of OM increased (P < 0.01) from 59.7 to 68.1% as forage in the diet decreased from 75 to 25%, but site of digestion was unaffected. Flow to the duodenum of nonammonia-N, feed N, and microbial N were unaffected by forage level, forage length, or grain type. No differences in main effects were observed between corn and barley but interactions between grain type and forage length or amount indicate that type of grain had an influence upon site of OM digestion and flow of nonammonia-N and microbial N from the rumen. Efficiency of microbial protein synthesis (MPS) was positively associated with turnover rate of rumen solids regardless of liquid dilution rate. When no change in turnover rate of solids occurred, efficiency of microbial protein synthesis increased in association with increases in turnover rate of liquid. Key words: Lactation, cattle, bacteria, alfalfa, duodenum, rumen
BLOOD SERUM CONCENTRATIONS OF FOLATES AND VITAMIN B12 DURING GROWTH PERIOD OF WHITE VEAL CALVES
Authors: GIRARD C. L. , MATTE J. J.
Published: March 2010

Variations of hemoglobin, hematocrit, folates and vitamin B12 concentrations in blood serum were studied during the rearing period of 62 rapidly growing (1.6 kg d−1) white veal calves. The animals were fed exclusively with milk replacers during the 110 d rearing period. Hemoglobin and hematocrit decreased linearly with time (P < 0.0001). There was an age effect (P < 0.0001) on serum concentrations of vitamin B12 and folates during the rearing period. The serum concentrations of vitamin B12 increased during the first 3 wk from 214.8 pg mL−1 to 422.6 pg mL−1 and then were stable until the 13th week of the rearing period. Serum concentrations of folates decreased during the 3 wk from 11.3 ng mL−1 to 5.1 ng mL−1 and then increased to reach a stable concentration of about 14 ng mL−1 from 6 wk to the end of the rearing period. Males had significantly lower serum folates concentrations than females (P < 0.0001) but their serum profiles during the rearing period were similar. Further studies will be necessary to elucidate the consequences of a decrease in serum folates during the starting period on the growth performance of white veal calves. Key words: White veal calves, blood serum folates, vitamin B12
EFFECTS OF BARLEY HULLS, DIETARY PROTEIN LEVEL AND WEIGHT OF PIG ON DIGESTIBILITY OF CANOLA MEAL FED TO FINISHING PIGS
Authors: BELL J. M. , KEITH M. O.
Published: March 2010

A factorial digestibility experiment with three dietary levels of canola meal (CM) (0, 15, 30%), two levels of barley hulls (0, 25%) and two basal diets (approximately 10 and 19% crude protein, CP) was conducted using crossbred pigs over the weight range 45 – 90 kg. Diets contained 0.5% chromium oxide as a fecal marker. Inclusion of barley hulls improved the apparent digestibility of dietary CP (83.3% with hulls vs. 81.9% without hulls) and of corn CP (74% for corn, 76% for corn + hulls). True digestibility of CP in corn was also improved (75% for corn, 90% for corn + hulls). The energy and CP components of barley hulls were 40 and 57% digestible, respectively. The digestibility values for CM were: CP 80% (apparent) and 85% (true); energy 68%; nonprotein energy 55% and these were not affected by the presence of barley hulls. Digestibility improved as the pigs matured; each 10-kg weight increase was associated with 0.65 and 0.37 percentage units increase in digestibility of CP and energy, respectively, but these values may be lower than those normally encountered because of the use of casein for adjusting dietary CP levels in this experiment. It is suggested the barley hulls may possess two opposing properties, one that depresses digestibility of protein by increasing metabolic fecal nitrogen output and which is related to the neutral detergent fiber component, and another that in some way enhances the digestibility of protein. Key words: Canola meal, barley hulls, protein level, digestibility, pigs
FEEDING AND METABOLISM TRIALS, AND ASSESSMENT OF CARCASS AND MEAT QUALITY FOR GROWING-FINISHING PIGS FED NAKED OATS (Avena nuda)
Authors: FRIEND D. W. , FORTIN A. , KRAMER J. K. G. , POSTE L. M. , BUTLER G. , BURROWS V. D.
Published: March 2010

Forty-eight Yorkshire pigs (barrows and gilts), about 24 kg body weight, were fed three diets: a control diet containing corn-soybean meal with minerals and vitamins added (Diet 0), the same diet in which naked oats (Avena nuda L. 'Tibor') replaced approximately 50% of the corn and soybean meal (Diet 50) and a diet containing 95.4% naked oats plus the mineral and vitamin supplements (Diet 100). The diets were pelleted and given ad libitum to the pigs which were penned individually until marketed at 90 ± 5 kg bodyweight. The left side of the carcass was used for carcass quality determinations, meat quality (sensory evaluation) assessment and backfat samples for fatty acid analysis. Eighteen other Yorkshire pigs were used in metabolism trials to determine digestible and metabolizable energy and nitrogen values and nitrogen balances when fed the three test diets. Energy values for urine were determined with freeze-dried samples combusted in polyethylene bags using an adiabatic bomb calorimeter. The diets (DM basis) contained about 18% crude protein and 18 MJ kg−1 energy; Diet 100 was higher in ether extract (5.5%) and lower in ADF (1.7%). Pigs fed Diet 50 gained weight faster than pigs fed either of the two other diets, the overall effect being accounted for mainly by differences shown by the barrows. Feed data showed a similar pattern with higher daily intake and fewer days to market for Diet 50 pigs. A lower yield of lean meat was obtained from pigs fed Diet 100, an observation also supported by increased depth of loin fat and carcass ether extract. The fatty acids palmitic, oleic and linoleic represented 12, 23 and 59% of the total in the control diet, compared with 18, 40 and 37% in Diet 100. This dietary change was reflected in a carcass decrease of linoleic acid from 14 (control) to 13% (Diet 100). The dietary level of naked oats had a significant and beneficial effect on sensory evaluation scores for the pork roasts; flavor, tenderness and juiciness scores were highest for pigs fed Diet 100. The apparent digestible energy value for Diet 100 (17.3 M J kg−1) was the highest as was the apparent metabolizable energy value (17 MJ kg−1). Correction of the AME for the energy of retained N reduced the value by 2.35%. The nitrogen retention value was approximately 10% lower for the 95.4% naked oat diet than for the corn-soybean control diet. The study indicated by feeding and metabolism trials that, although growing-finishing diets containing a high proportion of naked oats are likely to be of high energy and protein value, they are limited in feeding value by an amino acid imbalance due probably to lysine insufficiency. Key words: Naked oats, metabolism, carcass, meat quality, fatty acids, pigs
BIOTIN BIOAVAILABILITY FROM PROTEIN SUPPLEMENTS AND CEREAL GRAINS FOR WEANLING PIGS
Authors: MISIR R. , BLAIR R.
Published: March 2010

The biological availability of biotin in canola meal (CM), cereal grain, cereal grain plus CM, and soybean meal (SBM) was estimated, using 140 pigs in the 10- to 20-kg weight range. In exp. I, pigs (six/treatment) were individually housed and fed a basal casein-cornstarch diet with 0, 50, 100, 150, 200 or 250 μg d-biotin kg−1 to generate data for a dose-response curve based on plasma biotin concentration. Other pigs were fed CM, SBM or soyprotein isolate (SPI) included in the diet. In exp. II, pigs were housed in pairs and four pairs were fed diets based on cereal grain or cereal grain plus CM. Results (exp. I) showed a higher correlation between daily biotin intake and plasma biotin (r = 0.835, P < 0.01) than on growth rate (r = 0.627, P < 0.05). The regression for plasma biotin (Y) on biotin intake (X) computed from the linear portion of the curve (i.e., 0-200 μg added biotin kg−1) was[Formula: see text]Biotin bioavailability in various feedstuffs was highest for corn (101.2%), followed by SBM (85.5%), CM (70.9%), and wheat (33.3%), triticale (25.9%), sorghum (25.1%) and barley (24.0%). Key words: Biotin bioavailability, protein supplements, cereal grains, swine
POTENTIAL OF FIELD PEA (Pisum sativum) SCREENINGS AS FEED FOR MARKET PIGS
Authors: CASTELL A. G. , NEDEN L. R. , MOUNT K.
Published: March 2010

Partial or complete replacement of soybean meal by screenings from two cultivars (B.C. Blues, Century) as 0, 11, 22 or 33% of barley diets (16% crude protein) did not reduce growth rate, efficiency of feed conversion or carcass grade of pigs fed ad libitum from 26 to 94 kg liveweight. Key words: Pig, pea, screenings, growth, carcass
VARIATION IN PIGLET WEIGHTS: WEIGHT GAINS IN THE FTRST DAYS AFTER BIRTH AND THEIR RELATIONSHIP WITH LATER PERFORMANCE
Authors: THOMPSON B. K. , FRASER DAVID
Published: March 2010

Piglets from 42 litters of Yorkshire sows were weighed 0, 1, 2, 3, 4, 5, 7, 10, and 14 d after farrowing in order to explore the highly variable weight gains during the first 2 wk after birth. All litters were adjusted to 10–12 piglets by fostering. Litters differed greatly in average gain per piglet during the first 3 d after farrowing, with litter means ranging from 5 to 227 g d−1 per piglet for the 3-d period. Gains during days 0–3 tended to be somewhat lower if the sow had a high body temperature during these days, but the correlation was not high (r = −0.35; P < 0.05). Compared to litters with high average gains during days 0–3, litters with low gains during this period continued to have lower average gains during days 3–14 (P < 0.05) and had higher within-litter variation in gain (P < 0.01). On a within-litter basis, weight gain during the first days after farrowing was only weakly correlated with the day 14 weight of individual piglets. Low average gain by a litter in the first 3 d after birth is probably due to low initial milk yield by the sow, and likely indicates a poor start to the sow's lactation. Early identification of litters with low initial gains might allow remedial action to reduce the problems of high mortality and low, variable gains later in lactation. Key words: Piglet, body weight, suckling behavior, agalactia, mortality
GENETIC EFFECTS ON POSTWEANING GROWTH OF THREE-WAY CROSS BEEF CATTLE
Authors: RAHNEFELD G. W. , WEISS G. M. , FREDEEN H. T. , NEWMAN J. A. , LAWSON J. E.
Published: March 2010

Genetic effects on postweaning growth traits were evaluated for 3592 crossbred steers and heifers fed at two locations, Brandon, Manitoba and Lacombe, Alberta during a 6-yr period (1973–1978). The calves were sired by Chianina (Chi), Charolais (C), Limousin (L) and Simmental (S) bulls mated to 10 F1 dam-crosses representing the Hereford × Angus (HA) and nine dam-cross combinations produced by mating C, S and L sires with H, A and Shorthorn (N) females. Progeny rankings by terminal sire breed for weight on-test were C = Chi = S > L. For the trait 140-d postweaning average daily gain, progeny rankings were C > Chi = S, C = Chi > L and Chi > S > L. The progeny from the majority of "exotic" cross-dams were heavier on-test, and had higher postweaning average daily gain than progeny from HA dams. Ranking of dam-crosses according to their breed of sire (DS) for the trait weight on-test were S > C > L. The DS comparisons for postweaning average daily gain were C > S > L. The ranking of dam-crosses by breed of dam's dam, for on-test weight and postweaning average daily gain were N > H = A. Genetic interactions (terminal sire by breed cross of dam) were absent. Genotype environment interactions involving breed of terminal sire with year, sex and location were found for weight on-test and postweaning average daily gain. All resulted from changes in the magnitude of breed of sire differences, not from changes in sire rankings. Key words: Cattle, breeds, cross breeding, growth
EFFECT OF STAGE OF LACTATION AND OF DAILY INJECTIONS OF GRF AND TRF ON SERUM CORTISOL IN LACTATING SOWS
Authors: ROBERT S. , PASSILLÉ A.-M. B. DE , ST-PIERRE N. , PELLETIER G. , DUBREUIL P. , GAUDREAU P. , BRAZEAU P.
Published: March 2010

Two experiments were conducted with 51 primiparous sows to determine the effects of stage of lactation and treatment with growth hormone-releasing factor (GRF) and thyrotropin-releasing factor (TRF) on serum cortisol concentrations and pulse profiles. Animals were injected with either saline, GRF (20 μg kg−1 in both experiments), TRF (1 μg kg−1 and 9 μg kg−1 in exps. 1 and 2, respectively) or GRF-TRF (administered in combination at the levels mentioned above). Peptides were given subcutaneously twice daily between days 5 and 25 postpartum. In exp. 1, mean cortisol levels were higher on day 5 than on subsequent sampling days due to higher peak amplitudes. This result is discussed with respect to stress. Mean serum cortisol concentrations did not vary significantly between days 5, 15 and 25 of lactation in exp. 2. No evidence of a morning peak and late afternoon low was observed in cortisol secretion of sows during lactation. Finally, none of the hypothalamic factor treatments altered the basal serum concentrations or the peak amplitudes of cortisol. However, in exp. 2, the frequency of cortisol peaks was lower for the GRF- and TRF-treated sows than for the control and GRF-TRF sows. Key words: Cortisol, GRF, TRF, lactation, sows
EFFECT OF TWO-MONTH TREATMENT WITH GROWTH HORMONE-RELEASING FACTOR ON MILK PRODUCTION AND PLASMA CONSTITUENTS IN DAIRY COWS
Authors: LAPIERRE H. , PELLETIER G. , PETITCLERC D. , DUBREUIL P. , MORISSET J. , GAUDREAU P. , COUTURE Y. , BRAZEAU P.
Published: March 2010

Seventeen dairy cows averaging 252 d of lactation were used to study the effect of long-term treatment with a human growth hormone-releasing factor (hGRF(1–29)NH2) on lactational performance and concentration of plasma constituents. For 57 d, the cows received a daily subcutaneous injection of either saline (S, n = 8) or 10 μg kg−1 BW of hGRF(1–29)NH2 (GRF, n = 9). Milk production and feed intake were recorded daily, while milk composition was determined weekly. Treatment with GRF increased 4% fat-corrected milk yield (13.9 vs. 15.8 kg d−1), and fat yield, (0.58 vs. 0.66 kg d−1). It did not affect protein yield (0.46 vs. 0.52 kg d−1), or feed intake (17.2 vs. 17.8 kg d−1) (means of the 57 d of treatment, S vs. GRF). The GRF-treated cows gained more weight than the control cows, 5.5 vs. 4.2%, respectively. Blood samples were collected hourly, from 2 h before to 8 h after the daily injection on d 1, 15, 29, 43 and 57, to determine plasma constituent concentrations. GRF treatment decreased calcium and cholesterol concentrations, but increased free fatty acids concentration. All constituents measured remained within the normal range. The weights of the cows and their calves and milk yield (14 first wk postpartum) at the subsequent lactation were not affected by previous GRF treatment. In conclusion, treatment with GRF during the last 2 mo of lactation increased milk production and altered levels of some plasma constituents without any detrimental effect on the subsequent lactation. Key words: Growth hormone-releasing factor, milk production, plasma constituents, cows (dairy)
EFFECT OF TANNINS ON THE DIGESTIBILITY OF TWO ISOSYNTHETIC STRAINS OF BIRDSFOOT TREFOIL (Lotus corniculatus L.) USING IN VITRO AND IN SACCO TECHNIQUES
Authors: CHIQUETTE J. , CHENG K.-J. , COSTERTON J. W. , MILLIGAN L. P.
Published: March 2010

Two new isosynthetic strains of birdsfoot trefoil (Lotus corniculatus L.), containing low or high concentrations of tannin, were tested using in vitro and in sacco digestibility techniques. The high tannin (HT) strain contained an average of five times more tannin on a dry matter basis, than the low tannin (LT) strain. After 24-h in vitro digestion, by a rumen inoculum, there was less (P < 0.01) dry matter disappearance (45.7 vs. 54.4%) from the HT strain. Also, the development of gas pressure was lower (P < 0.01) and production of volatile fatty acids less (P < 0.05) with the HT strain than with the LT strain. Average dry matter loss from four replicated nylon bags was also lower (P < 0.01) for the HT strain than for the LT strain after 8, 12, and 24 h of incubation in rumen. These data indicate that a LT strain of birdsfoot trefoil might improve the forage digestibility. Key words: Birdsfoot trefoil, tannin, digestibility
EFFECT OF STRUCTURAL AND CHEMICAL FACTORS OF FORAGES ON POTENTIALLY DIGESTIBLE FIBER, INTAKE, AND TRUE DIGESTIBILITY BY RUMINANTS
Authors: GIRARD V. , DUPUIS G.
Published: March 2010

In view of the large variation found in plant cell wall digestibilities with ruminants, an attempt was made to group 124 feeds into different lignification classes (clusters) on the basis of chemical characteristics. Each feed cluster was described using a structural coefficient [Formula: see text] that related the potentially digestible fiber (PDF, %) to the ratio between lignin and cell wall volume. The optimum number of clusters was determined iteratively by performing a regression of the apparent digestibility of dry matter at maintenance level (DDM1, %) against the PDF and cell soluble (SOL, %) contents of feeds. The [Formula: see text] coefficients varied from 0.05 (grains, N = 13) to 1.85 (corn silage, N = 3) and increased with the maturity of the grasses from 0.88 (legumes, vegetative cool season grasses, N = 26) to 1.33 (mature, cool season grasses, N = 19). Predicted PDF were closely correlated (r > 0.9, P < 0.01) to in vitro cell wall disappearances (IVCWD). Apparently digestible cell wall in four grasses and four legumes increased linearly with 96-h IVCWD and standard error (SE) was similar to the SE of predicted apparent digestible SOL from SOL concentrations. Assuming that similarity between SE could be also observed in larger samples, PDF and SOL were used in summative equations to predict apparent dry matter digestibility. DDM1 discounted for intake (DDM1 – 4, %) was regressed against SOL and PDF concentrations of 87 feeds:[Formula: see text]with ds and df, the true digestibilities of SOL and PDF. Estimates of ds and df were 0.98 and 0.95 for a zero-production (maintenance) level of intake, and 0.91 and 0.79 for an intake level four times maintenance. Since the true digestibility of the PDF component was only 4% – 13% lower than that of the cell soluble component, the concentration of PDF in cell wall was the major determinant in the variation in apparent digestibility of forages. Key words: lignin, neutral detergent fiber, true digestibility, cluster analysis, feeds
INFLUENCE OF TYPE OF SILAGE BAG ON CHEMICAL COMPOSITION OF ALFALFA SILAGE
Authors: ROBINSON P. H. , KENNELLY J. J. , MATHISON G. W.
Published: March 2010

Second-cut alfalfa in mid-bloom was ensiled in 3.6-m-diameter silage bags to give about 20 t of material per bag. Six bag types were utilized and each was replicated thrice. Bags evaluated were: PolyStor, Silobag, CIL-SB2, CIL-SB3, Visqueen, and AgBag. Ensiled material was assayed for chemical composition, including fermentation products, 2 and 14 mo after ensiling. Silage was also evaluated qualitatively based on smell (ammonia and silage aroma) and appearance (color, spoilage, consistency, and mold) at 8 and 14 mo. At 2 mo, all silages were judged to have met minimum requirements of good silage. However, significant differences in chemical composition suggest potential silage feeding value could be rated:[Formula: see text]Qualitative evaluation after 8 mo suggested silage quality was similar to that determined at 2 mo. However, after 14 mo one bag type contained silage which did not meet minimum requirements for good silage. The unacceptable silage, from PolyStor bags, had high pH as well as low concentrations of lactic acid and total alcohols. Within the five silage types judged to have met minimum standards, there was insufficient difference in chemical composition to suggest differences in potential feeding value. Silage in all bags showed significant deterioration between 8 and 14 mo and it is suggested that to ensure high-quality feed, silage should be fed prior to the summer following bag filling. Key words: Silage bags, silage quality, alfalfa
THE EFFECT OF SOW NUTRITION DURING LACTATION ON THE INCIDENCE AND SEVERITY OF OSTEOCHONDROSIS IN THEIR OFFSPRING AT 100 kg LIVEWEIGHT
Authors: WALKER B. , AHERNE F. X.
Published: March 2010

Eighty crossbred pigs at weaning were selected from 20, third-parity sows which had been fed either an adequate or restricted (50% of adequate) level of energy and protein during lactation for three consecutive parities. Pigs, in groups of four, were housed in 2.4-m × 1.5-m concrete-floored pens and fed standard starter, grower and finisher diets (19, 16 and 14% crude protein, respectively) ad libitum. Locomotory ability was recorded prior to slaughter at 100 kg liveweight. Sites in the elbow joint and distal ulna physis were examined for evidence of osteochondrosis. Pigs from restricted-fed sows were lighter at birth and weaning (P < 0.01) and had significantly higher rates of liveweight gain during the grower (7–60 kg) period than pigs from adequately fed sows. Locomotory ability, morphology under light microscopy and overall incidence of osteochondrotic lesions did not differ (P > 0.05) between pigs from the two sow nutrition regimes, nor between sexes. Osteochondrotic lesion score in the distal ulna physis was higher (P < 0.01) in pigs from restricted-fed sows and was weakly correlated (r = 0.16, P < 0.001) with the extent of maternal weight loss over the lactation period. Lesion scores for the lateral humeral condyle and proximal ulna were higher (P < 0.05) for pigs from adequately fed sows. The possibility of an etiological difference between physeal and articular-epiphyseal lesions of osteochondrosis is discussed. Maternal nutrition can not be ruled out as a factor in the etiology of physeal lesions. Key words: Swine, osteochondrosis, maternal nutrition, lactation
PANCREATIC CANNULATION OF YOUNG PIGS FOR LONG-TERM STUDY OF EXOCRINE PANCREATIC FUNCTION
Authors: PIERZYNOWSKI S. G. , WESTRÖM B. R. , KARLSSON B. W. , NILSSON B. , SVENDSEN J.
Published: March 2010

A surgical model and an experimental procedure were developed in the pig to enable the long-term collection of pancreatic juice under natural conditions from the first week of life until several weeks after weaning. Purebred Swedish Landrace pigs of varying ages were operated on as follows: at 3–4 d of age (n = 3) and returned to the sow; at 3 wk of age (n = 5), returned to the sow for 1 wk and then weaned; at 4–5 wk of age (n = 3), weaned on the day of surgery, and at 8–9 wk of age (n = 6). The pancreatic duct was catheterized; the catheter was exteriorized through an abdominal cannula and connected to a re-entrant perforated duodenal T-cannula. Using this model, long-term experiments were performed on alternate days for periods of 1–12 wk, and pancreatic juice was collected before and after feeding. The growth of the pigs did not appear to be seriously disturbed; postmortem examination did not reveal any major problems at the operation sites. The procedure permitted the collection of pure unactivated pancreatic juice, and did not appear to interfere with normal physiological responses to both feeding and hormonal stimulation with cholecystokinin (CCK) and secretin. Our observations indicated that this animal model may be used to study the postnatal development of the exocrine pancreas and the adaptation processes taking place when the feeding regime is changed at weaning. Key words: Pig, exocrine pancreas, chronic cannulation, development
THE EFFECT OF HOUSING FACILITIES AND BOAR EXPOSURE AFTER WEANING ON THE INCIDENCE OF POSTLACTATIONAL ANESTRUS IN PRIMIPAROUS SOWS
Authors: DYCK G. W.
Published: March 2010

Two studies were carried out to determine the effect of the type of housing and exposure to mature boars after weaning on the incidence of postlactational anestrus in primiparous Lacombe sows. The incidence of anestrus was higher in sows housed in pairs in confinement as compared to housing in groups in outside lots (64.0 vs. 39.5%, respectively; P < 0.10). Exposure of sows to mature boars after weaning had no effect on the incidence of anestrus, but the duration of estrus was shorter (P < 0.01) for sows with constant boar exposure as compared to minimum boar exposure. Key words: Sows, anestrus, boar exposure, housing
MINERAL AND NITRATE CONTENT OF SWINE DRINKING-WATER IN FOUR QUEBEC REGIONS
Authors: FLIPOT P.M. , OUELLET G.
Published: March 2010

A water quality survey of 83 hog farms was conducted in four swine-producing regions of Quebec. Samples were collected from the tap in the piggeries. The mineral content of drinking water varied considerably from farm to farm within regions. In general, drinking water was alkaline and nitrate concentrations were below toxic levels. The drinking water alone could supply up to 20% of a gestating sow's mineral requirements. In some cases (3.6 and 23%), sodium and copper requirements would be exceeded. Key words: Hog, drinking water, minerals, nitrates
EFFECTS OF DATE OF WEANING ON SUBSEQUENT PERFORMANCE OF BEEF COWS AND THEIR FEMALE CALVES
Authors: MAKARECHIAN M. , KUBISCH H.-M. , PRICE M. A.
Published: March 2010

1233 April/May born calves were weaned either on 30 Sept. (EW) or 31 Oct. (LW) to assess the effects of weaning date on subsequent performance of their dams and female calves. Cows in the EW group lost less weight than those in the LW group in the month of October (0.003 vs. 0.48 kg d−1, P < 0.05). Dam's breed group, year and the interaction between year and age of dam also had significant effects on weight change during October. Cows generally lost weight between weaning and the next calving and the two weaning groups were similar in body weight at calving and reproductive performance. The reproductive performance of the EW and LW female calves were also quite similar. It can be concluded that weaning April/May born calves in September rather than October would not influence the subsequent production of the dams or their female calves, but would probably reduce their maintenance requirements as they enter the cold season in better condition. Key words: Weaning date, beef cows, reproduction, weight changes
ECONOMIC VALUE OF FEEDER CALVES BETWEEN BREED CROSSES
Authors: SMITH ELWIN G. , RAHNEFELD GUNTHER W.
Published: March 2010

Data on growth and feed conversion efficiency for different breed cross steer calves were analyzed to determine whether there were differences between breed crosses in their economic value as feeder calves. An economic model was used to calculate the value of the steer calves. An analysis of covariance was used to determine whether the value of feeder calves differed between breed crosses for calves of equal weight. Calves were produced by mating Charolais (C), Simmental (S), Limousin (L), and Chianina (Chi) terminal sires to 10 different types of first-cross dams. Nine of the first-cross dam crosses were produced by mating C, S, and L to Hereford (H), Angus (A), and Shorthorn (N) dams and the tenth cross was Hereford-Angus (HA). The cows were maintained and the calves raised and fed to slaughter at Brandon, Manitoba. Three methods of pricing the finished steers (liveweight, hot carcass weight, and weight of the lean tissue) were used to calculate feeder calf value. There were significant differences (P < 0.01) between breeds of the terminal sires and between breed crosses of dams for all three pricing methods. For feeder calf values, the terminal sire progeny breeds ranked Chi ≥ C ≥ S > L for liveweight pricing, Chi > C > S = L for hot carcass weight pricing, and Chi > C ≥ L ≥ S for lean weight pricing. Ranking of the progeny by dam cross indicated CN = LN ≥ CH = SN ≥ CA = LA ≥ SH = SA = LH ≥ HA for liveweight pricing, LN ≥ CN = SN ≥ CH ≥ CA = LA ≥ SH = SA ≥ LH ≥ HA for hot carcass weight pricing, and LN = CN ≥ CH = CA = LA = SN ≥ SH = SA = LH > HA for lean weight pricing. The primary determinants of the differences in feeder calf value between breed crosses were differences in carcass yield and grade, rate of gain on feed, and feed efficiency. Key words: Economic, breed cross, feeder steer, feeder value, lean yield
THE INFLUENCE OF EXOGENOUS GROWTH HORMONE ON OVULATION RATE IN GILTS
Authors: KIRKWOOD R. N. , THACKER P. A. , GOONERATNE A. D. , GUEDO B. L. , LAARVELD B.
Published: March 2010

A total of 32 prepubertal gilts of Yorkshire and Landrace breeding were selected at 138 d and fed ad libitum a 16.2% crude protein diet formulated to provide 13.1 MJ DE kg−1. From selection until the end of second estrus, the gilts were exposed to a boar for 30 min d−1 to facilitate the detection of pubertal and second estrous periods. From 14 d after puberty, the gilts received daily injections of either porcine growth hormone at 90 μg kg−1 body weight (GH; n = 20) or vehicle (CT; n = 12) until 24 h after the onset of second estrus and were then killed 9 d later to determine ovulation rate. Gilts not displaying a second estrus by 24 day after puberty were considered anestrus and the injection regime was halted. Anestrous gilts were killed 30–32 d after puberty and their ovaries examined for the presence of corpora albicantia and the absence of corpora lutea. Blood samples were obtained from all gilts at 14, 17, and 20 d after puberty. There was no treatment effect on the duration of the estrous cycle (20.8 vs. 21.3 d for GH and CT, respectively), but while all CT gilts cycled normally, only 55% of the GH gilts had a second estrus (P < 0.01). In those gilts having a second estrus, the daily injection of growth hormone increased ovulation rate (14.3 vs. 12.4 for GH and CT respectively; P < 0.03). Serum type 1 insulin-like growth factor (IGF-1) concentrations were higher (P < 0.001) in GH than in CT gilts, but there was no difference between cycling and anestrous GH gilts. We suggest that the effect of growth hormone on ovulation rate was mediated by increased secretion of IGF-1. The etiology of the high incidence of anestrus is, however, not known. Key words: Gilts, growth hormone, ovulation rate
THE COMPARATIVE PHYSIOLOGICAL DEVELOPMENT OF THE REPRODUCTIVE AND ADRENAL AXIS OF THE GILT FROM WEANING TO PUBERTY
Authors: EVANS F. D. , CHRISTOPHERSON R. J. , AHERNE F. X.
Published: March 2010

The objective of this study was to examine the development of the reproductive axis of the gilt with respect to development of the adrenal glands. Groups of five gilts each were slaughtered at 4-wk intervals from 4 to 20 wk of age. Organ weights as well as activity of the adrenal glands were determined by histometry to determine nuclear to cellular volume ratios and thickness of zones of the cortex. Weights of the heart, lungs, spleen, kidneys, pineal, thyroid and adrenals were found to increase with age while relative weight of these organs was constant or decreasing. In contrast, weight and relative weight of the whole reproductive tract, oviducts and uterus showed growth spurts, first at 16 wk and later at 28 wk of age. The ovaries had one growth spurt at 16 wk of age. An increase at 12–16 wk was also evident in profiles of estradiol and LH determined from blood samples collected from another group of gilts sampled at weekly intervals until first estrus (207.8 ± 3.3 d, mean ± SEM). Measurement of relative nuclear volume and thickness of the adrenal cortex zonation during development failed to provide any evidence to support the hypothesis that an increase in activity or growth of the adrenal gland is responsible for the growth spurts in the reproductive axis during development. Key words: Adrenal gland, adrenal axis, development, gilt, reproductive axis
EVALUATION OF TIMOTHY CULTIVARS FOR VOLUNTARY INTAKE AND NUTRIENT COMPONENTS
Authors: MASON W. N. , FLIPOT P. M.
Published: March 2010

Five timothy (Phleum pratense L.) cultivars, Clair, Champ, Milton, Climax and Bounty, were harvested at first flower stage during 2 consecutive years and in the regrowth for 1 yr. The forages were each offered as hay to 15 young rams to evaluate voluntary intake. Five animals were used to determine initial harvest dry matter digestibility. The cultivars varied significantly in voluntary intake at first flower stage. The highest intake (g kg−0.75 d−1) averaged for the years was obtained in the early cultivar Champ (65.9), which was 10% more than that of the medium-late cultivar Climax. The cultivars did not differ significantly in dry matter digestibility. In the regrowth, the relative intakes of the cultivars were essentially reversed from that of the initial harvest. The voluntary intake was substantially higher but the differences among forages were less marked. Climax regrowth voluntary intake was higher (P < 0.05) than all cultivars, except Bounty. A 15% range in digestible dry matter intake was present among cultivars. The ranking of the culivars for digestible dry matter was different than for dry matter yield. Key words: Timothy, Phleum pratense L., voluntary intake, dry matter digestibility