bluuebunny/crossref_metadata_2025 huggingface dataset:
POSTWEANING VAGINAL MUCUS CONDUCTIVITY AND BREEDING PERFORMANCE AT ARTIFICIAL INSEMINATION IN SWINE
Authors: CHARUEST JEAN-PIERRE , DUFOUR JACQUES J. , SAVOIE YVAN , RICHARD YVONNE M.
Published: March 2010

Two experiments were conducted to test the efficiency of using vaginal mucus conductivity measurements in sows to fix the breeding time for artificial insemination (Al). The apparatus used was the Heat Detector No 113 from Mitogiken Ltd. (Group Sumimoto, Toronto). In exp. 1, 57 crossbred sows were measured three times daily from 1 to 5 d after weaning (day 0) in order to characterize the pattern of vaginal mucus conductivity before estrus. In all females onset of estrus was checked twice daily in the presence of a sexually mature boar. Sow vaginal mucus conductivity readings (12 unit scale) averaged 4.1 units at weaning and 7.4 units at estrus. Only 60% of the sows reached the manufacturer's recommendation of 7–9 units at estrus. Conductivity increased by an average of three units between weaning and estrus in 62% of the sows. In exp. 2,201 crossbred sows were assigned randomly according to parity number to three groups. The first group was bred by Al when the sows showed a three-unit increase in vaginal mucus conductivity after weaning, without estrus detection by the boar. The two other groups of sows were checked once daily for onset of estrus using a mature boar, with a group bred by natural service and the other by Al. There was a large amount of variation between and within sows in absolute vaginal mucus conductivity readings. Only 29.3% of sows were inseminated at a reading of 7–9 units while 53.7% of the sows showed a differential of + 3 units after weaning, among which 50% reached a reading of 7–9 units at breeding. Sixteen (41.5%) sows showed behavioral estrus signs at an avg. conductivity reading of 4.0 units, without reaching the + 3 unit differential in conductivity. Conception rate and litter size of sows bred at a + 3 unit differential in conductivity were lower than the two groups of sows which were heat checked with a boar. No difference was observed among the latter two groups. The results indicated that vaginal mucus conductivity alone, without the use of a boar is not a reliable tool to fix the proper time to inseminate sows. Key words: Vaginal conductivity, artificial insemination, estrus, postweaning, sow
EFFECT OF PORCINE GROWTH HORMONE-RELEASING FACTOR (1-29)NH2 AND THYROTROPIN-RELEASING FACTOR ON PIG GROWTH PERFORMANCE
Authors: DUBREUIL P. , MORISSET J. , COUTURE Y. , PELLETIER G. , PETITCLERC D. , LAPIERRE H. , POMMIER S. , GAUDREAU P. , BRAZEAU P.
Published: March 2010

Sixty female pigs were divided into four treatment groups to evaluate the effect of chronic treatment with porcine growth hormone-releasing factor (pGRF), thyrotropin-releasing factor (TRF) and their combination on growth performance of Yorkshire-Landrace pigs. Animals were injected with either saline, pGRF(1-29)NH2 at 15 μg kg−1 BW, TRF at 6 μg kg−1 BW, or pGRF plus TRF at doses previously mentioned, according to a 2 × 2 factorial design, using three pens of five pigs per treatment. Subcutaneous injections were made twice daily from 19.4 ± 0.8 to 95.2 ± 0.5 kg BW. Treatments did not affect (P > 0.05) average daily weight gain, feed consumption, feed efficiency or age at slaughter. TRF had no effect (P > 0.05) on carcass and blood variables except for reducing lung weight (P < 0.05) and increasing blood-urea nitrogen after 4 wk of treatment. GRF reduced (P < 0.01) backfat thickness at the level of the first thoracic rib, 13th thoracic rib, last lumbar vertebra and at 6.5 cm from the dorsal mid-line at the level of the 13th rib. Furthermore, pGRF increased carcass length, loin eye area at the 13th rib, lung weight and kidney weight. Blood glucose and free fatty acid concentrations were not affected (P > 0.05) by treatments. No significant pGRF × TRF interaction was observed for any measured variables. At the doses injected, TRF and pGRF did not modify growth variables, while pGRF positively affected carcass characteristics by reducing lipid content and increasing carcass length as well as loin eye area. Key words: Growth hormone-releasing factor, thyrotropin-releasing factor, pig, growth performance, carcass characteristics
REPRODUCTIVE PERFORMANCE OVER FOUR PARITIES OF GILTS STIMULATED TO EARLY ESTRUS AND MATED AT FIRST, SECOND OR THIRD OBSERVED ESTRUS
Authors: YOUNG L. G. , KING G. J. , WALTON J. S. , McMILLAN I. , KLEVORICK M.
Published: March 2010

One hundred and eighty-seven gilts that were moved, regrouped and exposed to a mature boar at approximately 140 ± 3 d of age and subsequently farrowed to assigned mating at first, second, or third observed estrus as gilts were used to evaluate reproductive performance over four parities. Over the four parities, the average number of litters per initial sow (3.22–3.25); the average litter size 21 d postfarrow (8.3 to 8.6); the average total number of piglets weaned per initial sow (26.9 – 27.7); the number of sows completing four parities (37–40); the average litter weight at 21 d postfarrow (146–148 kg) were similar for each mating group. The age difference of 36.8 d at first mating between those mated on first or third estrus as gilts was maintained until 28 d postfarrowing after the fourth parity (37.1 d). Overall, reproductive performance after four parities was similar for gilts mated at first, second or third observed estrus. Key words: Pigs, reproduction, mating, longevity
GESTATION ENERGY AND REPRODUCTION IN SOWS OVER FOUR PARITIES
Authors: YOUNG L. G. , KING G. J. , WALTON J. S. , McMILLAN I. , KLEVORICK M. , SHAW J.
Published: March 2010

One hundred and eighty-seven gilts that conceived at first, second or third estrus after 140 d of age and that had a litter at 21 d post-farrow were fed three gestation energy levels 22.2, 29.2 and 36.2 MJ DE d−1 for four parities to assess the effect of gestation energy level on reproductive performance and longevity. All sows were fed the same lactation diet to appetite twice per day. Gestation energy level did not have a consistent effect on the number of piglets per litter. There was a small linear increase in piglet birth weight as gestation energy level increased. However, piglets from sows fed the medium level of energy were heaviest at 21 d. Weight and backfat thickness of sows tended to change with the level of food intake. Sows that ate more in gestation tended to eat less in lactation. There were significantly fewer sows fed the low gestation energy level completing parities three and four and this was the major factor accounting for fewer total piglets at 21 d post-farrow. Many of the sows not completing the trial on this treatment had 10 mm or less P2 backfat. The major reason for sow removal was due to sows not pregnant at the expected time of farrowing. Estimates were made of feed and energy intake during gestation and lactation consistent with good reproductive performance. Key words: Pigs, reproduction, energy, longevity
THE PERFORMANCE OF PREGNANT BEEF COWS RELYING ON SNOW AS A WATER SOURCE
Authors: DEGEN A. A. , YOUNG B. A.
Published: March 2010

Body mass change, water influx, metabolic heat production and rectal temperature were measured in four pregnant beef cows offered only snow as a water source (snow cows) and in four pregnant beef cows that also had access to heated water (water cows). The study was carried out during winter (December to March) in Alberta, Canada. There was no difference between treatment groups in any of these measurements indicating that the snow cows were obtaining adequate water to satisfy their requirements and that no added nutrient energy was required to melt the snow and bring the water to body temperature. Milk yield in the two groups, measured in early spring when water was available to all cows, was similar as was the growth rate of the calves. Milk yield averaged 8.2 kg d−1 during weeks 2–4 of lactation and 4.6 kg d−1 during weeks 14–16. Average daily gain from birth to weaning (6 mo) of calves suckling the snow cows was 0.74 kg and of calves suckling the water cows was 0.70 kg. It was concluded that there was no detrimental effect of withholding liquid water from pregnant beef cows when snow is available and that cows can use snow as their only water source for lengthy periods of time during winter. Key words: Pregnant cows, snow, water, water influx, metabolic heat production
EFFECT OF A GROWTH HORMONE-RELEASING FACTOR ANALOG ON GROWTH HORMONE, INSULIN-LIKE GROWTH FACTOR 1 AND MILK PRODUCTION IN DAIRY COWS
Authors: LAPIERRE H. , PELLETIER G. , PETITCLERC D. , GAUDREAU P. , BRAZEAU P. , MOWLES T. F. , DUBREUIL P.
Published: March 2010

In a first experiment, 21 cows (98 d in lactation, 609 kg BW) were randomly used to determine the dose-response release of growth hormone (GH) to [desamino-Tyr1, D-Ala2, Ala15] growth hormone-releasing factor (1–29)NH2 analog (GRF-A; 0, 0.12, 0.37, 1.11 and 3.33 μg kg−1 BW) or to human growth hormone-releasing factor (1–29)NH2 (GRF; 3.33 and 10.00 μg kg−1 BW) after s.c. administration. The interaction (P < 0.01) between the two releasing factors and the doses on GH concentrations indicated that the analog was more potent than the original molecule; at the 3.33 μg kg−1 BW dose, the analog elicited a 3.5 times higher GH response than GRF. In a second experiment, the effects of daily s.c. injections for 10 d of either saline, GRF (10 μg kg−1 BW) or GRF-A (0.6 or 1.8 μg kg−1 BW) on GH concentrations and lactational performance were determined using 32 cows (n = 8 per treatment) averaging 91 d in lactation and subjected to a random block design. The three releasing factor treatments similarly increased GH concentrations measured during the 8 h following the injection on d 1 and 10. GRF at the dose of 10 μg kg−1 BW and the analog at the doses of 0.6 and 1.8 μg kg−1 BW increased milk yield by 9.6, 11.7 and 17.6%, respectively, when compared to the control; both releasing factors had no effect on milk composition. Insulin-like growth factor I concentrations were increased 8 h after the last injection, from 73.4 ng mL−1 in control cows to an average of 107.6 ng mL−1 in treated cows. Results show that the [desamino-Tyr1, D-Ala2, Ala15] human growth hormone-releasing factor (1–29)NH2 analog is more potent than human growth hormone-releasing factor (1–29)NH2 in stimulating GH release and milk production in dairy cows. Key words: Growth hormone-releasing factor, analog, growth hormone, milk production, insulin-like growth factor 1, cows (dairy)
EFFECTS OF BULL EXPOSURE ON POSTPARTUM INTERVAL AND REPRODUCTIVE PERFORMANCE IN BEEF COWS
Authors: NAASZ C. D. , MILLER H. L.
Published: March 2010

One hundred and thirteen spring calving beef cows were utilized to study the effect of bull exposure during the early postpartum period on return to estrus and fertility. In the spring of 1985 and 1986, cows were randomly exposed to epididymectomized bulls (BE) 3–7 d after calving until beginning of the breeding season (n = 37, 1985; n = 20, 1986) or not exposed to bulls (NE) (n = 35, 1985; n = 21, 1986). Cows were observed for estrus twice daily beginning approximately 4 wk after the start of calving until synchronization. Estrous cycles of all cows were synchronized with Syncro-Mate B® (SMB) and cows inseminated 48 h after implant removal without regard to estrus. Calves were removed for 48 h following implant removal. Each year a group of cows was randomly selected from the BE group (n = 8, 1985; n = 7, 1986) and NE group (n = 8, 1985; n = 7, 1986) and cannulated at estrus after SMB implant removal. Blood samples were collected at 15-min intervals for 2 h and every 2 h for 46 h for determination of LH concentrations. Bull-exposed cows returned to estrus 16 d earlier (P < 0.01) than NE cows in 1985. In 1986, no difference was observed between BE and NE cows for days from calving to first estrus. The percentage of cows exhibiting estrus prior to synchronization was greater (P < 0.01) for BE cows than NE cows in 1985 (78 vs. 17%) and in 1986 (75 vs. 24%). Peak LH levels did not differ between treatment but were different between years. Time to the LH peak following SMB implant removal and calf removal did not differ between treatment and year. Conception rates were not influenced by bull exposure or year. Days from calving to conception were also not influenced by bull exposure. Key words: Bull exposure, cows, postpartum interval, reproduction
ACTIVITY OF ASPARTATE AMINOTRANSFERASE ISOENZYMES WITH RELATION TO BODY WEIGHT AND PYRIDOXAL 5′-PHOSPHATE ACTIVITY IN THE MALIGNANT HYPERTHERMIA-SUSCEPTIBLE PIG
Authors: DOIZÉ F. , ROUX I. , DeROTH L.
Published: March 2010

The objective of the present study was to demonstrate in pigs the influence of halothane susceptibility on the activities of aspartate aminotransferase (AST) and its isoenzymes (m-AST and c-AST) during the postweaning period. Furthermore, the effects of pyridoxal 5′-phosphate (PLP) addition to the reaction mixture was also investigated. Seven different body weight levels were considered (group 1, 10–20 kg; group 2, 21–30 kg; group 3, 31–40 kg; group 4, 41–50 kg; group 5, 51–60 kg; group 6, 61–70 kg; group 7, more than 70 kg). The halothane challenge test was used to determine the MH susceptibility. Significantly greater plasma total AST activity (P < 0.05) was found in the malignant hyperthermia-susceptible (SMH) pigs compared to the resistant (RMH) for body weight groups 4 and 7. The addition of PLP enhanced the activity of AST on an average of 28%, and a significant difference between SMH and RMH was found in body weight group 4. m-AST was not affected by growth and similar values were found in both RMH and SMH groups of pigs. The addition of PLP enhanced the m-AST activity by an average of 35%. The activity of c-AST and c-AST-PLP showed a similar pattern to that of total AST with or without the coenzyme. Plasma of SMH and RMH pigs contain some apoenzyme which can be reactivated by PLP. Overall, AST and c-AST are significantly higher in SMH pigs and their activities correlate with body weight. Key words: Malignant hyperthermia, pig, AST-isoenzyme
EFFECT OF SUPPLEMENTING SUMMER RANGES ON LACTATION AND GROWTH OF WAPITI (Cervus elaphus)
Authors: HUDSON R. J. , ADAMCZEWSKI J. Z.
Published: March 2010

The effect of nutritional supplementation with alfalfa-barley pellets (approximately 11 MJ ME kg DM−1) on milk production of wapiti hinds and growth of their calves was studied from birth in late May and early June until weaning in mid-September on aspen parkland ranges in central Alberta. Although supplemented hinds produced more milk at peak lactation (1080 vs. 883 g per nursing bout, P = 0.04) and may have gained slightly more weight (359 vs. 187 g d−1, P = 0.08) before the rut than their unsupplemented counterparts, growth of calves (870 g d−1) was unaffected by the nutritional treatment. Unsupplemented calves grazed more than supplemented calves (59 vs. 36% of the active period, P = 0.00) and this may have compensated for lower milk consumption. Supplemented hinds spent progressively less time grazing than unsupplemented hinds throughout the summer. This trial suggests that there are few benefits of supplementing lactating wapiti on appropriately-stocked parkland ranges in central Alberta during summer. Key words: Game farming, lactation, calves, growth, wapiti, elk
EFFECT OF RUMINAL MICROBIAL COLONIZATION ON CEREAL GRAIN DIGESTION
Authors: McALLISTER T. A. , RODE L. M. , MAJOR D. J. , CHENG K.-J. , BUCHANAN-SMITH J. G.
Published: March 2010

The objective of this study was to examine the microbial digestion and colonization of whole (W), halved (H) and quartered (Q) cereal grains within the rumen. Barley (Hordeum vulgare L.), maize (Zea mays L.), sorghum (Sorghum bicolor (L.) Moench), and wheat (Triticum aestivum L.) were placed in nylon bags in the rumen of a fistulated steer. In sacco DM disappearance (ISDMD) of W grain was lower (P < 0.001) than that of H or Q grain. Once sectioned, wheat was most susceptible to microbial digestion followed by barley, sorghum and maize, respectively. Scanning electron microscopy showed that microbial colonization of W grain was restricted to fractured areas of the pericarp. Fracturing of the pericarp is necessary to allow rumen bacteria to gain access to the rapidly digestible nutrients of the endosperm. Initial colonization (2 h) of the endosperm of H and Q grains by rumen bacteria tended to be between large starch granules. After 24 h of exposure in the rumen, the endosperm of barley, wheat and sorghum was colonized by a variety of rumen bacteria. In contrast, regions of the germ and horny endosperm in maize were not colonized. The sequential colonization of the endosperm, culminating in the establishment of complex microbial consortia, is required for the digestion of cereal grains. Key words: Cereal, rumen bacteria, digestion, processing, concentrate
YIELD, QUALITY AND PRESERVATION OF MOIST HAY SUBJECTED TO RAIN-FREE AND WEATHERED CONDITIONS
Authors: BARON V. S. , MATHISON G. W.
Published: March 2010

The effects of moisture level and a neutralized propionate preservative on yield, quality and preservation of rain-free and weathered alfalfa (Medicago sativa L.) hay were studied in separate trials. Moisture levels of 252, 185 and 138 g kg−1 in rain-free hay and 297, 211 and 180 g kg−1 in weathered hay were designated as High, Medium and Low, respectively. The weathered hay received 66 mm of rain at about 600 g kg−1 moisture and another 15 mm prior to baling at the Low moisture level. The preservative (680 g kg−1 propionic acid equivalent) was applied at 1.25 and 1.50% (wt wt−1) for rain-free and weathered hay, respectively. The High and Medium moisture level treatments had similar harvested dry matter (DM) yields in both rain-free and weathered hay. Rain-free hay DM yield at harvest was 6–9% higher for the High and Medium treatments than the Low moisture level, while for the weathered hay the Medium level was 3.0% higher (P < 0.05) than the Low moisture level. Poststorage forage qualities of the Low and Medium moisture level treatments were similar and higher than the High moisture treatment (P < 0.05) in rain-free hays, while the Medium level treatment was highest (P < 0.05) for forage quality in weathered hay. The Medium moisture level compared with Low moisture level resulted in 10.4, 10.6 and 15.8% higher yields of DM, in vitro digestible organic matter (IVDOM) and crude protein, respectively, in rain-free hay and 3.1, 6.3 and 5.7% higher, respectively, in weathered hay. The propionate was inconsistent in preventing DM loss during storage, but reduced temperature and mould count in both hay types. Application of 1.25 and 1.50% (wt wt−1) of propionate improved poststorage IVDOM by 2.0 and 3.6%; increased crude protein yield by 3.0 and 5.7% and IVDOM yield by 3.3 and 5.7%; reduced neutral detergent fiber by 5.4 and 7.6%; reduced acid detergent fiber by 5.4 and 7.1%; and reduced acid detergent insoluble nitrogen by 9 and 18% in rain-free and weathered hay, respectively. It is recommended that large round bales be harvested at moisture levels somewhat above 170 g kg−1 for both rain-free and weathered hay with or without a neutralized propionic acid preservative. Serious losses may occur above 250 g kg−1 moisture with or without the use of a preservative. Key words: Alfalfa, moist hay, neutralized propionate, large round bales, weathering, preservation
THE NUTRITIVE VALUE OF NAKED OATS FOR BROILER CHICKS AS AFFECTED BY DIETARY ADDITIONS OF OAT GUM, ENZYME, ANTIBIOTIC, BILE SALT AND FAT-SOLUBLE VITAMINS
Authors: CAVE N. A. , WOOD P. J. , BURROWS V. D.
Published: March 2010

Five experiments were conducted with broiler chicks to evaluate naked oat (NO) as a major dietary ingredient and to identify means of ameliorating its growth-depressing effects. Substituting naked oats at concentrations of 0–600 g kg−1 for corn in a broiler starter diet gave a dose-dependent decrease in weight gain and feed efficiency. Incorporation of β-D-glucanase into a NO diet increased growth of chicks presumed by decreasing β-glucan viscosity whereas increasing the β-glucan content of the diet by addition of oat gum or oat brans decreased rate of growth and feed efficiency. Autoclaving NO or supplementing a 600 g kg−1 NO diet with neomycin or penicillin increased weight gains, but feed efficiency effects were inconsistent. True metabolizable energy values for naked oats and oat bran as determined with chicks were 16.2 and 11.5 MJ g−1 dry matter, respectively. True availabilities of energy, ether extract and amino acids were reduced by, respectively, 10, 5 and up to 8% by addition of oat gum to naked oats and, 2.4, 24 and up to 8% by ethanol deactivation of oat bran enzymes. Supplementation of a NO diet with antibiotic, bile salt and water-miscible, fat-soluble vitamins in factorial combination demonstrated that reduced absorption of lipids, including fat-soluble vitamins may decrease energy values and growth in chicks fed naked oats. The β-glucan content of naked oats appears to be the factor responsible for poor utilization of the feedstuff by chicks. The effect of this factor was overcome by treatment with enzyme or to a lesser degree by dietary supplementation with antibiotics, bile salt or fat-soluble vitamins. Key words: Oat (naked), β-glucan, enzyme, autoclaving, bile salt, fat-soluble vitamin phytase, chick
THE REPRODUCTIVE EFFICIENCY OF GILTS FED VERY LOW LEVELS OF ZEARALENONE
Authors: FRIEND D. W. , TRENHOLM H. L. , HARTIN K. E. , FISER P. S. , THOMPSON B. K. , ASEM E. K. , TSANG B. K.
Published: March 2010

In the first of three experiments, 60 prepuberal gilts (12–13 wk old) were fed diets containing 0.01 (control), 0.16, 0.36, 0.47, 1.28 and 2.21 mg zearalenone (ZEN) kg−1 feed for 63 d. Vulvovaginitis occurred in some gilts fed the control diet; there was a trend (P < 0.01) towards heavier uteruses as the dietary level of ZEN increased. Experiment 2 involved 16 gilts allocated in pairs in noncontiguous pens and fed diets containing 0.01 and 2.21 mg ZEN kg−1 feed for 42 d. No control gilt exhibited vulvovaginitis when separated from a treated gilt by an unoccupied pen while all eight of the treated gilts showed vulvovaginitis. Results suggested that estrogenic metabolites in the urine of gilts eating ZEN-contaminated feed might, if ingested, induce vulvovaginitis in other untreated gilts. Experiment 3 involved 40 gilts and four diets (0.01, 0.36, 0.47 and 1.28 mg ZEN kg−1 feed). The gilts were bred and were necropsied between days 52 and 55 of pregnancy. The incidence of vulvovaginitis differed (P < 0.01) among diets, tending to increase with higher ZEN levels. Fewer gilts fed the two higher levels of ZEN could be bred than those fed the lower ZEN levels. Serum progesterone concentrations ranged from 0.1 to 0.6 ng mL−1 for prepubertal gilts, and from 22 to 29 ng mL−1 during early pregnancy. Fetal mortality, while not significantly different, was numerically less for the control gilts than for those fed the ZEN-treated diets. Feed intake and weight gain were not affected significantly, by the inclusion of zearalenone in any of the experiments. The data indicated that zearalenone did not have serious effects on the reproductive efficiency of young gilts at levels below 0.5 mg kg−1 feed. Key words: Zearalenone, gilt, reproduction, estrus, fetus
ARTIFICIAL REARING OF COLOSTRUM-DEPRIVED PIGLETS USING IRON CHELATORS: THE EFFECTS OF ORAL ADMINISTRATION OF EDDHA WITH AND WITHOUT BOVINE OR PORCINE IMMUNOGLOBULINS ON PIGLET PERFORMANCE AND IRON METABOLISM
Authors: DREW M. D. , BEVANDICK I. M. , OWEN B. D.
Published: March 2010

The iron chelator ethylene diamine-di-orthohydroxyphenyl acetic acid (EDDHA) was fed to 79 colostrum-deprived piglets with or without bovine or porcine serum immunoglobulins. Piglets that received bovine immunoglobulins from birth to day 14 had significantly lower survival rates, average daily weight gains and plasma immunoglobulin concentrations than piglets that received porcine immunoglobulins on the first day after birth. Piglets that received porcine immunoglobulins on day 1 followed by either bovine or porcine immunoglobulins on days 2–14 had significantly higher average daily gains than piglets that received no immunoglobulins on days 2–14. The addition of EDDHA to piglet's diets from birth to day 14 caused significant decreases in piglet average daily weight gains but had no effect on survival. EDDHA also caused significant reductions in packed cell volume and hemoglobin concentrations during the period it was included in the diet but these effects ceased when EDDHA was withdrawn. The effects of EDDHA on iron metabolism and excretion in the piglet were studied further using [59Fe]. Eight piglets were fed a commercial milk replacer containing either 0 or 37.5 mg kg−1 body weight d−1 of EDDHA. Piglets that received EDDHA had significantly longer plasma iron disappearance rates but did not significantly differ in hematocrits or plasma iron concentrations. Oral administration of EDDHA significantly increased the excretion of [59Fe] in the feces and urine and significantly reduced the incorporation of [59Fe] into red blood cells. There were no treatment differences in the distribution of [59Fe] in the livers or spleens of the piglets. Key words: EDDHA, immunoglobulins, piglet, artificial rearing, [59Fe]
HEAT PRODUCTION OF SKIP-A-DAY AND DAILY FED BROILER BREEDER PULLETS
Authors: BENNETT C. D. , LEESON S. , BAYLEY H. S.
Published: March 2010

Four broiler breeder pullets were reared on a skip-a-day feeding regimen according to breeder recommendations; another four pullets were fed daily the same average feed intake as the skip-a-day fed birds. At 15–17 wk of age the average and diurnal pattern of heat production and respiration quotients were determined using an open-circuit respiration calorimeter. Lower body weights of the skip-a-day fed birds may have been due to the day-to-day fluctuation in nutrient availability. Skip-a-day fed birds produced more heat per kilogram body mass. The diurnal pattern of heat production and respiration quotients indicated that skip-a-day fed birds were absorbing nutrients on the feed-day but were fasting for most of the off-feed day. Key words: Broiler breeder, feed restriction, heat production
THE EFFECTS OF DIETARY METHIONINE AND LYSINE ON BROILER CHICKEN PERFORMANCE AND BREAST MEAT YIELD
Authors: HICKLING D. , GUENTER W. , JACKSON M. E.
Published: March 2010

An experiment was conducted with 3840 male Ross × Arbor Acres broiler chicks to test the effects of increasing dietary methionine and lysine on performance and breast meat yield. Supplemental methionine and lysine were fed in a 2 × 4 factorial arrangement in both starter (0–3 wk) and finisher (3–6 wk) diets. Methionine was fed at levels of NRC and 112% NRC. Lysine was fed at levels of NRC and 106% NRC, 112% NRC and 118% NRC. Increasing dietary methionine increased weight gain (P < 0.01), feed efficiency (P < 0.01) from 3 to 6 wk, and breast meat yield (P < 0.01) at 6 wk. Increasing dietary lysine caused a curvilinear response in breast meat yield (P < 0.05). Key words: Broiler, lysine, methionine, breast meat
COMPARISON OF PHENOTYPIC VARIATION WITHIN PATERNAL HALF SIB FAMILIES FOR WEANING WEIGHT IN A PUREBRED AND A SYNTHETIC BEEF CATTLE POPULATION
Authors: LIU M. F. , MAKARECHIAN M.
Published: March 2010

Records of 1487 adjusted weaning weights expressed as deviations from year means in a multibreed Beef Synthetic and a purebred Hereford population raised and managed together under the same selection program from 1968 to 1978 were used to examine the behavior of the phenotypic variation within sire families in the two populations and to further test the conventional common error variance assumption imposed on a sire model. The results indicated that on the average there was no difference in the phenotypic variation within sire families between the purebred and the synthetic populations. Within-sire standard deviations in the two populations were also normally and similarly distributed. Within-sire variances were not heterogeneous. The results suggested that the conventional common error variance assumption imposed on a sire model would be a reasonable approximation applicable to the two populations of different origins. Key words: Beef cattle, variation among half-sibs, weaning weight
AVERAGE DAILY GAIN AND WATER INTAKE IN GROWING BEEF CALVES OFFERED SNOW AS A WATER SOURCE
Authors: DEGEN A. A. , YOUNG B. A.
Published: March 2010

Five calves were denied water for 112 d during winter but had access to snow as a water source (snow calves) and were compared with five calves that had continuous access to water (water calves). All calves were then given continuous access to water for a further 56 d. There was no significant difference between groups in water intake or average daily gain except at the beginning of the 56 d rewatering period when the snow calves drank more water per kg body mass than the water calves. Key words: Calves (weaned), average daily gain, snow, water intake, water influx, tritiated water
REPRODUCTIVE PERFORMANCE OF ROMANOV EWE LAMBS HAVING CONCEIVED AT THREE MONTHS OF AGE
Authors: FAHMY M. H.
Published: March 2010

Of 19 Romanov ewe lambs exposed to ram lambs up to 90 d of age, 11 lambed at 233 ± 2.8 d of age and 39.2 ± 0.74 kg body weight. They lambed 1.54 and weaned 1.18 lambs. Of these 11 ewes, 73% lambed again at 16 mo compared to 100% for less precocious ewes. Litter size was 2.50 and 3.25 at birth and 2.00 and 2.38 lambs at 70 d for the two groups, respectively. By 16 mo of age, both groups of ewes weighed about 53 kg, the ewes which lambed twice produced slightly more lambs; however, the weight of lambs produced at 70 d was similar in both groups (53.5 vs. 52.6 kg). Key words: Puberty, Romanov, reproductive performance
THE EFFECT OF ASSISTANCE AT CALVING, INJECTIONS OF RECOMBINANT BOVINE SOMATOTROPIN AND JUGULAR CATHETERIZATION ON SERUM CORTISOL AND ITS INFLUENCE ON THE GnRH-INDUCED LH RESPONSE IN POSTPARTUM DAIRY COWS
Authors: LEFEBVRE D. M. , GALLO G. F. , BLOCK E.
Published: March 2010

Serum cortisol levels were determined in 18 cows administered 25 mg d−1 of recombinant bovine somatotropin or a placebo following jugular vein catheterization on day 14 postpartum. Cows that received assistance at calving had lower (P < 0.01) serum cortisol concentration postpartum. Restraint and catheterization caused an elevation (P < 0.1) of cortisol levels. Treatment with rbST did not effect postpartum cortisol levels. LH response to exogenous GnRH was not affected by the postpartum Cortisol level. Key words: Cortisol, somatotropin, ganadotropin-releasing hormone, luteinizing hormone, dairy cow, stress
CARRYOVER EFFECTS OF SUPPLEMENTAL COPPER, MOLYBDENUM AND SULFUR IN GROWING CATTLE
Authors: BOILA R. J. , WITTENBERG K. M.
Published: March 2010

Supplemental Cu, Mo and S given over a 105-d feedlot trial with growing steers had no effect (P > 0.05) on growth or feed efficiency during a subsequent 49 d without supplemental Cu, Mo and S. Effects on Cu, Zn, Mn and Fe in liver obtained at slaughter were minor and within normal ranges for cattle. Key words: Cattle, growth, copper, molybdenum, sulfur
THE EFFECTS OF SHEARING AND RALGRO IMPLANTS ON FEEDLOT PERFORMANCE OF LAMBS DURING THE SUMMER
Authors: LANE S. F. , KEMP R. A.
Published: March 2010

To evaluate the effects of shearing and Ralgro® implants on the performance of fast-gaining feedlot lambs during the summer, 84 group-fed crossbred wether lambs (34.8 ± 1.8 kg) were shorn on day 0 of the feeding period (ES), shorn 3 wk later (LS), or left unshorn (NS), and either implanted with 12 mg Ralgro on day 0 (R) or not implanted (C). Lambs were blocked by initial weight. Heavy and light pens of lambs were shipped to market when the average weight within a pen was 52 kg after 40 and 55 d, respectively. Between days 0 and 40, mean average daily gain (ADG) of all lambs was 384 g and feed conversion was 4.38 kg dry matter kg−1 gain. During the first 40 d of the feeding period, shearing did not affect ADG (P > 0.05), but ES lambs had higher feed intake and poorer feed conversion than NS lambs (P < 0.05). Performance of the LS lambs was similar to the NS lambs prior to shearing, and similar to the ES lambs after shearing. A delay period between implantation and growth response was observed. Ralgro did not affect ADG between days 0 and 21 (P > 0.05) but improved ADG by 14.2% between days 21 and 40 (P < 0.01), giving an overall growth improvement of 6.5% between days 0 and 40 (P < 0.06). Ralgro had no effect on ADG after day 40. There were no interactions between the effects of shearing and Ralgro implantation on ADG (P > 0.05). Key words: Lambs, shearing, Ralgro, feedlot, summer
SOURCES OF VARIATION IN BEEF CATTLE WEANING WEIGHT
Authors: DINKEL C. A. , TUCKER W. L. , MARSHALL D. M.
Published: March 2010

Milk production, body condition, body weight and individual feed records for 196 2-yr-old heifers and their calves were used to evaluate sources of variation in weaning weight and its two major components, total energy consumption for the year and efficiency of energy use, defined as weaning weight divided by total energy for cow and calf. Four breed groups of cows including 29 Hereford, 73 Simmental × Hereford, 68 Angus × Hereford and 26 Tarentaise × Hereford were represented over the 6-yr period. Long-horn bulls sired the calves in all but the first 2 yr when Angus bulls were used. Sources of variation were evaluated by fixed model least squares and multiple regression analyses. The least squares analysis indicated the Hereford and Angus × Hereford differed only in level of condition both at calving and at weaning, with the Angus cross slightly fatter. The Simmental cross was highest in calving condition and equal to the Angus in weaning condition. The Simmental and Tarentaise crosses were similar and significantly different from the other breed groups in milk production and weaning weight of first calves. The Tarentaise cross was different from the other three groups in cow weight at weaning, cow efficiency and condition at weaning. The Tarentaise cross and Hereford group had lowest total cow and calf energy consumption, with Simmental cross highest and Angus cross intermediate. The Simmental cross achieved a high weaning weight through high energy consumption and slightly above average efficiency, while the Tarentaise group utilized high efficiency along with low energy consumption. The breed of dam by sex of calf interaction was significant for cow efficiency which has some implication for efficiency experiments that depend on group feeding. Standard partial regressions indicated that year followed by cow condition at weaning and milk production were leading sources of variation in weaning weight and efficiency. Year and cow weight at weaning were leading sources for total energy consumption. Cow weight at weaning was of least importance in determining weaning weight and efficiency. Key words: Weaning weight, cow efficiency, energy consumption, beef cattle
DEVELOPMENT OF DLS BREED OF SHEEP: GENETIC AND PHENOTYPIC PARAMETERS OF DATE OF LAMBING AND LITTER SIZE
Authors: FAHMY MOHAMED H.
Published: March 2010

Least square means, heritabilities, repeatabilities, genetic and phenotypic correlations of date of lambing and litter size in a population of DLS sheep selected for extended breeding season were estimated by different methods. Mean date of lambing for first, second and third parities was 20 Jan., 6 Jan., 31 Dec. and mean litter size was 1.20, 1.25 and 1.41 lambs, respectively. Heritabilities for date of lambing were 0.37 (sire component, 0.25 (sire and dam component), 0.52 (correlation between full sisters) and 0.17 (regression of daughter on dam). For litter size these methods gave the following estimates: 0.17, 0.14, 0.22 and 0.04, respectively. Repeatability estimates averaged 0.21 for date of lambing and 0.24 for litter size. Genetic correlation between the two traits was calculated at −0.38 (sire component), −0.25 (full sisters) and −0.07 (regression of daughter on dam) while the phenotypic correlation was estimated at −0.19 (P < 0.01). Key words: DLS sheep, heritability, repeatability, genetic correlation, phenotypic correlation, date of lambing, litter size
EFFECTS OF A 28-DAY SUSTAINED-RELEASE FORMULATION OF RECOMBINANT BOVINE SOMATOTROPIN (rbST) ADMINISTERED TO COWS OVER TWO CONSECUTIVE LACTATIONS
Authors: LÉONARD M. , GALLO M. , GALLO G. , BLOCK E.
Published: March 2010

Efficacy of a sustained-release formulation of recombinant bovine somatotropin (rbST) was evaluated for two consecutive lactations. In trial 1, 48 multiparous and 12 primiparous Holstein cows were allocated randomly by parity to four treatment groups receiving 0, 320, 640, or 960 mg rbST in a sustained-release formulation at 28-d intervals starting in early, mid-, or late lactation with the total treatment period being 252, 168, or 84 d for the three different starting periods, respectively. Fifteen cows receiving 640 or 960 mg rbST 28 d−1 in trial I received 640 mg rbST 28 d−1 in trial II for a full second lactation and were paired with cows receiving a placebo and which were never administered rbST. Cows were fed total mixed rations ad libitum and milked twice daily. Response in milk and milk component yield was positive and very consistent for multiparous cows between trials. Primiparous cows responded in both lactations with the same numerical magnitude as multiparous cows but with higher variability. No adverse effect of treatment on final body condition score and achievement of proper condition for a subsequent lactation was found because treated cows had lower condition scores for a longer period of time but regained body condition at a faster rate in late lactation. No effect of treatment was observed on health parameters in either lactation. Trends towards longer days open and more breedings per conception were apparent for both lactations. Key words: Somatotropin, milk production, health, dairy cows, primiparous cows
INFLUENCE OF GROWTH HORMONE-RELEASING FACTOR AND (OR) THYROTROPIN-RELEASING FACTOR ON SOW BLOOD COMPONENTS, MILK COMPOSITION AND PIGLET PERFORMANCE
Authors: DUBREUIL P. , MORISSET J. , PELLETIER G. , PETITCLERC D. , LAPIERRE H. , COUTURE Y. , GAUDREAU P. , BRAZEAU P.
Published: March 2010

Two experiments were conducted using a 2 × 2 factorial design to determine the effect of porcine growth hormone-releasing factor (pGRF(1–29) NH2) and (or) thyrotropin-releasing factor (TRF) on the endocrine and metabolic status of sows as well as production performance during the lactation period. In exp. 1, sows were assigned to the following treatments: control (vehicle 3 mL, n = 6); pGRF(1–29)NH2 (20 μg kg−1, n = 7);TRF(1 μ kg−1, n = 7); pGRF + TRF (20 and 1 μg kg−1, respectively, n = 6). In the second experiment, 24 sows were equally distributed to the same treatments as in exp. 1 but the dose of TRF was increased to 9 μg kg−1. During lactation (28 d), releasing factors were administered subcutaneously at 10:00 h and 16:00 h from days 5 to 25, inclusively. Serum growth hormone (GH), thyroxine (T4) and prolactin (PRL) concentrations were assayed on days 5, 15 and 25. In both experiments, TRF stimulated T4 release on all sampling days. However, with advancing lactation and/or days of injection, basal and TRF-stimulated T4 levels decreased (P < 0.05). In the second experiment, GRF increased GH release on each sampling day while saline and TRF had no effect (P > 0.05). The GH response to GRF was higher (P < 0.05) on days 15 and 25 compared to day 5 and higher on day 25 compared to day 15. Also, in both experiments, TRF stimulated PRL release on all sampling days. With advancing lactation and/or days of injection, basal and TRF stimulated PRL release decreased (P < 0.05). In exp. 1, serum creatinine (P < 0.01) and blood urea nitrogen (P = 0.06) concentrations were decreased by GRF treatment while TRF treatment increased (P < 0.01) blood glucose and decreased (P = 0.07) serum cholesterol concentrations. In both experiments, milk yield, fat, protein and lactose contents were unaffected (P > 0.05). Piglet body weight gain and sow weight loss were not affected (P < 0.05) by treatments. Results showed that GRF increases the release of GH while TRF stimulates T4 and PRL release during lactation. However, none of these endocrine modifications influenced production performance. Key words: GRF, TRF, hormone, milk, sow, piglet
THE USE OF BLOOD SERUM COMPONENTS IN THE IDENTIFICATION OF STRESS-SUSCEPTIBLE AND CARRIER PIGS
Authors: SCHAEFER A. L. , DOORNENBAL H. , SATHER A. P. , TONG A. K. W. , JONES S. D. M. , MURRAY A. C.
Published: March 2010

A total of 284 pigs representing three genotypes were used to study the cause(s) of PSE musculature and possible means of detection of carriers of the halothane gene for stress susceptibility. The three genotypes included a homozygous halothane-sensitive line (H+), a homozygous halothane-negative line (H−) and a genetic carrier line (crossbreeds) from crosses between H+ and H− lines. A variety of blood components were determined in blood collected either from indwelling ear vein catheters on unrestrained pigs, from pigs during a halothane test or from conscious restrained pigs. Differences in levels of cortisol (P = 0.0003), creatinine (P = 0.0001), aspartate aminotransferase (AST, P = 0.0001) and lactate dehydrogenase (P = 0.0001) were highly significant between H+ and H− lines, with crossbreeds showing intermediate levels, except for AST where H− and crossbred animals had similar levels. In addition, red blood cell counts (P = 0.014) and serum protein levels (P = 0.008) were higher, and inorganic phosphorous (Pi) levels (P = 0.019) lower in H+ compared to H− and crossbred animals. Based on the results of this study, differences in the circulating levels of these metabolites, hormones or enzymes among genotypes would enable the discriminant identification of virtually all the halothane-positive pigs as well as up to 84% of the carrier animals. This approach theoretically could have a significant impact on the removal of pigs causing PSE pork.
THE INFLUENCE OF BICARBONATE BUFFERS ON MILK PRODUCTION AND ACID-BASE BALANCE IN LACTATING DAIRY COWS
Authors: McKINNON J. J. , CHRISTENSEN D. A. , LAARVELD B.
Published: March 2010

Two 4 × 4 Latin square feeding trials were conducted to investigate the influence of 0.75% sodium bicarbonate (NaHCO3), 0.75% potassium bicarbonate (KHCO3) and 0.66% ammonium chloride (NH4Cl) on production and acid-base parameters of dairy cows. Buffer supplementation did not improve feed intake or milk production compared to the control ration of 50% concentrate, 50% barley silage (DM basis). Apparent digestibilities of dry matter, acid detergent fiber and crude protein were not influenced by treatment. Buffer supplementation resulted in an increase in milk fat and total solids content in trial 2 but not in trial 1. In comparison to the two buffered rations, NH4Cl induced a mild form of acidosis as evidenced from reduced (P < 0.05) blood pH, HCO3, BE and urine pH values in trial 1 and blood HCO3 and urine pH in trial 2. In addition, DM and concentrate intake were reduced in trial 2 with NH4Cl supplementation. Treatment did not affect the molar proportions of the major rumen volatile fatty acids (VFA). It is concluded that milk fat production did not respond as expected to buffer supplementation due to a failure to influence the pattern of rumen VFA production. The control ration did not stress the acid-base homeostasis of the animal. Consequently, buffer supplementation did not lead to any improvement in systemic acid-base status. Key words: Dairy cattle, milk production, potassium and sodium bicarbonate, ammonium chloride, acid-base balance
COMPARISON OF COPPER SULFATE AND COPPER PROTEINATE AS COPPER SOURCES FOR COPPER-DEPLETED STEERS FED HIGH MOLYBDENUM DIETS
Authors: WITTENBERG K. M. , BOILA R. J. , SHARIFF M. A.
Published: March 2010

Copper (Cu) depleted steers were used to compare copper sulfate and copper proteinate as Cu sources for cattle consuming high molybdenum diets. Two experiments utilizing corn silage and barley concentrate diets with 10 mg added Mo kg−1 DM were undertaken. Experiment A was a 105-d study in which an 83:17 ratio of silage to concentrate was fed, whereas, experiment B was an 84-d study comparing the same Cu treatments for cattle fed a 26:74 (Low) or a 64:36 (High) ratio of silage to concentrate. Cu treatments for both experiments were: no supplemental Cu (0Cu); a dietary supplement of 10 mg Cu kg−1 DM added as copper sulfate (CuSO); and a dietary supplement of 10 mg Cu kg−1 DM added as copper proteinate (CuPro). Both Cu supplements improved (P < 0.05) concentrations of Cu in plasma for both experiments and improved (P < 0.05) concentration of Cu in liver for experiment B. Copper supplementation (P < 0.05) reduced plasma Mo concentrations in experiment A relative to animals receiving no supplemental Cu. Both Cu sources resulted in reduced rumen fluid soluble Mo concentrations. Steers in experiment A had lower initial liver and plasma Cu concentrations than was observed for experiment B. Average daily gains for steers consuming CuPro were 16.8% greater (P < 0.05) than for 0Cu with CuSO being intermediate for experiment A. Results indicate that the bioavailability of Cu from Cu proteinate is similar to that of copper sulfate in-Cu depleted steers consuming diets containing excess Mo. Key words: Cattle, copper sulfate, copper proteinate, copper, molybdenum
THE EFFECT OF RACTOPAMINE ON PERFORMANCE, CARCASS COMPOSITION AND MEAT QUALITY OF FINISHING PIGS
Authors: AALHUS J. L. , JONES S. D. M. , SCHAEFER A. L. , TONG A. K. W. , ROBERTSON W. M. , MURRAY A. C. , MERRILL J. K.
Published: March 2010

One hundred and twenty-eight purebred Lacombe pigs (equal numbers of barrows and gilts) were assigned to one of four treatments at 64 kg and fed a commercial grower-finisher diet ad libitum to which ractopamine (RAC) was incorporated (0 mg kg−1, 10 mg kg−1, 15 mg kg−1, or 20 mg kg−1). Pigs were slaughtered at 100 kg. RAC had no significant effect on growth rate, feed intake, feed efficiency or on days on feed. Predicted lean content obtained by the Hennessy Grade Probe regression equation (from fat and muscle depth) increased by 0.3%, 0.7% and 0.9%, respectively (P = 0.009) as RAC was added to the diet at 10, 15 and 20 mg kg−. Dissected lean yield, as measured by separation of four primal cuts into lean, bone and fat depots, increased by 1.9%, 2.3% and 3.2%, respectively (P = 0.001) for the same levels of RAC. Greatest muscle increases were found in the ham (10.7%). There was a clear anterior to posterior gradient for fat reduction in both the subcutaneous (Picnic 13.4%, Butt 13.5%, Loin 10.7%, Ham 8.2%) and intermuscular (Picnic 16.2%, Butt 13.7%, Loin 8.8%, Ham 5.3%) fat depots. RAC increased intramuscular fat content (P = 0.009), expressible juice (P = 0.001), shear value (P = 0.011) and decreased fat hardness (P = 0.026). Based on the results of this study, RAC would be expected to have minor effects on swine growth performance and meat quality, but would increase the lean content of the carcass. Key words: Swine, ractopamine, carcass composition, meat quality
AN ALTERNATIVE HOUSING SYSTEM FOR SOWS
Authors: MORRIS J. R. , HURNIK J. F.
Published: March 2010

A group housing system for sows, the Hurnik-Morris (H-M) System, is described which addresses several of the serious animal welfare limitations of existing housing methods. The H-M System permits socially coordinated eating and resting, controlled and socially undisturbed feed consumption, physical exercise and regular exposure to boars. Sows adjusted relatively rapidly to the H-M System, indicating that its design concurs with their perceptual and learning capabilities. Key words: Swine, housing, behavior, welfare