bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a mobile, open-circuit indirect calorimetry system
Authors: Kelly J. M. , Kerrigan B. , Milligan L. P. , McBride B. W.
Published: March 2010

A system for the rapid determination of O2 consumption, CO2 production and subsequent indirect estimation of energy metabolism of ruminants has been updated and validated. The accurate determination of gas temperature, relative humidity, absolute pressure and flow is important to the overall use of the system. Analogue outputs from the specific analyzers were multiplexed and then routed to a data acquisition system with appropriate software control. Subsequent data processing included modification to fit LOTUS 1-2-3 files. The analyzers were calibrated with standard test gases for the gas meters. In an experimental confirmation trial, eight sheep were fed at maintenance (M) or 2× maintenance (2M) or fasted 48 h after each level of intake (MF and 2MF, respectively) and subsequent energy metabolism was determined. Oxygen consumption (mL min−1), metabolic rate (W) and CO2 production (mL min−1) were greater (P < 0.05) for animals fed 2M (111.2, 379.5 and 101.9, respectively) than for those fed M (85.4, 291.2 and 86.1, respectively). Maintenance values were, in turn, also higher (P < 0.05) than those for either MF (56.7, 193.4 and 48.0, respectively) or 2MF (54.6, 186.4 and 46.3, respectively). M sheep had a higher respiratory quotient (1.03) (P < 0.05) than either MF sheep (0.86) or 2MF sheep (0.89), with 2M sheep being intermediate (0.95). There were no differences (P > 0.05) between the two fasted states for all parameters. Results from the confirmation experiment agree with previously published work and were consistent with those from similar systems. Key words: Indirect calorimetry, oxygen consumption, sheep
The effect of zeranol implants on growth and pregnancy loss in beef heifers
Authors: King B. D. , Kirkwood R. N. , Guenther C. L. , Cohen R. D. H. , Bo G. A. , Mapletoft R. J.
Published: March 2010

Live weight, average daily gain (ADG) and reproductive performance were compared between heifers implanted with zeranol at birth, 100 and 200 d of age (n = 54) and those not implanted (n = 50). Zeranol implantation resulted in increased (P < 0.05) ADG from birth to weaning, weaning weight, ADG from weaning to breeding, breeding weight and calving weight but did not affect (P > 0.05) calf birth weights, incidence of dystocia, calf survival or gestation lengths. Zeranol implants did not affect (P > 0.05) the incidence or magnitude of the pre-ovulatory LH surge or the number of heifers that ovulated between 48 and 168 h after cloprostenol injection. Pregnancy rate 42 d after bull entry did not differ between the two groups (P > 0.10), tended toward a difference at 72 d (P < 0.10), and was different at 133 d (P < 0.05), with implanted heifers having a lower pregnancy rate than non-implanted heifers. Between day 72 and day 133 after bull entry there was a 10% embryonic or fetal mortality rate in zeranol-implanted heifers, which differed from the 0% loss in non-implanted heifers (P < 0.05). We conclude that serial implants of zeranol from birth reduced the pregnancy rate in heifers and that this effect was due to early fetal loss. Key words: Zeranol, embryonic/fetal mortality, bovine, pregnancy rate, ultrasonography
Comparative yield and feeding value of barley, oat and triticale silages
Authors: McCartney D. H. , Vaage A. S.
Published: March 2010

The yield and feeding value of barley (Hordeum vulgare 'Johnson'), oat (Avena sativa 'Calibre') and triticale(Triticosecale 'Carmen') silages were compared in a field study, a heifer growth trial (119 d in length, with four pens of eight Charolais cross heifers (average body weight 300 kg) per treatment), and a sheep digestibility trial (total fecal collection with eight sheep per treatment). The swathed and chopped plant material was ensiled in stack silos covered with plastic. Yields of dry matter (DM) and crude protein (CP) did not differ significantly (P > 0.05) among species. At harvest, oat and triticale had greater acid detergent fiber (ADF) levels than barley. After ensiling, triticale alone had greater neutral detergent fiber, ADF and acid detergent insoluble nitrogen levels than the other silages. The three silages did not otherwise differ in chemical composition. Heifer intakes of barley (6.06 kg d−1) and oat (5.70 kg d−1) silage DM were similar, and greater than for triticale (4.86 kg d−1). Average daily gain was greatest with barley (0.65 kg d−1), intermediate with oat (0.57 kg d−1) and least with triticale (0.49 kg d−1). Intake of silage DM by the sheep was greatest with barley silage (741 g d−1), intermediate with oat (617 g d−1) and least with triticale (434 g d−1), which appeared less palatable than the other silages. Dry matter and CP digestibilities were greatest for barley silage (64.2 and 71.6%, versus 58.3. and 61.1% for oat, and 58.8 and 65.4% for triticale, respectively). Oat silage had the lowest fiber digestibility. Sheep given triticale silage had lower rumen fluid volatile fatty acid concentrations, apparently due to low DM intake. Oat silage gave a greater molar proportion of acetate, a lower proportion of propionate, and a higher acetate to propionate ratio than either barley or triticale. Triticale silage produced a greater molar proportion of acetate and a lower proportion of butyrate than barley silage. Based on animal performance, it was concluded that barley silage was the preferred of the three cereal silages for growing cattle. Triticale produced a less acceptable silage due to poor palatability and low DM intake. Key words: Cattle, sheep, cereal silage, forage quality, digestibility
Effect of postpartum bull exposure on calving interval of first-calf heifers bred by natural service
Authors: Larson C. L. , Miller H. L. , Goehring T. B.
Published: March 2010

Ninety-four first calf heifers were utilized to evaluate the effect of bull exposure on the calving interval. Heifers were alternately assigned after calving to a pasture containing epididymectomized bulls for 60 d or were not exposed. Thirty-five days prior to the breeding season the bulls were removed and the two groups co-mingled. Bull-exposed heifers had a 9-d increase in calving interval and a 7-d delay in average calving date compared to unexposed heifers (P < 0.05). Bull exposure early postpartum did not shorten the calving interval of heifers in condition score of 5 or better at calving and bred by natural service under the conditions of this study. Key words: Bull exposure, first-calf heifers, reproduction, calving interval, postpartum
The effects of fat thickness and degree of marbling on pork colour and structure
Authors: Jones S. D. M. , Tong A. K. W. , Dyck R. , Campbell C.
Published: March 2010

Fat thickness (3rd–4th last rib) was weakly correlated with subjective pork structure score (R2 = 1.0%) and marbling score (R2 = 1.6%) in 399 boneless pork backs sampled from commercial processing plants. Pork colour and structure scores (R2 = 5.9 and 11.1%) were more highly correlated with marbling score than carcass fat and muscle depths (R2 = < 2.0%). Pork backs that had structure scores of 1 and 2 (extreme to slight soft and exudative pork) tended to have low amounts of marbling (traces or less). A second trial with 311 pork backs also indicated that higher marbling scores were associated with lower frequencies of pale, soft and exudative pork. Key words: Pork quality, marbling, PSE
Effects of maceration at mowing on digestibility and ruminal fermentation of timothy hay in steers
Authors: Chiquette J. , Savoie P. , Lirette A.
Published: March 2010

Eight ruminally fistulated steers (711 kg ± 72 kg) were used in a crossover experimental design to study the nutritional effects of macerating timothy grass (M) over the conventional conditioning process (C). Maceration was applied at mowing by conditioning the freshly cut forage through eight high-speed metallic grinding rolls with a shredding effect on leaves and stems. Animals were fed an all forage diet consisting of M or C. Feces were collected over a period of 6 d for total digestibility determination. On day 7 of each experimental period, ruminal fluid was sampled at 0, 1, 2, 4, 8 and 12 h after meals. On days 9–11, nylon bags were incubated in the rumen of each steer for 4, 8, 12, 24 and 48 h in order to determine forage dry matter (DM) degradation at the ruminal level. Maceration reduced the field drying time to reach baling moisture by 50% under Southeast Canadian climatic conditions. Results of forage digestibility at the ruminal level showed that the rate of forage DM disappearance was greater (P < 0.001) for M than for C. This greater ruminal digestibility of M was associated with numerically although not statistically greater ruminal concentrations of acetate, propionate and butyrate at all sampling times in steers fed M. However, butyrate concentration was higher (P < 0.05) in M fed animals than in C fed animals, at the 4 h sampling. Although M was better digested at the ruminal level, total digestibility of DM, organic matter, ADF and NDF was slightly less for M than for C (P < 0.05). Total digestibility of nitrogen was similar for both treatments. An increased passage rate of M might explain its decreased total digestibility. This last assumption still needs to be verified as well as the impact of this small decrease in digestibility on animal production. Key words: Maceration, digestibility, ruminal fermentation, steer, forage, grass
Effects of recombinant porcine somatotropin (rpST) on joint cartilage and axial bones in growing and finishing pigs
Authors: He P. , Aherne F. X. , Nam D. S. , Nakano T. , Schaefer A. L. , Thompson J. R.
Published: March 2010

Seventy-two gilts (PIC, Cambourough) weighing 20 kg were allocated to four pens, each with two electronic feeders. After a 20-d conditioning period, eight pigs (two pigs/pen) were slaughtered for initial carcass measurements. The remaining pigs in each pen, at an average liveweight of 33.0 ± 2.49 kg (mean ± SD), were randomly assigned to three treatments: daily saline injection (control), daily injection of recombinant porcine somatotropin (rpST) (100 μg kg−1 liveweight) and a treatment group in which rpST injected pigs were switched to a saline injection at approximately 63 kg liveweight (withdrawal). Eight control and eight rpST-treated pigs, two from each pen were slaughtered at an average liveweight of 62.8 ± 3.72 kg, and the remaining pigs were slaughtered at 100.3 ± 5.51 kg. Daily injection of rpST increased the average concentration of plasma somatotropin but did not increase the width of distal ulna epiphysis. Vertebrae and ribs of pigs injected with rpST from 33.0 to 100.3 kg liveweight showed a higher water content (P < 0.01), a lower ash content of moisture-free bone (P < 0.05), and lower dry matter (P < 0.01) and ash (P < 0.001) densities than those of control pigs. Withdrawal of rpST injection at 62.8 kg liveweight abolished the effect of rpST on all bone properties except for the ash density. Injection of pigs with rpST from 33.0 to 100.3 kg resulted in higher (P < 0.05) humeral condyle lesion score and decreased average concentrations of uronic acid (P < 0.05) and hydroxyproline (P < 0.005) in cartilage from both distal humeral and femoral condyles but had no significant effect on the ratio of uronic acid to hydroxyproline compared with control animals. Withdrawal of rpST treatment at 62.8 kg diminished the effect of rpST on cartilage soundness and uronic acid and hydroxyproline concentrations of the joint cartilage. The long-term use of rpST reduced chondrocyte metabolism, which may indirectly reduce compressive and tensile strength of cartilage and increase susceptibility to mechanical stress, leading to osteochondrosis. Key words: Osteochondrosis, growth rate, recombinant porcine somatotropin, bones, pigs
Recombinant porcine somatotropin effects on sexual development and metabolic status of gilts
Authors: Beltranena E. , Aherne F. X. , Foxcroft G. R. , Schaefer A. L.
Published: March 2010

Prepubertal Yorkshire gilts (61.7 ± SD 3.7 kg) served as untreated controls (n = 8), were injected daily (at 15:00) for 28 d with 2 mg of porcine somatotropin (pST; n = 8), or were implanted with a prolonged-release (2 mg d−1 for 28 d) pST implant (n = 7). Gilts had ad libitum access to feed except during an overnight fast before blood sampling (06:00 to 22:00 h) on day 23 or 24. Feeding on day 23 or 24 resumed at 09:00 h and injected gilts received pST at 15:05 h. Gilts were slaughtered on day 28. Endogenous episodic ST secretion in both injected and implanted gilts was suppressed, but basal plasma ST in implanted gilts was elevated. Plasma insulin was elevated in response to pST injection and in implanted gilts postprandially, compared with controls. Plasma insulin-like growth factor I (IGF-I) was elevated in both injected and implanted gilts preprandially and postinjection. Plasma nonesterified fatty acids and creatinine were similar among groups. Urea nitrogen declined after feeding, and this decline was greater in injected than in implanted or control gilts. Basal episodic luteinizing-hormone (LH) secretion, reproductive-tract weight, follicular volume, and plasma and follicular-fluid estradiol-17β were similar among groups. However, follicular-fluid IGF-I concentrations were greater in injected and implanted, than control gilts. We conclude that pST administration (2 mg d−1) for 28 d significantly affected the ST–insulin–IGF–1 axis, but it did not affect LH secretion or reproductive-tract development. The pST-induced increase in follicular-fluid IGF–I may be of physiological significance to continued follicular development. Key words: Gilts, somatotropin, reproduction, metabolic status
Effect of mid-luteal phase progesterone levels on the first wave dominant follicle in cattle
Authors: Taylor C. , Rajamahendran R.
Published: March 2010

A wave-like-pattern of follicular growth and regression during the luteal phase has been described in the bovine. The factors responsible for inducing the onset of regression of nonovulatory dominant follicles are unknown. The present study was designed to examine the effect of progesterone (P4) administration early in the estrous cycle on the first wave dominant follicle. Nine heifers were administered P4 on day 3 (200 mg), day 4 (100 mg) and day 5 (50 mg) of the estrous cycle (Day 0 = day of estrus) and seven heifers received vehicle to serve as controls. All heifers received a luteolytic dose of prostaglandin F2α (PGF2α) on day 7. Follicular dynamics were monitored by daily ultrasonography. All seven control heifers ovulated the first wave dominant follicle. In four P4 treated heifers, the first wave dominant follicle regressed prior to PGF2α administration and a dominant follicle from the second pool of follicles ovulated. The remaining five P4 treated heifers ovulated the first wave dominant follicle. However, in these heifers the growth of the first wave dominant follicle was slower (0.65 ± 0.13 mm day−1 between days 3 to 7 for treated vs 1.46 ± 0.23 mm day−1 for control; P < 0.05) and estrus and ovulation were delayed compared to controls (3.8 ± 0.3 vs 2.4 ± 0.2 and 5.2 ± 0.4 vs 3.9 ± 0.2 days after PGF2α, respectively; P < 0.05). The results indicate that P4 administered early in the estrous cycle to mimic the mid luteal phase levels alters follicular dynamics and is capable of inducing premature regression of the first wave dominant follicle. Key words: Progesterone, dominant follicle, cattle, atresia, ovulation
Productivity of farmed wapiti in Alberta
Authors: Friedel B. A. , Hudson R. J.
Published: March 2010

Calving and weaning rates of 1084 wapiti hinds (females) were collected in the 1990 season by an on-farm survey of 50 producers in Alberta, to determine the reproductive performance of farmed wapiti. A calving rate of 81 and 96% for 2-yr-old and adult hinds, respectively, gave a provincial herd average of 93%. Weaning rates of 73% for 2-yr-old and 91% for adult hinds resulted in an 88% weaning rate overall. One set of triplets and three sets of twins gave a multiple birth ratio of one in 271 calvings. Overall calf mortality was 5.2% in the survey, with a trend (P = 0.07) for 2-yr olds to experience higher calf mortalities (9.5%) than adult hinds (4.4%). Dystocia accounted for two-thirds of the total calf mortalities reported in the survey. Although 2-yr olds calved later than adult hinds (11 June vs. 6 June), hind pre-rut weight influenced calving dates. Male calves were heavier (94 vs. 85 kg, (P = 0.0001) than female calves at 100 d due to their faster growth rate (753 vs. 686 g d−1, P = 0.0001). Growth rate and consequently weaning weights were positively influenced by hind pre-rut weight. The mean length of the breeding season was 111 d with producers exposing an average of 21 hinds per breeding stag on 1.2 ha of pasture per wapiti yr−1. The calf production ratio at 200 d was 52.5 kg calf per 100 kg hind for individual females weaning a calf, and was 46.2 kg calf per 100 kg of hind exposed on a herd basis. Pre-rut weaning was associated with improved calving (3.3%), weaning rates (2.6% in adult hinds and 13.4% in young hinds), decreased calf mortality (3.2%), advanced calving dates (5 d), and improved growth to 200 d (8%). Key words: Game farming, wapiti, reproduction, calving, weaning, growth
Effect of dietary fibre level on amino acid digestibility in young pigs
Authors: Li S. , Sauer W. C. , Hardin R. T.
Published: March 2010

Studies were carried out with 12 pigs (Yorkshire × Landrace) to determine the effect of dietary fibre level on amino acid digestibility. The pigs were weaned at 21 d of age and fitted with a simple T-cannula at the distal ileum at 23 or 24 d of age. The pigs were fed four isonitrogenous corn starch-based soybean meal diets (22.5 % crude protein) containing 4.3, 7.3, 10.3 and 13.3% Solkafloc according to a balanced two-period change-over design. The pigs were fed four times daily, equal amounts, at 6-h intervals. The diets were supplied at a rate of 5% of the average body weight which was determined at the initiation of the first (8.8 kg) and second (11.7 kg) experimental period. Each experimental period comprised 10 d. Feces were collected for 48 h on days 6 and 7 and ileal digesta for 24 h during days 8, 9 and 10. Chromic oxide was used as digestibility marker. The dietary inclusion of Solkafloc, up to 13.3 %, did not affect (P > 0.05) the apparent ileal as well as the fecal digestibilities of crude protein and amino acids. In conclusion, starter pigs can tolerate up to 13.3% Solkafloc, equivalent to 16.8% neutral-detergent fibre, in corn starch-based soybean meal diets without a depression in amino acid digestibility. Key words: Young pigs, fibre, amino acids, digestibility
Effects of top covering and ground base on round bale hay quality over winter
Authors: Hand R. K. , Winchell W. , Lopetinsky K. , Goonewardene L. A. , Yaremcio B. , Slack W. L.
Published: March 2010

The effect of top treatments no-cover (NC), tallow (TL) and tarp (TR) and bottom treatments gravel (G) and soil (S) on dry matter (DM) and quality changes over 290 d were studied in round hay bales. Total DM losses in TR (1.3%) were significantly (P < 0.01) lower than NC (5.7%) and TL (10.2%). Bales stored on G had less DM loss at the bottom of the bale (1%) compared to S (1.3%). Tallow mixture was not effective in protecting bales stored outside. Key words: Tallow, tarp, soil, gravel, hay, nutrients, round bales
Relative economic values for Canadian beef production using specialized sire and dam lines
Authors: MacNeil M. D. , Newman S. , Enns R. M. , Stewart-Smith J.
Published: March 2010

A deterministic herd-level model was developed to simulate profit (income minus expense) from 100 beef cows in western Canada. The cow-herd was composed of three synthetic strains (M1, M2 and M4) mated in rotation and at equilibrium with respect to age and genotype. Two synthetic "terminal sire" strains (M3 and TX) were also simulated. Heifers were mated with M3 to minimize dystocia when calving at 2 yr of age. Cows greater than 5 yr of age were bred to TX. Baseline economic and biological data were obtained from Beefbooster breeders. Endpoints considered were weaned calves, backgrounded steer and heifer calves, finished steers and heifers, and carcass weight and grade. Variable costs included feed consumed by the cow-herd (76% of variable costs to weaning), non-feed items to weaning, and feed consumed by market progeny after weaning. Relative economic values (âi) were changes in profit ensuing from unit changes of the baseline strain specific biological characteristics. Elements of â were economic values for: cow weight, kg; male and female fertility, %; calf survival, %; direct and maternal effects on weaning weight, %; rates of gain on backgrounding and finishing rations, kg/d; feed conversion, dressing percent, % A grade and carcass cutability, %. For M1, M2 and M4 â was: [− 0.11 0.87 1.31 0.90 0.06 0.06 1.90 16.27 − 0.61 2.78 0.18 4.81]; for M3 â was: [0.00 0.38 0.00 0.28 0.03 0.00 0.95 4.74 − 0.21 0.92 0.06 1.67]; and for TX â was: [0.00 1.90 0.00 0.89 0.06 0.00 1.32 16.07 − 0.64 2.85 0.19 5.10] at the carcass endpoint. Direct and maternal weaning weight had greater âi at weaning than at later endpoints and âi for feed conversion increased in magnitude as time on feed increased. Key words: Beef cattle, selection program, breeding objective
Bloat in cattle fed alfalfa selected for a low initial rate of digestion
Authors: Hall J. W. , Majak W. , Stout D. G. , Cheng K.-J. , Goplen B. P. , Howarth R. E.
Published: March 2010

Investigations of legume species which do and do not cause bloat suggested that a bloat-safe alfalfa (Medicago sativa L.) might be produced by reducing its initial rate of digestion. This study compared a third cycle alfalfa synthetic selected for a low initial rate of digestion (LIRD) with a control cultivar (Beaver). The occurrence of bloat was not significantly lower when cattle were fed cycle 3 LIRD than when fed Beaver in three grazing trials or in two of three feedlot trials. The deviation of the results in the third trial could not be explained by differences in dry matter or protein content. When grown under irrigation, the 4 h dry matter disappearance (DMD) of cycle 3 LIRD was 89% to 96% of that for Beaver. This reduction was much less than has been hypothesized to prevent bloat. Without irrigation the 4 h DMD of both cultivars were reduced by 1–3% while cycle 3 LIRD continued to have a lower DMD than Beaver. LIRD may provide some protection against bloat on dry rangelands though the response may be variable in years when moisture is well supplied. Studies with a fourth cycle LIRD selection will investigate this further. Key words: Legumes, Medicago sativa L., nylon bag, digestion
Effects of exogenous steroid hormones on the dominant follicle maintained by a Norgestomet implant in heifers
Authors: Rajamahendran R. , Manikkam M.
Published: March 2010

The maintenance of the dominant follicle during the follicular phase by a 9-d Norgestomet implant was used to study the effects of progesterone (P4), estradiol-17β (E2) and testosterone (T) on follicular turnover in heifers. From day 4 of Norgestomet treatment, heifers (n = 16) were injected daily for 4 d with corn oil (control), 150 mg P4, 10 mg E2 or 200 mg T (n = 4 per treatment). Follicular changes were monitored daily by ultrasonography. Plasma steroids and serum LH were measured by validated radioimmunoassays. In control heifers, dominant follicles were maintained during implantation and ovulated after implant removal. In both P4- and T-treated heifers, dominant follicles began to regress during the implant period and the dominant follicle from a new wave of follicles ovulated. In E2-treated heifers, dominant follicles regressed (3/4) and dominant follicles from the next wave ovulated. The dominant follicle became cystic in the fourth E2-treated heifer. Mean serum LH levels were suppressed (P < 0.01) from 0.55 ± 0.01 ng mL−1 (mean ± SEM) in control to 0.21 ± 0.02, 0.19 ± 0.02 and 0.43 ± 0.02 in P4-, E2- and T-treated heifers, respectively. The number of LH pulses in 8 h was reduced (P < 0.01) from 6.25 ± 0.75 in control to 2.00 ± 1.00 and 4.66 ± 0.35 in P4- and E2-treated heifers but not in T-treated heifers (6.33 ± 1.44). LH pulse amplitude (ng mL−1) was also suppressed (P < 0.01) in P4-treated (0.10 ± 0.04) and E2-treated (0.09 ± 0.02) heifers when compared with control heifers (0.41 ± 0.04) but not in T-treated heifers (0.42 ± 0.17). Exogenous P4 and E2 caused regression of the Norgestomet-maintained dominant follicle, and this effect was associated with altered serum LH profile. Injection of T caused atresia of the dominant follicle without altering the LH profile. Key words: Dominant follicle, atresia, heifers, steroids, LH, ultrasound, E2, estradiol-17β; P4, progesterone; T, testosterone
Effect of salinomycin on fermentation and nitrogen metabolism in the artificial rumen
Authors: McAllister T. A. , Moustafa S. M. S. , Cheng K.-J. , Newbold C. J. , McKain N. , Wallace R. J.
Published: March 2010

Peptidase activities against Ala3, Ala4 and Phe3 were increased (P < 0.05) by salinomycin, whereas activities against Ala5 and Phe4 were unchanged and that against Gly-Arg-MNA was decreased (P < 0.05). In the presence of salinomycin, the main products of peptide hydrolysis were single amino acids, whereas dipeptides were formed in samples from control vessels. Key words: Ionophores, salinomycin, peptidases, peptide, Rusitec
The potential of isobutyraldehyde monourea (propanal, 2-methyl-monourea) as a nonprotein nitrogen source for ruminant animals
Authors: Mathison G. W. , Soofi-Siawash R. , Worsley M.
Published: March 2010

Experiments were earned out with sheep and in vitro to evaluate isobutyraldehyde monourea (IBMU; propanal-2-methyl-monourea) as a slow-release nitrogen source for ruminant animals. Examination of the compound for carbon, hydrogen, and nitrogen composition and infrared, NMR and mass spectral analyses indicated that IBMU was present in significant amounts. Ten sheep were randomly assigned to diets containing bromegrass hay and corn grain and the following nitrogen supplementation treatments: (1) control, (2) urea, (3) soybean meal, (4) canola meal and (5) IBMU, with the protein supplements providing approximately 25% of the nitrogen intake. Similar treatments were also prepared and evaluated in vitro, with the exception that wheat straw rather than bromegrass hay was used in the incubation. The digestibility of nitrogen in the ration containing IBMU was higher (P < 0.05) than its digestibility in the other rations when measurements were conducted with sheep over three 14-d periods. No differences in dry matter (DM) or energy digestibility were detected between the different treatments. The digestible energy content of IBMU was estimated to be greater than 21 MJ kg−1. The digestibilities of DM in vitro after 2, 4, 8, 12, 24, 48 and 72 h of incubation were not influenced by the presence of IBMU. No influence of nitrogen supplementation on nitrogen balance was observed, probably because of the high protein content of the control ration (10.6%). IBMU exhibited the characteristics of an ideal slow-release nonprotein nitrogen supplement, since concentrations of rumen ammonia nitrogen did not vary from 0 to 8 h after feeding and ammonia concentrations were higher (P < 0.05) both before feeding and 8 h after feeding when IBMU was fed than when any of the other supplements were fed. The concentration of isobutyric acid averaged 2.6-fold higher when IBMU was fed than when canola meal or soybean meal was fed, confirming that most of the compound was degraded in the rumen. Sheep fed IBMU had lower concentrations of acetic, propionic and butyric acid in the rumen than those fed natural protein supplements. It was unclear whether the decrease in VFA concentration was positive or negative in terms of nutritional value. It was concluded that IBMU exhibited some ideal characteristics for a nonprotein nitrogen supplement for ruminant animals because it was degraded at an optimum rate in the rumen and provided rumen microflora with isobutyric acid. Further experimentation is warranted to determine its usefulness when nitrogen-deficient diets are fed to ruminant animals. Key words: Nonprotein nitrogen, isobutyric acid, isobutyraldehyde, slow-release, isobutyraldehyde monourea, propanal-2-methyl-monourea
Effect of post-weaning protein supplementation of beef steers fed grass silage on performance during the finishing phase, and carcass quality
Authors: Petit Hélène V. , Veira D. M.
Published: March 2010

Seventy-two steers fed different proteins during a post-weaning phase were fed a common diet with or without protein supplementation during the finishing phase. Protein supplementation during finishing had no effect (P > 0.10) on animal performance. During finishing, BW gain tended (P = 0.07) to be affected by treatments fed during the growth phase. BW gain for the overall experiment was similar for all proteins and higher (P < 0.05) than that of steers fed only silage. During finishing, the feed:gain ratio was affected by diets fed during growth. Supplementation during growth decreased the time required to reach market weight with the lowest number of days being for steers fed fish meal. Carcass characteristics were similar for all treatments. Key words: Cattle, grass silage, growth, finishing, protein supplement
Hormonal concentrations during parturition in sows immunized against somatostatin
Authors: Farmer C. , Rushen J. , Brazeau P.
Published: March 2010

Concentrations of cortisol, insulin, growth hormone, insulin-like growth factor-I, triiodothyronine and thyroxine were determined before and during parturition in sows immunized against a somatostatin-BSA conjugate (n = 7) or against BSA only (n = 6). Immunization against somatostatin decreased insulin-like growth factor-I concentrations during parturition (P ≤ 0.05). For all animals, cortisol, thyroxine and triiodothyronine concentrations were greater (P ≤ 0.01) during than before parturition. Key words: Sow, parturition, somatostatin, cortisol, thyroxine, growth hormone, insulin-like growth factor-I
A study of hoof cracks in grazing cattle — association of age, weight and fatness
Authors: Goonewardene L. A. , Hand R. K.
Published: March 2010

The data were obtained from cow calf pairs and replacement heifers grazing summer pastures in northwest Alberta. The objectives were to study the association of age, weight, condition score, cow and calf gain on the prevalence, intensity and severity of hoof (sand) cracks and to determine if such cracks affected cow and calf average daily gain. Cows that had cracks were 1.5 yr older, 43 kg heavier and fatter than cows that showed no cracks. The prevalence of sand cracks was 20–21%. Whereas 3.4% of cows and heifers which were 1 and 2 yr old had cracks, 32.4% of the 3- to 5-yr old and 47.9% of the > 5-yr-old cows had cracks (P < 0.0001). Similarly while 8.4% of the lighter (< 522 kg) cows had cracks, 32.3% of the heavier (> 522 kg) cows had cracks (P = 0.003). Discriminant analysis showed that cows with cracks were older, heavier and fatter at the end of the grazing period. Age of cow, weight and fatness had no effect on intensity or severity of cracks. The presence or absence of cracks had no effect (P > 0.05) on cow or calf gains on pasture. Key words: Hoof cracks, prevalence, intensity, severity, age, weight, fatness
Antemortem handling effects on the behaviour, carcass yield and meat quality of market weight entire male pigs
Authors: Zawadski Sophie , Sather A. P. , Jones S. D. M. , Schaefer A. L. , Robertson W. M. , Tong A. K. W. , Squires E. J.
Published: March 2010

The effect of antemortem handling on behaviour, carcass yield and lean meat quality was determined on Lacombe and Yorkshire entire male pigs mixed within breed 24 h prior to slaughter and on entire males and gilts that were not mixed. In the period immediately after repenning (mixing), 40% of all recorded pen activity was observed, while 17% and 10% of the pen activities were recorded at 6 and 12 h after repenning. During the period immediately after transport to the abattoir, 33% of all pen activities were observed. Mixed pigs accounted for 78% of all activity. Yorkshire male pigs were three times as active as Lacombe male pigs during shipping. Thirty-six percent and 14% of the mixed Yorkshire and Lacombe male pigs had moderate skin blemishes, compared with 12% for unmixed Yorkshire male pigs. Moderate skin blemishes were absent in the unmixed Lacombe male and all female pigs. Dressing percentage and carcass shrinkage were unaffected by mixing during shipping. Dressing percentage was 23 g kg−1 higher in female than in male pigs, while male pigs had 20 g kg−1 greater lean than female pigs. Ultimate pH (48 h) was similar among unmixed pigs (5.53), but higher in mixed Lacombe (5.61) and Yorkshire (5.74) entire male pigs. Based on subjective meat quality evaluation, firm and dry pork was observed in 11% and 43% of the mixed Lacombe and Yorkshire male pigs, but was absent in unmixed male pigs. However, no consistent objective meat quality differences between unmixed male and female pigs were observed. Unmixed entire male pigs had superior carcass composition characteristics, with lean meat quality attributes at least equivalent to those of female pigs (e. g. pH, drip loss, CIE L*, hue angle). Mixing entire male pigs prior to slaughter had marginal but significant effects on carcass blemish scores and meat quality, particularly among Yorkshire pigs. This study suggests entire males, with appropriate antemortem handling, can produce superior carcasses, more efficiently and with pork quality at least equivalent to that of female pigs. Key words: Swine, behaviour, mixing, entire males, carcass yield, meat quality
Effects of ingredient particle size and feed form on the performance of Leghorn hens
Authors: Hamilton R. M. G. , Proudfoot F. G.
Published: March 2010

In each of two experiments, 1536 Leghorn pullets from two commercial genotypes (A and B) were given diets that were in the form of either mash, crumbles or pellets. The cereal grains used in these diets were either finely or coarsely ground using a hammer or roller mill. The particle size and form of the diets used were: FM, FMC, FMP, CM, CMC, and CMP. These diets were fed and data were collected when the birds were between 140 and 490 d of age.Pullets in exp. 2 were heavier at 140 d (P < 0.001) and lighter in weight at 490 d (P < 0.001), reached 50% EP 4.8 d earlier (P < 0.001), had 1.3% higher rate of EP (P < 0.05), and laid more large and small (P < 0.001) and fewer medium-sized (P < 0.01) eggs than those in exp. 1. Hens from genotype A had lower 140 and 490 d body weights (P < 0.001), 187 and 490 d egg weights and specific gravity (P < 0.001), better feed conversion (P < 0.001) and higher (P < 0.001) monetary returns than birds from genotype B. Birds receiving the FM and CM diets had higher EP (P < 0.05), feed intake (P < 0.001), monetary returns (P < 0.001), and numbers of medium-sized and small eggs (P < 0.05) than those fed the FMP and CMP diets. Specific gravity was higher (P < 0.001) for eggs laid at 187–188 d by the FMP and CMP-fed hens than for those given the FM or CM diets. In general, performance was better for the hens given the mash diets than for those fed the crumbled or pelleted diets. Key words: Particle size, feed form, hens
Feasibility of using cattle to disperse cicer milkvetch (Astragalus cicer L.) seed in pastures
Authors: Willms W. D. , Acharya S. N. , Rode L. M.
Published: March 2010

The passage of cicer milkvetch (Astragalus cicer L.) through the digestive tract of cattle was examined in relation to recovery, germination, and establishment. About 86% of seed ingested was recovered over a 4-d period. Most seed was excreted 24–48 h after ingestion and soft seed was reduced by about 3% for every 24-h period spent in the digestive tract. However, the field observation of 20 established plants indicates low efficiency of this method for dispersal of cicer milkvetch. Key words:Astragalus cicer, digestion, germination, soft seed, establishment, cattle
Effects of backfat thickness and carcass weight on the chemical composition and quality of the meat from culled sows
Authors: Aziz N. N. , Ball R. O.
Published: March 2010

A total of 204 sows, ranging in carcass weight from 73 to 279 kg and backfat thickness from 6.5 to 67.6 mm, were slaughtered and separated into four WC from < 119.9 kg to > 200 kg carcass weight in 40 kg increments and four FC from < 13.9 mm to > 32 mm backfat depth (probe fat) in 9-mm increments. Depth of fat (probe fat) and lean (probe lean) was measured between the 3rd and 4th last ribs 7 cm from the midline using an electronic probe. The left side was cut into four primals: shoulder, loin, ham and belly. All primals, except belly, were separated into lean, fat and bone. This dissected side lean, for 90 sows across WC and FC, was analyzed for protein, lipid, water and ash. Colour of LT and BF and drip loss of the loin muscle were also determined. As WC and FC increased, the proportion of lipid increased by 57.1% (P = 0.531) and 258.5% (P = 0.001), respectively. Water content of dissected lean decreased by 5.1% (P = 0.782) and 6.3% (P = 0.001) as WC and FC increased, respectively. Carcass weight and probe fat were significantly correlated with lipid percentage (r = 0.51 and 0.60, respectively) and chemical water percentage (r = −0.50 and −0.55, respectively) in side lean. As WC increased, both LT and BF became significantly darker. As FC increased, BF muscle became more yellow (P = 0.058). Drip loss was significantly associated with L* (r = 0.61) and b* (r = 0.63) values. The changes in the chemical composition of the separable lean were primarily a function of carcass fatness, whereas the brightness of the LT and BF were mainly influenced by WC. Key words: Sows, chemical composition, protein, meat colour, backfat depth
Variation in the chemical composition and test weight of barley and wheat grain grown at selected locations throughout Manitoba
Authors: Campbell L. D. , Boila R. J. , Stothers S. C.
Published: March 2010

Cultivars of wheat (n = 8) and barley (n = 6) were grown at 12 locations throughout Manitoba over 3 consecutive years. Test weight (TWT = weight of whole grain per volume), and the concentrations of protein, starch, fat, NDF and ADF in the grain from wheat and barley differed (P < 0.05) among cultivars of each grain. Correlation coefficients between measurements were calculated for barley: TWT vs. starch, r = 0.43; TWT vs. NDF, r = −0.66; TWT vs. ADF, r = −0.51; starch vs. NDF, r = −0.49; and they were also calculated for wheat: TWT vs. protein plus starch, r = 0.26; TWT vs. NDF, r = −0.44; TWT vs. ADF, r = −0.31; protein vs. starch, r = −0.50. Variation for TWT and the concentrations of protein, starch, fat, NDF and ADF in the grain from barley and wheat were due both to differences among cultivars and the effect of environment (location and year of growth) on those differences among cultivars. Effects of environment differed among measurements. Variance due to the interaction between cultivar, and location and year of growth (cultivar × environmental variance) was 7.5 and 14.0% of total variance (total variance = environmental variance plus cultivar × environmental variance) for protein in barley and wheat, respectively. Cultivar × environmental variance was also low and ranged from 24.0 to 35.4% of total variance for starch, NDF and ADF in barley and for ADF in wheat. The lower the percentage of cultivar × environmental variance the more predictable were the differences for a measurement among cultivars of a grain across environments. Key words: Grain, wheat, barley, composition, test weight, Manitoba
Feeding frequency and its effect on feedlot performance in steers
Authors: Goonewardene L. A. , Engstrom D. F. , ZoBell D. R.
Published: March 2010

One hundred and twenty commercial feedlot steers were penned and randomly allocated to three treatments: fed once, twice and three times per day, over a grower through finisher period of 196 d. Feeding frequency had no effect (P > 0.05) on average daily gain, feed intake or efficiency overall. We conclude that there are no beneficial effects in feeding a total mixed diet more frequently to feedlot steers. Key words: Feeding, frequency, gain, steers, feed efficiency
Feeding strategies during the lactation period for first-parity sows
Authors: Genest M. , D'Allaire S.
Published: March 2010

The effects of different feeding regimes during the lactation period on feed intake, body reserves and sow performance were evaluated. A 2 × 2 factorial design was used and 183 first-parity sows were randomly allocated to one of four treatments: sows were fed either two or three meals per day with (wet feed) or without (dry feed) supplemental water at meal time. Primrparous sows were fed ad libitum 12–16 h after parturition. The addition of water at meal time increased (P < 0.01) feed consumption by 5% over the 18-d lactation period. Increased feeding frequency did not influence feed intake. During the first week of lactation, most sows gained weight, but thereafter lost weight, with the rate of weight loss reaching a peak during the last week of lactation. Although feed intake was influenced only by wet feeding, both an increased frequency of daily meals and the use of wet feeding reduced mobilization of body reserves. Wet-fed sows lost less weight than dry-fed sows and the increased feeding frequency reduced backfat loss. Average daily gain of piglets, percentage of sows with a weaning-to-estrus interval of less than 7 d, farrowing rate, and parity-2 litter size were similar among the four groups. A lack of significant improvement in sow performance with different regimes may be partly related to a generally high feed intake and minimal weight and backfat losses. Although our results failed to show a benefit on sow performance, we believe that some of the feeding strategies evaluated could be useful during periods in which sows eat less, such as in the summer, or in some herds that have feed consumption problems. Key words: Sow, feed intake, weight, backfat, reproductive performance
A histochemical and immunohistochemical study of proteoglycans in normal and osteochondrotic joint cartilage of swine
Authors: Nakano T. , Aherne F. X.
Published: March 2010

Proteoglycans were studied histochemically and immunohistochemically in normal and osteochondrotic cartilage of swine. The results showed reduced intensities of proteoglycan staining with cationic dyes in osteochondrotic necrotic cartilage. Staining intensities with monoclonal antibodies specific to chondroitin sulfate, keratan sulfate and decorin varied among joints. These results do not support recent reports demonstrating high staining intensity of proteoglycan in necrotic cartilage. Key words: Osteochondrosis, cartilage, pig, immunohistochemistry, proteoglycan
Cattle use of microclimates on a northern latitude winter range
Authors: Houseal G. A. , Olson B. E.
Published: March 2010

Grazing native range can help lower costs of wintering livestock. However, extreme cold and wind can negatively affect an animal's thermal balance, increasing energy demand when the nutritive value of the forage is low. Free-ranging cattle (Bos taunts) may exploit differences in topography and microclimate to minimize or avoid environmental stressors such as high winds and cold temperatures. Cattle selection of microclimates in response to cold stress was studied over a 6-wk period for two consecutive winters. The objective of this study was to determine if cows respond to extreme wind and cold by selecting moderate microclimates for foraging. Cattle selected moderate microclimates for grazing and resting to avoid high winds and cold temperatures. They also tended to remain in microclimates above their lower critical temperature (LCT) of −23 °C, even though reference climate conditions often were below their LCT. The availability of moderate microclimates in a pasture may allow cows to continue grazing, thus maintaining intake, even when general conditions might otherwise cause them to defer from grazing. Key words: Behavior, winter ecology, Bos taunts, microclimates, thermoneutral
A solid-phase enzymeimmunoassay for the determination of progesterone in bovine, porcine and ovine plasma
Authors: Vecchio R. P. Del , Sutherland W. D. , Connor M. L.
Published: March 2010

The purpose of this project was to develop a valid quantitative enzymeimmunoassay (EIA) for progesterone in blood plasma of cattle, pigs and sheep. Rabbit anti-progesterone, mouse monoclonal anti-rabbit IgG, authentic progesterone, and acetylcholine esterase bound covalently to progesterone were the principal reagents used to develop the EIA. Ninety-six well microliter plates were coated with mouse monoclonal anti-rabbit IgG and saturated with bovine serum albumin before use. Rabbit anti-progesterone was diluted to a working dilution of 1:2.0 × 106. Standard curves were linear and ranged from 1.56 to 400 pg of progesterone per well which allowed for the measurement of 0.03125 to 8.0 ng mL−1. Assay sensitivity averaged 1.56 pg well−1. Progesterone was extracted from plasma samples with petroleum ether. Plasma samples (n = 3 or 4 from each species) with unknown amounts of progesterone that were extracted and serially diluted with EIA buffer did not deviate from parallelism with progesterone standard curves in buffer. The correlation between EIA and radioimmunoassay (RIA) measurements of progesterone in the same plasma samples was high (P < 0.0001) for all three species (r = 0.96 for bovine; r = 0.96 for porcine; r = 0.94 for ovine). The regression of EIA data on RIA data produced the following equations:[Formula: see text]The intra- and inter-assay coefficients of variation were 5.4 and 10.6% for bovine, 5.8 and 11.0% for porcine and, 6.1 and 12.3% for ovine, respectively. These data show that this EIA is a valid and reliable memod for quantitating progesterone in extracts of bovine, porcine and ovine plasma. Key words: Enzymeimmunoassay, progesterone, plasma, bovine, porcine, ovine
The effect of alpha2-adrenoceptor stimulation with guanfacin on thermogenesis in fasted and fed sheep
Authors: Miaron J. O. O. , Christopherson R. J. , Hardin R. T.
Published: March 2010

Eight sheep with an average body weight of 99 kg were divided into two groups (fasted and fed) of four and kept in individual pens. The sheep were used to examine the effects of alpha2-adrenoceptor stimulation on heat production, heart rate, rectal temperature, skin temperature and plasma parameters. On the day of the experiment, food but not water was withheld from the fasted group and the fed group received 1.0 kg of pelleted alfalfa diet. The treatments consisting of vehicle (saline) and three levels (low = 0.8 mg; medium = 1.6 mg; high = 2.4 mg per sheep) of guanfacin were administered intravenously in a split-plot experimental design. The heat production was determined by open circuit respiration calorimetry, the heart rate was recorded by an electrocardiograph and the rectal and skin temperatures were measured with a Fisher Digital Thermometer. When compared to saline, guanfacin reduced (P < 0.05) the heat production of fasted sheep (1.21 vs. 0.99, 1.09, 0.98 W kg−1) for the low, medium and high doses, respectively. For the fed sheep the medium and high doses reduced total post-feeding heat production (1.64 vs. 1.43, 1.55 W kg−1). The difference in heat production between the fed and fasted animals was not altered by guanfacin. The skin temperature was reduced by all doses of guanfacin in the fasted sheep but only by the high dose in the fed sheep. The heart rate was not affected by guanfacin. The high dose increased the rectal temperature of fed sheep. In both groups the high dose resulted in a decrease (P < 0.05) in blood haemoglobin content. Guanfacin induced a two- to threefold increase in plasma glucose and a transient response in insulin concentration. We conclude that short-term alpha2-adrenoceptor stimulation with guanfacin suppresses the heat production of both fasted and fed sheep but has no effect on the heat increment of feeding. Key words: Calorimetry, alpha2-adrenoceptors, guanfacin, feeding, sheep