bluuebunny/crossref_metadata_2025 huggingface dataset:
An empirical check on best linear unbiased prediction genetic evaluation using pig field recording data
Authors: Quinton V. M. , Smith C.
Published: March 2010

The theory and use of best linear unbiased prediction in genetic evaluation are well developed. However, there has been little empirical checking of its efficacy in practice. The objective here was to use a large body of Canadian pig performance records to check on the predicted benefits of BLUP in genetic evaluation. Phenotype records were available on fat depth and on days to 100 kg on some 65 000 progeny born in 1994 and 1995 from parents evaluated before 1994. Rank correlations between parent and progeny in data were calculated within herd-year-season to avoid effects due to differences in these factors. Computer simulation studies were also run to check on the predicted results. The simulation results confirmed the expectations on the higher correlation of mid-parental EBV than of mid-parental phenotype with progeny genotype and a regression (of progeny phenotype on mid-parental EBV) of unity when all relevant pedigree and performance data were used. In the data analysis, the (rank) correlations with progeny phenotype were consistently higher (36 and 27%) for mid-parental BLUP genetic evaluation than for mid-parental phenotypes, confirming the superiority of the BLUP evaluations over phenotypes. However, the regression of progeny phenotype on mid-parent BLUP EBV was usually less than the predicted value of unity. Simulation results suggest that either the base population heritability was lower than that used in the evaluation or that the information used was incomplete. Key words: Best linear unbiased prediction, EBV, pigs, performance, selection
The effect of peroral and intracaecal 3-methylindole administration on the quantitative absorption to the portal vein in growing intact male pigs
Authors: Laue A. , Hansen-Møller J. , Agergaard N.
Published: March 2010

This study intends to extend knowledge on the fate of intestinal 3-methylindole (3MI) in vivo as the substance is a key causative agent in the expression of boar taint in pig carcasses. Eleven multi-catheterized and caecum-fistulated intact male pigs were used to examine the effects of peroral and intracaecal challenges of 1, 5 and 10 mg 3-methylindole per kilogram body weight (BW) on the quantitative net absorption from specific sites of the alimentary canal (AC), measured as 3MI portal net appearance (PNA). Faeces were collected once a day while portal, hepatic and jugular vein as well as arterial blood were collected during the experiments lasting 300 min. Portal blood flow was recorded by ultrasonic blood flow probes. The BW of the pigs averaged 73 to 89 kg at the beginning and end of the experiments. All pigs on the untreated control treatment absorbed 3MI from the AC. Faecal 3MI concentrations did not differ between control and 3MI-treated pigs. On the other hand, an evident difference was observed in the PNA between the controls with an average of 11.2 mg 3MI (300 min)−1 and 3MI-treated animals varying from 23.9 to 308 mg 3MI (300 min)−1 After application of 3MI, the net absorption from the AC to the portal blood plasma increased up to 147 times. Depending on the site of administration and the dosage application, plasma peak values of 3MI occurred within the first 30 min after the challenge. Within the doses of 1 to 10 mg 3MI (kg BW)−1, no absorption plateau was to be reached. The observed rapid absorption of 3MI leads to the assumption that the mechanism is mainly by passive diffusion. Intravenous 3MI injections indicated diffusion from the blood circulation to the intestinal lumen. The site of administering exogenous 3MI was of less importance for the PNA than the dosage applied. This implies that the permeability for 3MI along the AC is identical, no matter where it is introduced. Results indicate a proportional relation between the 3MI dosage administered and the PNA. Finally, it was observed that a) pigs with high (pre-experimental) initial PNAs subsequently also absorbed more 3MI after challenges of additional 3MI, expressed as PNAs; and b) pigs with increasing BW exhibited higher PNAs, indicating a rise of 3MI absorption with advancing age. Key words: Boar taint, 3-methylindole, quantitative absorption, pig, portal vein, skatole
Effects of high dietary levels of silver hake and Atlantic herring on growing-furring performance and blood clinical-chemistry of mink (Mustela vison)
Authors: Rouvinen K. I. , Anderson D. M. , Alward S. R.
Published: March 2010

An experiment was conducted with a total of 168 mink (Mustela vison) of the standard black genotype to determine the effects of dietary silver hake (Merluccius bilinearis), silver hake silage and herring (Clupea harengus) on the growing-furring performance. There were seven dietary groups. The control diet (CONTROL) contained 40% haddock offal, 8% poultry offal, 15% beef tripe and lungs, 5% corn gluten meal, 12% extruded wheat, 0.4% vitamin-mineral premix, and water. Test diets were made by replacing the fish offal with 15 or 30% hake (HAKE 15, HAKE 30), hake silage (SILAGE 15, SILAGE 30) or with 40% herring (HERRING 40). The last dietary group (HERR/CONT) was fed alternatingly with the CONTROL or the HERRING 40 diets. The animals in the HERRING 40 group developed anorexia after 2 wk on the test diet and were injected with vitamin B complex. The diet was supplemented with thiamin, 25 mg kg−1 feed. This restored appetite and supported normal growing-furring performance. Mink fed HAKE 30 diet had a lower weight gain from weaning until pelting (males 814 ± 58.0 g, females 366 ± 53.6 g) than the CONTROL (males 987 ± 61.9 g, females 429 ± 52.1 g)(P < 0.05). Blood haemoglobin (Hb) values for all groups were on average 178 ± 4.4 g L−1 in September and 184 ± 7.0 g L−1in October, i.e. well above the critical level to prevent the development of cotton fur. However, the total amount of iron stored in spleen and liver was lower for the HAKE 30 (562.1 ± 85.1 µg) and SILAGE 30 (435.9 ± 77.7 µg) groups than in the CONTROL (800.7 ± 77.7 µg) (P < 0.05) possibly indicating impaired absorption. No signs of poor pigment development were seen in the underfur of the winter pelage. Both silver hake and herring show good potential as alternative feedstuffs in growing-furring diets for mink. At high inclusion levels the effects of thiaminase enzyme in herring and the iron-binding trimethylamine oxide in silver hake should be accounted for. Key words: Mink, herring, thiamin, silver hake, fish silage, iron
The effect of micronization of full-fat canola seed on digestion in the rumen and total tract of dairy cows
Authors: Wang Y. , McAllister T. A. , Zobell D. R. , Pickard M. D. , Rode L. M. , Mir Z. , Cheng K.-J.
Published: March 2010

The effect of micronization of full-fat canola seed on dry matter disappearance (DMD) and total nitrogen disappearance (TND) in the rumen and intestine were investigated. Full-fat canola seed was left untreated (C) or micronized for 1.5 min (M), and left whole (CW, MW) or ground to pass through a 1.25-mm sieve (CG, MG). In vitro gas production from CW and MW were determined at 0, 1, 2, 3, 8, 12, 20, 24, 32, 48, 52, 68 and 72 h. For subsequent studies, CW was hand-cracked (CH) for comparison against MW. In situ DMD and TND from CH, MW, CG and MG were determined after 0, 2, 4, 8, 16, 24, 48 and 96 h of ruminal incubation. The mobile nylon bag technique was used to estimate intestinal digestion (DM and N disappearance) of samples incubated in the rumen for 16 h and in acid-pepsin for 1 h. Scanning electron microscopy revealed the pattern and extent of seed coat rupture from hand-cracking and from micronization to be similar, but micronization-mediated changes to the internal structures were evident in ground samples. Micronization increased (P < 0.05) in vitro gas production from whole canola seed (CW vs. MW), but relative to CH, DMD and TND from MW were lower (P < 0.001) in situ and in the whole digestive tract (P < 0.001). Estimated intestinal DMD and TND did not differ (P > 0.05) between CH and MW. Ruminal DMD and TND from ground seed were reduced (P < 0.05) by micronization (CG vs. MG) in the rumen, but intestinal DMD and TND were increased (P < 0.05 and P < 0.01, respectively), thus in the whole digestive tract, these values did not differ (P > 0.05) between treatments. Micronization reduced potential ruminal protein degradability (P < 0.05) and effective ruminal protein degradability (P < 0.01) of full-fat canola, and in combination with grinding, increased the proportion of protein digestion in the intestine. Key words: Micronization, full-fat canola seed, digestibility, rumen, dairy cow, in situ
Interactive effects of selection for lower backfat and dietary pyridoxine levels on reproduction, and nutrient metabolism during the gestation period in Yorkshire and Hampshire sows
Authors: Knights T. E. N. , Grandhi R. R. , Baidoo S. K.
Published: March 2010

Two experiments were conducted to determine the interactive effects of selection for lower backfat over six generations, and two dietary supplemental pyridoxine levels (1.0 vs. 15.0 ppm) on sow reproductive performance and nutrient metabolism in second-parity Yorkshire and Hampshire sows. Feeding increased pyridoxine at 16.0 vs. 2.6 ppm from day of weaning through gestation did not improve (P > 0.05) the sow reproductive performance in experiment 1 (N = 32) or 2 (N = 66). In exp. 2, feeding increased pyridoxine reduced the weaning to estrus interval (4.6 vs. 5.7 d, P = 0.11). It also increased the average daily apparent retention of nitrogen during gestation in both experiments 1 (17.2 vs. 7.8 g, P = 0.11) and 2 (10.5 vs. 5.0 g, P = 0.10). Sows fed increased pyridoxine had higher (P < 0.01) plasma pyridoxal and pyridoxic acid levels throughout the gestation period. The overall results indicate that increased dietary pyridoxine tended to have a positive influence on sow weaning to estrus interval and nitrogen metabolism, and it also tended to have a positive influence on litter size only in Yorkshire select line of sows. Key words: Breed, line, sows, pyridoxine, reproduction, metabolism
Effect of water-soluble extract from antler of wapiti (Cervus elaphus) on the growth of fibroblasts
Authors: Sunwoo H. H. , Nakano T. , Sim J. S.
Published: March 2010

The water-soluble extracts were prepared from the tip sections of antlers of 4-yr-old wapiti stags, and the effect of extract on the growth of bovine skin fibroblasts in culture was examined. The results showed the presence of growth promoting factor(s) in the antler extract. The stimulation of cell growth was found to be dose dependent (P < 0.05). Key words: Growth factor, antler, wapiti, fibroblast
Grazing system and stocking rate effects on the productivity, botanical composition and soil surface characteristics of alfalfa-grass pastures
Authors: Popp J. D. , McCaughey W. P. , Cohen R. D. H.
Published: March 2010

A 4-yr experiment was conducted (1991 to 1994) near Brandon, MB, to determine the effects of grazing system (continuous and rotational) and stocking rate [light (1.1 steers ha−1); heavy (2.2 steers ha−1)] on the productivity, botanical composition and soil surface characteristics of an alfalfa (Medicago sativa L.; approximately 70%), meadow bromegrass (Bromus biebersteinii Roem & Schult.; 25%) and Russian wild ryegrass [Psathyrostachys juncea (Fisch.) Nevski; 5%] pasture. Grazing season length was shorter (P < 0.05) for cattle in continuously compared with rotationally stocked pastures in 1991, while in 1993 and 1994 it was shortest (P < 0.05) in heavily stocked continuously grazed pastures. Carrying capacity (steer days ha–1) was greater (P < 0.05) in heavily stocked rotationally grazed pastures compared with other treatments in 1991, 1993 and 1994. In 1992, it was greater (P < 0.05) in heavy than light stocking rate treatments for both rotationally and continuously grazed pastures. Cattle usually gained more (P < 0.05) per day (kg d−1) and during the season (kg hd−1) at light than at heavy stocking rates, while total liveweight production (kg ha−1) was greater (P < 0.05) at heavy than at light stocking rates. Forage production and disappearance did not differ (P > 0.05) within grazing systems and stocking rates from 1991 to 1993, but in 1994, production and disappearance were greater (P < 0.05) at heavy than at light stocking rates. Mean seasonal herbage mass available and carry-over were greater (P < 0.05) in lightly stocked pastures than heavily stocked pastures from 1991 to 1994. After the first year of grazing, the proportion of alfalfa increased (P < 0.05), while grasses declined (P < 0.05) within all grazing treatments. In subsequent years, a trend was observed, where alfalfa declined and grasses increased in all pastures, except those stocked heavily and grazed continuously, which by 1994 had the greatest (P < 0.05) percentage of alfalfa. As years progressed, increases (P < 0.05) in basal cover concurrent with declines in bare ground were recorded on all grazing treatments, while litter cover often did not differ (P > 0.05) within either grazing system or stocking rate, except in 1992, when basal cover was lowest (P < 0.05), while litter cover was greatest (P < 0.05) on lightly stocked continuously grazed pastures compared with other treatments. Stocking rates were a key factor to optimizing individual animal performance and/or gain per hectare on alfalfa grass pastures, however differences in the effect of continuous and rotational stocking on pasture productivity were minimal. Key words: Alfalfa, grazing, stocker cattle, production
Relationships of early performance traits to lifetime profitability in Holstein cows
Authors: Kulak K. K. , Dekkers J. C. M. , McAllister A. J. , Lee A. J.
Published: March 2010

Relationships of first lactation traits to lifetime profitability were studied based on data of 1112 lifetime performance records of purebred Holstein cows from the National Cooperative Dairy Cattle Breeding Project, which was implemented by Agriculture Canada in 1972. Lifetime profit was defined based on milk production, body weight, reproductive performance, herdlife, and prices for feed energy, milk, calves, salvage value, and fixed costs. First lactation traits with significant relationships to lifetime profitability were identified using the backward elimination procedure for least squares. Relative weights of each prediction trait were expressed as standard partial regression coefficients. Milk revenue in first lactation was the most important trait, followed by 3 min yield, and udder height. First lactation survival was found to be significant. Increasing age at first calving, number of days from first breeding to conception in first lactation, and teat diameter had significant negative effects on profit. Health traits in first lactation were not significant. The significant traits explained 35% of total variation in lifetime profitability. Key words: Dairy cow, lifetime profitability, early indicator traits
Culling in Quebec Holstein Herds. 1. Study of Phenotypic Trends in Herd Life
Authors: Dürr J. W. , Monardes H. G. , Cue R. I. , Philpot J. C.
Published: March 2010

A total of 206 963 official lactation records and 128 182 owner sampler lactation records from the Programme d'Analyse des Troupeaux Laitiers du Québec herds were used to estimate survival rates of Holstein cows up to different parities by milk recording option and year of first calving. Survival up to a given parity was computed only for cows having the opportunity to reach that parity. Average productive herd life up to and including the eighth parity was computed for cows calving for the first time from 1981 to 1985. The overall productive herd life was 33.13 mo for owner sampler herds and 32.97 mo for official herds, and the respective replacement rates per year were 36.22% and 36.40%. Average herd composition in Quebec Holstein herds was: 33.4% of cows in parity 1, 24.2% in parity 2, 17.1% in parity 3, 11.4% in parity 4, 7.0% in parity 5, 3.9% in parity 6, 1.9% in parity 7, and 1.1% in parity 8. Cows in official herds had longer calving intervals than those in owner sampler herds. First calf heifers have been culled by official producers earlier in lactation than by owner sampler producers. Survival rates decreased from 1981 to 1992, and trends for official and owner sampler herds were very similar. Key words: Herd life, survival, Holstein, Quebec, culling
Development of pale, soft, exudative pork in halothane-negative pigs through post-mortem infusion
Authors: Dugan M. E. R. , Aalhus J. L. , Murray A. C. , Larsen I. L. , Best D. R.
Published: March 2010

A single-limb infusion of post-mortem muscle was used to determine the effect of calcium salts and calcium chelators on post-mortem metabolism and meat quality. Regardless of the type of infusate, the infusion process itself resulted in an acceleration of glycolysis, increased drip loss, paler meat colour (shifts in L* and hue angle) and decreased shear. The observed tenderization as a result of these infusions sheds some doubt that the calpain enzyme system is solely responsible for post-mortem tenderization. Key words: Pork; pale, soft, exudative; single-limb infusion; tenderization
Methane production by steers on pasture
Authors: McCaughey W. P. , Wittenberg K. , Corrigan D.
Published: March 2010

In order to determine the quantity of methane (CH4) produced by steers on pasture, 16 steers with a mean weight of 356 ± 25 kg were randomly selected from a larger group of cattle (n = 48) to evaluate the effects of grazing management and monensin controlled release capsule (CRC) administration on ruminal CH4 production using the sulphur hexafluoride (SF6) tracer-gas technique. Pasture management treatments consisted of two grazing systems (continuous stocking or 10-paddock rotational stocking) at each of two stocking rates (low, 1.1 steer ha−1 or high, 2.2 steers ha−1) with two replications of each pasture treatment. Half of the animals on each pasture treatment were administered a monensin CRC delivering 270 mg d−1, and untreated animals served as controls. During the 140-d grazing season, one steer from each treatment-replicate combination was sampled to determine daily intake and CH4 production on four occasions. The chemical composition of diets differed between grazing management treatments and sampling periods. Voluntary intake and CH4 production, adjusted for differences in body weight, were unaffected by grazing management, sampling period or by monensin CRC administration and averaged 0.69 ± 0.1 L kg BW−1 d−1 across all grazing management treatments. The energy lost through eructation of CH4 averaged 4.5 ± 1.4% of gross energy intake. Key words: Methane, cattle, environment, digestion efficiency, pasture, forage
Effects of selection for lower backfat, and increased dietary lysine level to digestible energy with supplemental threonine and methionine on lactation performance of Yorkshire and Hampshire sows
Authors: Grandhi R. R.
Published: March 2010

Two experiments were conducted, using a total of 95 second-parity and 43 third-parity Yorkshire and Hampshire sows to determine the effect of selection for lower backfat, and increased dietary lysine level to DE with supplemental threonine and methionine on sow lactation performance. The sows were from two genetic lines, one kept as control and the other selected for lower backfat thickness over six generations. The dietary amino acid levels to DE used in the two barley-wheat-soybean meal lactation diets (14.0 MJ kg−1 DE) were: 1) 0.43 g lysine MJ−1 with no supplemental amino acids, and 2) 0.68 g lysine MJ−1 with supplemental threonine and methionine at 0.65 and 0.3 ratios to lysine. In exp. 1 (third parity sows), feeding diet 2 increased the sow weight gains (4.5 vs. −0.4%, P = 0.02) and average daily feed intake (7.8 vs. 7.2 kg, P = 0.07), while reducing backfat losses (−4.7 vs. −10.5%, P = 0.09) during the 4-wk lactation period. Feeding diet 2 also significantly increased the piglet weight gains by 10.4 and 11.7% at both 3 and 4 wk of age, respectively, while piglet survival rate was improved by about 5%. In exp. 2 (second-parity sows) also, feeding diet 2 increased the sow weight gains (1.1 vs. −3.0%, P = 0.01) with little improvement in average daily feed intake (6.8 vs. 6.5 kg) and reduction in backfat loss (−2.0 vs. −1.0%) during lactation. Feeding diet 2 also significantly increased the piglet weight gains by 9.1 and 7.3% at both 3 and 4 wk of age, respectively. The overall results indicated that feeding 0.68 g lysine to MJ−1 DE with supplemental threonine and methionine at a ratio of 0.65 and 0.30 to lysine improved the lactation performance in both second- and third-parity sows, and this response tended to be more consistent in sows selected for lower backfat. Key words: Breed, lysine, amino acids, energy, sows, lactation
Supplementation with chromium picolinate reduces the incidence of placental retention in dairy cows
Authors: Villalobos-F. J. A. , Romero-R. C. , Tarragó-C. M. R. , Rosado A.
Published: March 2010

A test with two groups (n for each group = 25) of Holstein cows was conducted to evaluate the effects of chromium picolinate (CrPic) on the incidence of placenta retention (PR). Organic chromium supplementation, equivalent to 3.5 mg Cr d−1 per cow, administered during the last 9 wk of pregnancy, decreased nearly four times the incidence of placental retention observed in unsupplemented cows (16% vs. 56%, P < 0.05, chi square test). Calf body weight (BW) at birth was similar in both groups (without Cr = 43.92 ± 0.75 kg vs. Cr supplementation = 44.26 ± 0.84 kg). Key words: Placental retention, chromium picolinate, stress, dairy cows
Herbage biomass and intake of beef cows with calves grazing a grass-legume pasture in southern Ontario
Authors: Marshall S. A. , Campbell C. P. , Buchanan-Smith J. G.
Published: March 2010

Intake and performance of 40 spring-calving cows with calves was investigated under a rotational grazing management system across three consecutive summers. A 19.2 ha pasture was divided into sixteen 1.2 ha fields with each field being further subdivided into eight 0.15 ha paddocks. Five cows with calves belonging to one of two breed groups (large vs. medium framed) and two body conditions (high vs. low) were randomly assigned to graze each of eight field pairs from May to October of each year. Paddocks not grazed by cow-calf pairs were grazed by yearling heifers or mechanically harvested as hay or silage. Grazing was managed by setting target sward heights for exit of each paddock at 8 to 10 cm and allowing a minimum of 25 to 30 d for regrowth. Paddocks were topclipped and fertilized with 34 kg ha−1 of nitrogen (N) immediately following the second grazing of each paddock. Sward surface height data were collected from 40 measurements taken immediately pre- and post-grazing in each paddock as well as during the regrowth period. Herbage biomass and quality was determined in year 1 by handclipping 10 quadrats (1.22 m × 0.15 m) from each paddock pre- and post-grazing and by clipping 7 similar quadrats from alternate paddocks in each of the other 2 yr. Average pre-grazing sward heights were 24.8, 30.3 and 28.1 cm, in years 1, 2 and 3, respectively. Herbage biomass available for grazing averaged 7.59, 10.62 and 11.04 tonnes DM ha−1 for years 1, 2 and 3, respectively. A positive linear (r = 00.93 P < 0.0001) relationship was established between sward height (cm) and herbage biomass (kg DM ha−1) across all 3 yr. Intake of dry matter (DM), crude protein (CP) and metabolizable energy (ME) was higher for both large- and medium-framed cow-calf pairs in year 3 than in the other 2 yr. Both large- and medium-framed cows lost (P < 0.05) body condition in years 1 and 2, but gained in year 3. Cows from the low body condition group gained (P < 0.05) more than those from the high group in years 2 and 3. Medium-framed calves gained more (P < 0.05) in year 3 than in years 1 and 2. Body condition of cows grazing a multi-species grass-legume pasture can be maintained if not improved provided seasonal variations in quality and quantity are minimized. Key words: Beef cows, pasture, grass-legume, intake
A comparison of textured versus pelleted concentrates on rumen degradability, dry matter intake, milk yield and composition in lactating Holstein cows
Authors: Keyserlingk M. A. G. von , Gardner W. C. , Fisher L. J. , Shelford J. A.
Published: March 2010

A study was undertaken to compare the feeding of a ground-pelleted concentrate mixture with a textured one. Parameters studied were in situ rumen degradability characteristics of the concentrates, dry matter intake and yield of milk and milk components. A concentrate mixture consisting of barley, corn, canola meal and a vitamin-mineral premix was manufactured in two forms. In the one form, all ingredients were ground and pelleted while in the second, only the canola meal and premix were pelleted while the corn and barley were steam rolled prior to mixing. Initially the degradability characteristics and digestive tract disappearance of the two concentrates were determined in an in situ trial using two non-lactating Holstein cows fitted with rumen and duodenal cannulae. Nylon bags containing 2–3 g of material were prepared in quadruplicate (two replicates per cow per incubation time) and incubated in reverse order 72, 48, 24, 12, 8, 4, 2 and 0 h for each concentrate. Total intestinal disappearance was determined using the mobile nylon bag procedure. The results of the in situ trial indicated that the degradable fraction b of the dry matter was greater for the textured compared with the pelleted form (34.7 vs. 31.2%) while effective degradability of the dry matter was higher for the pelleted form (74.5 vs. 68.0%). Total tract disappearance of the dry matter and protein fractions were not influenced by form of concentrate but rumen disappearance of crude protein was higher for the pelleted form (70.4 vs. 64.2%). The feeding trial employed 14 lactating Holstein cows fed a forage mixture consisting of corn silage and grass silage. Milk and milk protein yields and protein content of the milk were higher, while milk fat content was lower, for cows fed the pelleted compared with those fed the textured concentrate. Rumen pH (6.79 vs. 6.58) was lower for cows fed the pelleted compared with the textured concentrate. There was, however, no effect of form of concentrate on concentrations of volatile fatty acids in the rumen fluid. Form of concentrate fed did not influence dry matter intake but in terms of net energy (Mcal NEL) the diet containing the pelleted concentrate tended to have a higher energy value than the diet containing the textured concentrate (1.76 vs. 1.66 Mcal NEL kg DMI−1). The marked difference in the ratio of milk fat to milk protein, 1.14 vs. 1.29 for pelleted and textured concentrates, respectively, coupled with the impact on rumen degradability characteristics indicated that minor differences in processing can have an impact on product yield from the milk and the efficiency of utilization of the diet. Key words: Textured versus pelleted concentrate, degradability, lactating cows
Protein supplementation to enhance the performance of pregnant cows on rough fescue grasslands in winter
Authors: Willms W. D. , Rode L. M. , Freeze B. S.
Published: March 2010

Rough fescue grasslands are readily damaged with heavy grazing pressure in the summer but tolerate grazing in winter. In addition, these grasslands have physical and nutritive properties that make them favourable for winter grazing by cattle, which reduces the cost of winter feeding while preserving the integrity of the grasslands. This study was conducted on the rough fescue grassland to determine the impact of protein supplementation on pregnant Hereford cows and the effect of supplementation on forage intake. A secondary objective was to determine the winter quality of forage from this grassland as measured by crude protein (CP), phosphorus (P), and acid detergent fibre (ADF) of selected species. The study site was in the rough fescue grasslands at the Agriculture and Agri-Food Canada Range Research Substation west of Stavely, AB. A canola based supplement (32% CP) with added minerals was fed to pregnant Hereford cows at four levels [0, 0.4, 0.8, and 1.2 kg d−1 per animal] from 1 November to 31 January over 3 yr. Two animals were used in each of 12 paddocks (1.67 ha each) arranged in a randomized complete block design with three blocks. Cow weight and backfat were recorded before and after each feeding period. Forage biomass and feed intake were estimated by harvesting plots before and after grazing, and with the use of a non-destructive method based on measurements of individual plants that allowed estimates for each forage species. Cow weights were affected (P = 0.002) by supplementation. Cows receiving 0.4 kg d−1 supplement lost the most weight while cows receiving 0.8 or 1.2 kg d−1 lost the least. Backfat was not responsive to supplementation (P > 0.05). Rough fescue grasslands must be in good condition to be able to support winter grazing because rough fescue provides most of the forage utilized by cattle in winter. Key words: Winter grazing, Festuca campestris, rough fescue, weight loss, backfat, digestibility, beef cattle
Effects of chronic parenteral pyridoxine and acute enteric tryptophan on pyridoxine status, glycemia and insulinemia stimulated by enteric glucose in weanling piglets
Authors: Matte J. J. , Ponter A. A. , Sève B.
Published: March 2010

In order to investigate the importance of the relation between pyridoxine and tryptophan on glucose tolerance and insulin response to glucose, 12 Large White × Pietrain piglets (males and females), weaned at 3 wk of age, were allocated to two treatment groups. Within each of the six pairs (four females and two males), one piglet received daily 3 mL i.m. of pyridoxine.HCl (5 g L−1) and the other received a control injection of saline. The animals were fed a liquid feed through a gastric tube surgically inserted on the day of weaning. Seven days later, one catheter was placed in the duodenum and another in the jugular vein. One week after recovery, the piglets received an intraduodenal infusion of glucose or glucose + tryptophan; 2 d later, each piglet received the opposite treatment. There was no effect (P > 0.18) of the administration of pyridoxine.HCl on plasma pyridoxal and pyridoxal-5-phosphate. Whatever the pyridoxine treatment, the plasma glucose response was lower (P ≤ 0.05) after the glucose + tryptophan infusion than after the glucose infusion. There was, also, an interaction between parenteral pyridoxine and duodenal infusion on changes in plasma insulin concentrations following the duodenal infusion (P ≤ 0.02). The greatest response, observed in piglets supplemented with pyridoxine.HCl and infused with glucose, was 55% higher than for the three other treatments. Further work is needed for an eventual reliable estimate of the pyridoxine status and requirements of weanling piglets. The tryptophan and pyridoxine effects on insulin metabolism suggest a different action of these nutrients on sensitivity and release of insulin. Key words: Pyridoxine, tryptophan, glucose, insulin, weanling piglets
Performance of lambs fed either hay or silage supplemented with canola or fish meals
Authors: Agbossamey Y. R. , Petit H. V. , Seoane J. R. , St-Laurent G. J.
Published: March 2010

Forty-eight lambs (29.0 ± 4.7 kg BW) were used to study the effects of protein supplementation of forages on performance and diet digestibility. Lambs were fed grass hay or silage ad libitum plus a daily supplement of either: C, a control supplement supplying 1.2 g kg−1 BW of dry molasses and 0.6 g kg−1 BW of minerals, vitamins and lasalocid; CM, control supplement + 5.48 g kg−1 BW of canola meal; or FM, control supplement + 3 g kg−1 BW of fish meal. Apparent digestibility of all dietary components was higher in lambs fed silage than in those fed hay (P < 0.04). Addition of CM or FM improved apparent digestibility of energy and crude protein (CP) of lambs fed hay (P < 0.02) and CP digestibility of lambs fed silage (P < 0.01). Apparent digestibility of CP was higher in lambs fed FM than in those fed CM with either hay or silage (P < 0.03). Addition of CM or FM tended to decrease ADF digestibility of silage-based diets (P < 0.06). Apparent ADF digestibility of hay-based diets was lower in lambs fed CM than in those fed FM (P < 0.02). Forage DM intake was similar for all treatments. Addition of CM or FM to the diets improved average daily gains by 24% (P < 0.03), an effect that was higher with hay (35.1%, P < 0.02). Feed efficiency was 23.6% better in lambs fed protein-supplemented hay than in those receiving C (P < 0.04). Neither dressing percentage nor carcass lean yield was affected by protein supplementation. Digestible DM and TDN intakes were higher in lambs fed silage (P < 0.03) as a result of higher apparent digestibility for silage than hay. Furthermore, CM increased TDN intake by 7.6 and 8.2% in lambs fed hay and silage, respectively, compared with lambs fed FM. Addition of canola and fish meals improved forage nutritive value for lambs. Key words: Canola meal, fish meal, forages, digestibility, lambs, growth
The use of infrared thermography to assess inflammation associated with hot-iron and freeze branding in cattle
Authors: Schwartzkopf-Genswein K. S. , Stookey J. M.
Published: March 2010

Infrared thermography was used to compare differences in extent and duration of inflammation observed on hot-iron and freeze brand sites as an indicator of tissue damage and the associated discomfort to the animals. Thirty beef heifers of mixed breed were assigned to either hot-iron (H) or freeze (F) branding treatments according to a predetermined randomized branding order. Ten animals were branded each day over a 3-d period. On the day prior to branding, animals were clipped to expose two patches of skin; one to be used for the branding treatment and the other for a control. Thermographic images of control and treatment sites were made at 0.08 h (5 min) prior to branding, immediately after the brand was completed (0 h), as well as 0.08, 2, 4, 8, 12, 24, 48, 72, 96, 120, 144 and 168 h after branding. Control site temperatures were subtracted from treatment site temperatures for each individual animal. Both F and H brand sites were consistently warmer (1.9 ± 0.3 and 1.6 ± 0.3 °C, respectively) than their corresponding control sites between 2 and 168 h after branding. Treatment differences were obtained at 0, 0.08, 2, 8, and 144 h after branding (P < 0.001, 0.05, 0.005, 0.001, and 0.01, respectively). Freeze brand sites were warmer at 2 and 8 h after branding while H sites were warmer at 144 h after branding. The thermographic evaluation of hot-iron and freeze brand sites indicated that both methods caused tissue damage. However, H brand sites remained significantly warmer than F sites at 168 h after branding. In addition, H sites were significantly warmer than control sites while F sites were not warmer than control sites at 168 h. The prolonged inflammatory response observed in H animals indicates that more tissue damage and perhaps more discomfort are associated with H branding. Key words: Thermography, branding, cattle, animal welfare, pain.
Current understanding of the role of the reticulum and reticulo-omasal orifice in the control of digesta passage from the ruminoreticulum of sheep and cattle
Authors: Okine E. K. , Mathison G. W. , Kaske M. , Kennelly J. J. , Christopherson R. J.
Published: March 2010

Simultaneous abolition of the motility of the ruminoreticulum (RR) and digesta passage from the RR by bilateral vagotomy indicate that the motility of the RR coordinated with quiescence of the reticulo-omasal orifice (ROO) are prerequisite for caudal movement of digesta from the RR and forestomach. Rate of passage is of importance in ruminant animals since it is related to maximal voluntary feed intake, extent of digestion of the diet, amount of protein which bypasses the rumen, efficiency of microbial growth, extent of methane loss, and susceptibility of animals to bloat. In a series of studies, we clarified the roles of frequency, pressure and duration of reticular contractions and the function of the ROO in controlling digesta flow from the rumen in response to changes in diets, environmental conditions and physiological status. Variability in amount of NDF and OM transferred per contraction suggests that frequency of reticular contraction is not the rate-limiting step in digesta passage from the rumen. This concept is supported by our finding that the relaxation of the ROO is not always coincidental with reticular electromyographic activity in solid meal-fed relative to milk fed sheep. The magnitude of reticular pressure may not precisely control digesta passage through the ROO as the amount of OM and NDF associated with each centimetre of pressure during contraction varies from 1.2 to 1.4 and from 0.9 to 2.5 g. On the other hand, the amount of OM and NDF passed per second of reticulum contraction varies only from 0.3 to 0.6 and from 0.2 to 0.3 g, respectively, in cattle. In addition, a 38% decrease in mean retention time of particulate matter in the rumen was associated with a 14% increase in duration of reticular contraction in cattle. Similarly, quiescence of the ROO increased from 2.9 to 3.3 s in sheep when feed intake increased from maintenance to twice maintenance. We suggest that duration of reticular contractions may be more closely related to digesta flow than is either frequency or pressure changes. We also suggest that the ruminant animal can influence reticular contraction characteristics and duration of the quiescence of the ROO in response to various stimuli and that reticular contractions are coordinated with other diet and physiological demands for optimal transfer efficiency of digesta from the RR. Key words: Digesta passage, reticular contractions, reticulo-omasal orifice, electromyographic activity
Net energy value of timothy and bromegrass silages for beef cattle
Authors: Ouellet D. R. , Seoane J. R. , Lapierre H. , Flipot P. , Bernier J. F.
Published: March 2010

Metabolizable energy (ME), net energy for maintenance and net energy for growth of grass silages were evaluated by the comparative slaughter technique using a 2 × 2 × 3 factorial design. Sixty medium frame beef steers (259 ± 29 kg BW) were divided in groups of five and fed during 3 months either Timothy (T) or Bromegrass (B) harvested at stem elongation (S) of the first cut or at boot stage of the aftermath (A). Forages were fed at one of three levels of intake: ad libitum (FF), 80% of FF, or 65% of FF. Silages averaged 26.9% DM, 16.0% CP and 37.7% ADF. Regression of logarithm of heat production (HE) against ME intake were similar for all silages (log HE = 0.00046*ME + 2.4923; r2 = 0.89). From this equation, fasting HE of 311 kJ kg−0.75 d−1, ME for maintenance of 559 kJ kg−0.75 d−1 and efficiency of utilization of energy for maintenance of 56% were determined. Regression of ME intake against retained energy (RE) were similar for all silages. Efficiency of ME utilization for growth was 33% using the regression of ME over RE with a ME requirement for maintenance fixed at 559 kJ kg−0.75 d−1. Net energy for maintenance and growth were similar for all silages, averaging 6.17 and 3.70 MJ kg−1, respectively. The use of a prediction equation based on ADF of forages underestimated ME values of silages by approximately 25%. Moreover, NRC (1984) equations that estimate NE from experimentally estimated ME values tended to overestimate the net energy of our grass silages. Key words: Net energy, grass silages, timothy, bromegrass, beef cattle
An evaluation of a terminal sire line for feedlot performance, carcass composition, and meat quality
Authors: Sather A. P. , Robertson W. M. , Jones S. D. M. , Zawadski S. M.
Published: March 2010

Three QM Hamline™ (HL; National Pig Development, Canada), four pure-bred Landrace (LR) and Large White (LW) sires were bred to 12, 18 and 8 Manor Hybrid™ (National Pig Development, Canada) sows, respectively, which provided 37 NN-, and 37 Nn- HL, 39 NN- and 37 Nn- LR and 34 NN- LW commercial pigs for a study on the effect of breed of sire and genotype at the halothane locus on pig performance, carcass yield and meat quality. Four pigs per pen, within breed of sire and genotype, were placed on performance test at 56 d of age until total pen weight was 440 kg. Large White, LR and HL NN-pigs were slaughtered at 178, 172 and 177 d of age, adjusted to 110 kg, while LR and HL Nn-pigs were slaughtered at 177 and 178 d of age. HL pigs had 12.7 mm backfat and 44.5 mm of muscle depth at the grade site, while LW and LR had greater backfat thickness (15.1 and 15.7 mm), and less muscle depth (41.1 and 38.7 mm). The halothane genotype did not affect live animal measurements. Feed utilisation was similar in all five groups of pigs. Lean yield of the HL NN-pigs (58.8%) was greater than that found in the NN-LW (56.6%) and NN-LR (56.8%) while the halothane gene made only modest improvement in lean yield in the leaner HL (P = 0.0789) and a more substantial improvement was observed in the fatter LR (P = 0.0161). Total dissected lean was 613, 596, and 639 g kg−1 in LW, LR and HL NN-pigs, respectively, while this increased to 611 and 649 g kg−1 in LR and HL Nn-pigs. QM Hamline™ NN-pigs had larger commercial hams (9878 g) compared with NN-LW and NN-LR sired pigs. Furthermore, they also had greater lean yield in all four lean cuts. The halothane gene had no consistent effect on carcass merit. While initial pH was similar (6.03–6.04) in the three NN-groups of pigs, it dropped to 5.73 and 5.84, among the Nn-LR and HL pigs. Luminosity (59.2%, 58.7%) and hue angle (31.1°, 30.5°) of Nn-LR and HL were higher, with greater drip (5.8%, 5.3%) losses and lower soluble protein (130, 148 g kg−1), compared with NN-LR (54.8%, 24.4°, 3.0%, 185 g kg−1) and HL (55.3%, 26.1°, 3.4%, 182 g kg−1) pigs, respectively. This study indicates carcass merit can be substantially improved without use of the halothane gene and without serious effects to meat quality. However, introduction of the halothane gene can seriously compromise meat quality. Key words: Large White, Landrace, Hamline, halothane gene
Effect of micronization on energy, starch and amino acid digestibility in hulless barley for young pigs
Authors: Huang S. X. , Sauer W. C. , Pickard M. , Li S. , Hardin R. T.
Published: March 2010

Studies were carried out to determine the effect of micronization on energy, starch and amino acid digestibilities in hulless barley. Six pigs (Canabrid × Camborough) were weaned at 21 d of age and fitted with a simple T-cannula at the distal ileum on days 23 or 24. The pigs were fed one of three diets with major constituents of hulless barley and soybean meal (HB + SBM), micronized hulless barley and soybean meal (MHB + SBM) and corn starch and soybean meal (C + SBM) according to a repeated Latin square design. The pigs were fed three times daily, equal amounts at 8-h intervals. The diets were supplied at a rate of 5% (wt/wt) of body weight. The average body weight of the pigs was 9.3 kg at start and 15.9 kg at the conclusion of the experiment at 58 d of age. Faeces were collected for 48 h on days 6 and 7 and ileal digesta for 24 h on days 8 and 9. Chromic oxide was used as digestibility marker. The apparent ileal amino acid digestibilities in HB and MHB were determined by the difference method. The apparent ileal digestibilities of the indispensable amino acids were higher in MHB than in HB and ranged from 5.3 to 10.0 percentage units. Of the indispensable amino acids, the differences were significant (P < 0.05) for arginine, histidine, isoleucine, phenylalanine and valine. Micronization of HB improved (P < 0.05) the ileal digestibility of starch from 79.0 to 97.3%. Micronization resulted in an increase in the digestion of energy in the small intestine and a decrease in microbial fermentation of energy in the large intestine. This shift in the disappearance of energy from the large to the small intestine should also result in an improvement in the efficiency of energy utilization. These studies show a positive effect of micronization on the digestibilities of energy and amino acids in young pigs fed HB. Key words: Micronization, barley, digestibility, pigs
The effects of lighting program, ingredient particle size and feed form on the performance of broiler turkeys
Authors: Hamilton R. M. G. , Kennie J.
Published: March 2010

Two experiments were done to examine the effects of lighting program, ingredient particle size and feed form on the performance of female and male medium White turkey broilers. The poults (1200 initially of each sex) were randomly assigned, within sexes, among 48 floor pens (4.83 × 2.95 m; initially 50 birds each) located in a light-tight house. The treatments were distributed among the pens according to a 3 × 2 × 4 factorial arrangement that contained three lighting programs (four cycles daily of 4L:2D [INT]; 6L:18D at 3 d gradually increasing to 22L:2D at 77 d [INC]; and INC with a 1-h light at the mid-point of the dark period [INC + 1]) and four feed forms (fine mash [FM], FM pelleted [FMP]; course mash [CM]; and CM pelleted [CMP]). The FM was produced by grinding the dietary corn and wheat through hammer mills that contained 3.2- and 4.0-mm screens, respectively, and the CM by grinding the corn in a hammer mill (5.6-mm screen) and passing the wheat through a roller mill in which the spacing between the rollers was about 1.6 mm. All poults received 24L:0D for the first 72 h after housing. Feed and water were provided ad libitum over the 84-d experimental period. During the starter period, the pelleted feeds (FMP and CMP) were crumbled.Turkeys subjected to the INT lighting program had higher body weight gains (P < 0.001), feed intakes (P < 0.001 − 0.05) and mortality (P > 0.05) than the birds under the INC and INC + 1 schedules, but the feed conversions were similar (P > 0.05) for the birds under the three lighting programs. Economic returns from the turkeys subjected to the INC program were higher (P < 0.05) than from those under the other two programs. Body weight gains and feed intakes were higher (P < 0.001 − 0.05) for the birds given the mash feed (FM and CM) than for those fed pellets (FMP and CMP), even though feed conversions were better (P < 0.001) for the turkeys receiving the pelleted feeds. Economic returns were highest for the turkeys fed the CM feeds and lowest for those given the FM feeds; the difference was 3.3%. In conclusion, both lighting program and feed form influenced the economics obtained for broiler turkeys, but fineness of grind had little effect. Key words: Particle size, feed form, lighting program, turkeys, performance
In situ amino acid disappearance from regular, low and high fiber canola meal
Authors: Mustafa A. F. , McKinnon J. J. , Christensen D. A.
Published: March 2010

In situ rumen disappearance of low and high fiber canola meal relative to regular canola meal was determined following 12 h of rumen incubation. In situ amino acid disappearance was similar in low and high fiber and regular canola meal except for threonine and glutamate which was lower (P < 0.05) in high fiber canola meal. It was concluded that ruminal disappearance of amino acids was similar across the three meal types. Key words: Tail-end dehulling, canola meal, high fiber canola meal, low fiber canola meal