bluuebunny/crossref_metadata_2025 huggingface dataset:
Broiler breeder egg production and quality are affected by timing of increased dietary Ca relative to photostimulation
Authors: Petruk and D. R. Korver A.
Published: April 2011

Ross 508 broiler breeder pullets (n = 400) were reared in floor pens in a light-tight facility with feed allocation based on breeder-recommended body weight targets. At 17 wk, 250 pullets within 15% of the mean weight were randomly assigned to individual cages in one of two environmentally controlled environments: 18°C (exp. 1, n = 125) or 28°C (exp. 2, n = 125). The pullets were photostimulated at 20 wk of age. At 2-wk intervals from 18 to 26 wk, successive groups of hens (n = 25 per environment) were switched from a 0.88% Ca grower diet to a 2.96% Ca breeder diet. Dietary treatment names were based on the time (in weeks) relative to photostimulation that the diet was changed from the grower to the breeder diet (PS – 2, PS, PS + 2, PS+4, and PS + 6, respectively). The hens were killed at 31 wk of age and one leg from each hen was taken for bone mineral analysis. The birds in both experiments maintained target body weights as recommended by the primary breeder; however, the hens in exp. 2 did not consume the allotted feed for the final 2 wk of the experiment. Dietary treatment did not affect feed consumption or body weight. Overall percent hen day production was not affected by dietary treatment in either experiment. In exp. 1, hens in the PS + 4 and PS + 6 treatments produced larger eggs and hens in the PS + 4 treatment produced eggs with greater shell weights. Shell weight as a percentage of egg weight was significantly lower from the PS + 6 hens than the other dietary treatment groups. The PS + 4 treatment resulted in the highest bone Ca as a percentage of ash weight, indicating that changing the diet 4 wk after photostimulation was the optimal time to increase bone Ca reserves in that environment. In exp. 2, the PS + 6 treatment had the highest egg weight whereas birds in the PS and PS + 2 treatment groups had the highest shell weights. Percent shell was the lowest in the PS + 6 and PS + 4 treatment groups overall, although it was only significantly different until 27.4 wk of age. Ca as a percentage of bone weight was lowest in the PS + 2 and PS + 6 treatment groups and Ca as a percentage of ash was lowest in the PS + 2 treatment group. Overall, the results suggest that improper timing of increasing dietary Ca either before or too long after photostimulation decreased eggshell quality and bone characteristics. Elevated environmental temperature appeared to exacerbate these effects; therefore, the change from a low-Ca grower to a high-Ca breeder diet must be made with greater precision in hot climates. Key words: Broiler breeder, photostimulation, dietary calcium, calcium metabolism, heat stress
Methane emissions by Charolais cows grazing a monospecific pasture of timothy at four stages of maturity
Authors: Pinares-Patiño C. S. , Baumont R. , Martin C.
Published: April 2011

In order to examine the relationship between herbage maturity and methane (CH4) emission under conditions which minimized opportunities for selective grazing, six 8-yr-old, dry and early-pregnant Charolais cows [712 ± 22.7 kg liveweight (LW)] were grazed on a mono-specific pasture of timothy at four stages of maturity: early vegetative, heading, flowering, and senescence. Daily CH4 production was measured during 7 d using the sulfur hexafluoride (SF6) tracer-gas technique. Organic matter intake (OMI) was determined from fecal output estimated by Yb2O3 dosing and feed digestibility (OMD) estimated using a fecal N index. The OMD (%) decreased (P < 0.05) from 77.6 at early vegetative to 56.2 at senescence, but no cow effect upon OMD was observed. The OMI (14.8 g kg-1 LW) and CH4 production (273 g d-1) were higher (P < 0.05) at heading than at the other stages of maturity. The proportion of gross energy intake (GEI) lost in CH4 did not differ with maturity (mean 6.4% of GEI). Cow effects upon OMI and CH4 emission were significant (P < 0.05). CH4 production (g d-1) was not related to diet chemical composition or OMD, but was correlated with digestible neutral detergent fiber (NDF) intake (kg d-1) (r = 0.61, P < 0.01). Across all stages of maturity between-cow variation explained 54 to 70% of the total variation in CH4 production. Key words: Methane, cattle, animal variation, timothy, phenology, selective grazing
GnRH receptor messenger ribonucleic acid expression in bovine ovary
Authors: Ramakrishnappa N. , Giritharan G. , Aalli M. , Madan P. , Rajamahendran R.
Published: April 2011

The present study was undertaken to investigate the mRNA expression for gonadotropin-releasing hormone (GnRH) receptor in bovine ovary. Granulosa cells from small (< 4 mM), medium (5–8 mM) and large follicles (> 8 mM) and tissues from corpora lutea (CL) of different stages: Stage I (days 1–4), Stage II (days 5–10), Stage III (days 11–17), and Stage IV (days 18–21, days after ovulation) were harvested from bovine ovaries collected at a local abattoir. The mRNA isolated from representative samples was subjected to reverse transcription-polymerase chain reaction (RT-PCR) using gene sequence specific primers. The resultant PCR amplified gonadotropin-releasing horm one receptor (GnRH-R) cDNA products were identified and confirmed through Southern blot hybridization and nucleotide sequence analysis, respectively. The results showed the presence of GnRH-R mRNA transcripts in both follicles and CL. Key words: Bovine, granulosa cells, corpus luteum, GnRH receptor, mRNA
Frequency of concentrate supplementation for cattle fed barley straw. 1. Effect on voluntary intake, ruminal straw disappearance, apparent digestibility and heat production
Authors: Tellier R. C. , Mathison G. W. , Okine E. K. , McCartney D. , Soofi-Siawash R.
Published: April 2011

Five ruminally cannulated crossbred steers (474 ± 30 kg) were fed diets containing 70% barley straw and 30% concentrate in an unbalanced 5 × 5 Latin square design experiment to investigate the effects of frequency of feeding barley grain-based concentrates (daily, alternate days or every third day) with different dietary protein (7.9 and 11.5%) on voluntary intake of straw, ruminal disappearance of straw, apparent digestibility, and heat production. Neither frequency of feeding nor dietary protein concentration influenced voluntary intake of straw, nor did cattle eat differing amounts of straw on days when concentrate was fed in comparison with days when concentrate was not fed. Protein supplementation increased (P < 0.01) 24-h ruminal straw disappearance, but did not affect disappearances at other times. Concentrate feeding frequency had no influence on rate of ruminal disappearance of straw. Apparent digestibilities of dry matter, gross energy, acid detergent fibre (ADF) and crude protein were 5, 6, 8 and 33% higher (P < 0.05), respectively, in diets containing the high-protein concentrate, but were not affected by frequency of concentrate feeding. Heat production (kJ kg-0.75) tended to be reduced (P = 0.06) by 4% in steers fed concentrate on alternate days in comparison with steers fed concentrate daily. Dietary protein concentration had no influence on heat production even though digestible energy intake was 10% higher when the high protein concentrate diet was fed. It was concluded that concentrate can be fed every second day without any negative impact on intake and digestibility, with a possible benefit of a reduction in energy lost as heat. More research, however, is required to study the feasibility of feeding concentrate every third day. Key words: Cattle, straw, protein, feeding frequency, digestion, heat production
The effect of herbage mixtures of alfalfa and orchardgrass on the incidence of bloat in cattle
Authors: Majak W. , Garland G. J. , Lysyk T. J.
Published: April 2011

Alfalfa herbage at the vegetative to early-bud stage of growth was simultaneously fed to cattle with alfalfa- grass mixtures containing 25, 40 or 50% orchardgrass. At all three levels of orchardgrass, there was either complete prevention of bloat or it was substantially reduced. Alfalfa alone yielded 334 cases of bloat as compared to 25 for the mixtures. During the warmest and driest intervals, bloat was reduced only by one-third when the feed alfalfa contained 25% orchardgrass. Key words: Steers, frothy bloat, Medicago sativa L., Dactylis glomerata L., mixed pastures
Mitigation strategies to reduce enteric methane emissions from dairy cows: Update review
Authors: Boadi D. , Benchaar C. , Chiquette J. , Massé D.
Published: April 2011

Enteric methane (CH4) emission is a major contributor to Canadian greenhouse gas emissions, and also a loss of feed energy during production. The objective of this paper is to provide an update on current management practices and new dietary strategies recently proposed to reduce CH4 emissions from ruminants. Existing mitigation strategies for dairy, e.g., the addition of ionophores, fats, use of high-quality forages, and increased use of grains, have been well researched and applied. These nutritional changes reduce CH4 emissions by manipulating ruminal fermentation, directly inhibiting methanogens and protozoa, or by diverting hydrogen ions away from methanogens. Current literature has identified new CH4 mitigation options. These include the addition of probiotics, acetogens, bacteriocins, archaeal viruses, organic acids, plant extracts (e.g., essential oils) to the diet, as well as immunization, and genetic selection of cows. These new strategies are promising, but more research is needed to validate these approaches and to assess in vivo their effectiveness in reducing CH4 production by dairy cows. It is also important to evaluate CH4 mitigation strategies in terms of the total greenhouse gas budget and to consider the cost associated with the various strategies. More basic understanding of the natural differences in digestion efficiencies among animals as well as a better knowledge of methanogens and their interaction with other organisms in the rumen would enable us to exploit the potential of some of the new CH4 mitigation strategies for dairy cattle production. Key words: Enteric methane, dairy cattle, mitigation
Determining the equivalent phosphorus released by an Escherichia coli-derived phytase in broiler chicks
Authors: Adedokun S. A. , Sands J. S. , Adeola O.
Published: April 2011

Seven-day-old male Ross 308 broiler chicks were used in a 14-d experiment to determine the equivalency value of a new phytase using corn-soybean meal based diets. The experimental diets consisted of positive control (PC) or negative control (NC) diets which were formulated to contain 5.0 or 1.2 g kg-1 non-phytate P, respectively, with a total P of 7.7 or 3.9 g kg-1, respectively; and respective calcium levels of 10.0 or 7.6 g kg-1. The test diets were formulated by the addition of monosodium phosphate (MSP; analyzed to contain 224.0 g kg-1 P) to the NC diet to supply 0.5, 1.0, or 1.5 g of P kg-1 diet, and phytase was added to the NC diet at 500 FTU or 1000 FTU kg-1 at the expense of corn starch. Each diet was randomly assigned to eight cages of four birds each. Body weight gain (BWG) showed both linear and quadratic increase (P < 0.05) with increasing level of dietary P or phytase supplementation (450 to 656 or 603 g, respectively). Feed efficiency (g BWG/g feed intake) increased linearly (P < 0.05) with increase in P or phytase supplementation and quadratic effect to increasing level of phytase (P < 0.05) supplementation (0.699 to 0.793 or 0.758 g, respectively). Percent tibia and toe ash increased linearly (P < 0.05) in response to supplemental P from MSP or phytase supplementation (37.7 and 8 to 47.9 and 10.9 or 45.2 and 10, respectively). Total intestinal tract P and N digestibility increased linearly (P < 0.05) with increasing P supplementation and showed increased (linear and quadratic, P < 0.05) response to phytase. The response variables, BWG, toe and tibia ash, feed intake and final body weight were used for P equivalency calculation. By solving the equated linear regression equations for the supplemental inorganic P intake and supplemental phytase intake for each of the response variables, between 0.930 and 1.101 g of P was released by 1000 FTU of phytase. The results of this study showed that this phytase was efficacious in hydrolyzing phytate P for bone mineralization and growth of broiler chicks. Key words: Chicks, equivalency value, monosodium phosphate, phosphorus, phytase
Voluntary feed intake in growing-finishing pigs: A review of the main determining factors and potential approaches for accurate predictions
Authors: Nyachoti C. M. , Zijlstra R. T. , de Lange C. F. M. , Patience J. F.
Published: April 2011

The ability of pigs to consume sufficient nutrients for optimal performance is an important consideration in commercial pork production. Nutrient intake levels are directly related to voluntary feed intake. Voluntary feed intake in pigs is influenced by several factors including environmental conditions (e.g. thermal and social conditions), animal status (e.g., age and physiological status), and feed and feeding conditions (e.g. bulkiness of the feed and feed form). Although the individual effects of many of these factors on voluntary feed intake have been investigated and quantified, little has been done to characterize their interactive effects. Under commercial conditions, voluntary feed intake is clearly influenced by multiple factors at any one time. Thus, there is a need for a means to accurately quantify voluntary feed intake in pigs as affected by the different interacting factors. Until quantitative effects of these interactions are established it is suggested that feed intake be monitored. This can be achieved by obtaining feed intake on representative groups of pigs. Key words: Voluntary feed intake, pigs, determining factors, prediction equations
Feeding micronized and extruded flaxseed to dairy cows: Effects on digestion and ruminal biohydrogenation of long-chain fatty acids
Authors: Gonthier C. , Mustafa A. F. , Berthiaume R. , Petit H. V. , Ouellet D. R.
Published: April 2011

Four lactating Holstein cows fitted with ruminal and duodenal cannulae were used in a 4 × 4 Latin square study to determine the effects of feeding micronized and extruded flaxseed on ruminal biohydrogenation (BH) and digestibility of fatty acids (FA) in the gastrointestinal tract. Four diets were formulated: a control diet with no flaxseed (C); a raw flaxseed diet (RF); a micronized flaxseed diet (MF); and an extruded flaxseed diet (EF). Flaxseed diets contained 126 g kg-1 flaxseed (dry matter basis). Experimental periods (n = 4) consisted of 21 d of diet adaptation and 7 d of data collection. Flaxseed supplementation increased (P < 0.05) intake of individual long-chain FA, reduced (P < 0.05) ruminal BH of total unsaturated C18, and increased (P < 0.05) duodenal flow of individual long-chain FA except for C18:2. Feeding flaxseed increased (P < 0.05) post-ruminal digestibility of C18:1, C18:2, and C18:3 and total tract digestibility of C16:0, C18:2, C18:3, and of total long-chain FA. Heat treatment had no effect on ruminal BH, duodenal flow and digestibility of unsaturated FA. Ruminal BH of C18:3 was higher (P < 0.05), while the duodenal flow of C18:3 was lower (P < 0.05) for cows fed EF than for those fed MF. Intake and duodenal flow of C16:0 were higher (P < 0.05) for cows fed MF relative to those fed EF. It was concluded that inclusion of flaxseed in dairy cow diets increased duodenal flow of polyunsaturated FA. However, heat treatments were not effective in protecting unsaturated FA from ruminal BH. Key words: Flaxseed, ruminal biohydrogenation, fatty acid, heat treatment
Genetic parameters among growth and carcass traits of Canadian Charolais cattle
Authors: Crews D. H. , Lowerison Jr., M. , Caron N. , Kemp R. A.
Published: April 2011

Genetic parameters for three growth and five carcass traits were estimated for Charolais using a combination of carcass progeny test, purebred field performance and pedigree data. Heritabilities and genetic and residual correlations were derived from variance components for birth weight (BWT, n = 54 221), 205-d weaning weight (WT205, n = 31 384), postweaning gain (PWG, n = 19 403), hot carcass weight (HCW, n = 6958), average subcutaneous fat thickness (FAT, n = 6866), longissimus muscle area (REA, n = 6863), marbling score (MAR, n = 6903) and estimated carcass lean yield percentage (PLY, n = 6852) with an animal model (n = 78 728) and restricted maximum likelihood. Breed of dam and contemporary group appropriate to each trait were included as fixed effects in the model, whereas random effects included direct genetic for all traits, maternal genetic for BWT and WT205, and maternal permanent environmental for WT205. Carcass traits were adjusted to a constant harvest age of 425 d. Heritability estimates of 0.53, 0.22, and 0.21 were obtained for direct components of BWT, WT205, and PWG, respectively, and maternal heritabilities were 0.16 and 0.10 for BWT and WT205, respectively. Direct × maternal genetic correlations for BWT (-0.49) and WT205 (-0.35) were negative. Heritabilities for HCW, FAT, REA, MAR, and PLY were 0.33, 0.39, 0.43, 0.34, and 0.46, respectively. Genetic correlations among direct effects for growth traits were moderately positive and generally uncorrelated with maternal effects across traits. Lean and fat deposition in the carcass generally had negative, unfavorable genetic correlations, although improvement in lean yield and marbling score may not be strongly antagonistic. Genetic correlations of direct and maternal components of growth traits with carcass traits suggested that selection for increased growth rate would not be antagonistic to improvement in carcass yield or meat quality. Key words: Carcass, Charolais, correlation, genetic parameters, growth
Bone breakage in three strains of end-of-lay hens
Authors: Budgell K. L. , Silversides F. G.
Published: April 2011

Spent hens of two commercial lines and one heritage line of layers were slaughtered at 72 wk of age and dissected to determine the number of bone fractures before shipping, during depopulation and shipping, and during slaughter. The ISA-Brown and Babcock B300 hens had higher incidences of old (11.1 and 11.7%) and shipping breaks (7.9 and 10.0%) than a line of Brown Leghorns (0.0 and 3.5%, respectively), suggesting that selection of commercial layers for increased egg production may have affected bone strength. All hens experienced broken bones during processing. Key words: Layers, strain, bone breakage
Dietary urea concentration and acid-base balance in feedlot steers fed a high concentrate steam-flaked corn-based diet
Authors: Bailey C. R. , Duff G. C. , Cheatham R. C. , Sanders S. R. , Whitney T. W. , Mendivil O. B. , Treichel J. L.
Published: April 2011

This experiment investigated the effects of dietary urea fed at 0, 0.5, 1.0 or 1.5% [dry mater (DM) basis] of the diet on systemic acid-base balance in feedlot steers. Results indicated that increasing urea concentrations in feedlot diets had no effect on arterial pH, blood gas profile, serum urea nitrogen, or urine pH. Key words: Acid-base balance, beef cattle, urea
Characterization of useful energy content in swine and poultry feed ingredients
Authors: de Lange C. F. M. , Birkett H.
Published: April 2011

For effective use of feed ingredients in diets for the various classes of animals, it is important that the feeding value of feed ingredients is properly estimated. This applies in particular to the useful or bio-available energy content, as feed energy generally represents the single largest cost-factor in animal production. In spite of their limitations, digestible energy (DE) and metabolizable energy (ME) systems are used widely in North America to estimate the useful or bio-available energy content of feeds and feed ingredients for pigs and poultry, largely because experimental procedures to establish DE and ME values are relatively simple. Some of the limitations of DE and ME systems can be overcome by using empirical net energy (NE) systems, whereby feed or feed ingredient NE content is predicted from digestible nutrient contents. However, empirical NE systems require estimates of the animal’s maintenance NE needs, which cannot be measured directly and have been estimated to vary between 489 and 750 kJ kg-1 BW0.60. Moreover, estimated feed or feed ingredient NE contents only apply to one particular animal state. The practical application of NE prediction equations requires an accurate characterization of nutrient contents and digestibility of feeds and feed ingredients. An accurate and flexible assessment of animal and feed effects on energy utilization requires the use of mathematical models in which transformations and use of dietary nutrients for different body functions are represented. Effective use of such nutrient flow models requires accurate characterization of feeds and feed ingredients and of animals in aspects of nutrient partitioning for the various body functions. This type of model can be used to predict accurately the useful energy supply from feeds and feed ingredients for specific animal states for diet formulation purposes. Nutrient utilization models may be refined to explore additional aspects of nutrient utilization, such as dynamics of nutrient absorption, the utilization of nutrients via alternative and competing metabolic pathways and inter-organ nutrient metabolism. Key words: Digestible energy, energetics, feed ingredients, metabolizable energy, net energy, nutrition, pigs, poultry
Amino acid and energy digestibility in different sources of rice bran for growing pigs
Authors: Kaufmann C. , Sauer W. C. , Cervantes M. , Zhang Y. , He J. , Rademacher M. , Htoo J. K.
Published: April 2011

Studies were carried out to determine the digestibilities of amino acids (AA) and energy in five sources of rice bran (RB). The sources of RB included two that were not further processed, a defatted, an extruded, and an atypical source of RB consisting mainly of starchy endosperm referred to as polish. Six barrows, average initial body weight 36.5 kg, were fitted with a simple T-cannula at the distal ileum, and fed six diets according to a 6 × 6 Latin square design. The five RB-containing diets contained 53.8% corn, 19.9% soybean meal, and 23.1% RB. The basal diet contained 71.0% corn and 26.3% soybean meal. The dietary allowance was provided at a rate of 4% (wt/wt) of the individual body weight determined at the initiation of each experimental period. Each experimental period comprised 11 d. Following a 7-d adaptation period, faeces were collected for 48 h and ileal digesta for 24 h in two 12-h periods. Chromic oxide was used as the digestibility marker. There was considerable variation in AA digestibilities among the RB samples. By aid of the difference method under the dietary conditions specified, the apparent ileal digestibilities of lysine, methionine, threonine, and tryptophan ranged from 62.6 to 82.2, 61.4 to 76.0, 58.4 to 82.8, and 58.8 to 82.6%, respectively. The digestibilities were lowest in the defatted source of RB and highest in polish. Not including polish of which the total tract energy digestibility was 88.2%, the digestibilities of the other samples ranged from 60.5 to 65.8%. A small proportion of the variation in AA digestibility can be attributed to the content of crude protein, fat and ash in RB. Key words: Amino acids, digestibility, energy, pigs, rice bran
A path analysis of the factors associated with seasonal variation of breeding failure in sows
Authors: Anil Sukumarannair S. , Larriestra Alejandro , Deen John , Anil Leena
Published: April 2011

Data pertaining to 868 904 services of sows from 58 Canadian herds for the period 1999 to 2003 were retrieved from the PigCHAMP data share database and subjected to path analysis to evaluate the effect of number of inseminations per service (1 and >1), wean to service interval (WSI ≤ 5 d and > 5 d) and parity (parity 1, parities 2 to 5 and parity > 5) on the seasonality of breeding failure. Population attributable fraction (PAF) was calculated to determine the contribution of each risk factor. Overall breeding failure proportions were 23.5 and 20.9% in summer and other months, respectively. The likelihood of breeding failure was higher when sows were artificially inseminated (AI) only once, and 6 and 5% of breeding failures in the summer and other months, respectively, were attributable to single insemination. The likelihood of breeding failure was 1.5 and 1.4 times higher when WSI was > 5 d in the summer and other months, respectively, and 14% of breeding failure in summer was attributable to increase in WSI in summer, and in other months it accounted for 10%. Parity 1 sows reduced the proportion of breeding failure in the population in months other than summer [odds ratio (OR) 0.78]. Sows of parity 2–5 reduced the proportion of breeding failure in both seasons (OR 0.81 and 0.78 in summer and other months, respectively). Key words: Sow, season, breeding failure, WSI, frequency of AI
Effect of dietary lutein and flax on performance, egg composition and liver status of laying hens
Authors: Leeson S. , Caston L. , Namkung H.
Published: April 2011

Lutein is considered a protective nutrient against age-related macular degeneration in humans. An experiment was designed to study the long-term effect of feeding lutein in combination with flaxseed on layer performance, egg parameters, and lutein deposition in eggs and tissues. Laying hens were fed diets with 0 or 10% flax supplemented with 0, 125 or 250 ppm lutein for 11 consecutive 28-d periods beginning at 18 wk of age. Early production was reduced (P < 0.01) by feeding diets with 10% flax and when supplemented with 250 ppm lutein. Diet treatments had no effect on feed intake, egg weight or eggshell deformation. Addition of lutein to the diets significantly (P < 0.01) increased yolk color, and lutein content in the egg, liver, and the preen gland. Egg lutein content increased (P < 0.01) from a basal level of 0.10 mg to 1.60 mg 60g-1 egg by addition of lutein to the diet. Liver fat was lower (P < 0.05) in hens fed 10% flaxseed. Liver hemorrhage score was dramatically reduced (P < 0.01) in birds fed lutein. Key words: egg composition, flaxseed, lutein, layers
Effects of allometric space allowance and weight group composition on grower-finisher pigs
Authors: Anil Leena , Anil Sukumarannair S , Deen John
Published: April 2011

The average daily gain (ADG; kg d-1), pen efficiency (PE; kg ADG m-2 floor space) and welfare indicators (injury levels, salivary cortisol concentrations and behaviour) of grower-finisher pigs were evaluated in groups of 19 barrows, at four levels of floor space allowances calculated mathematically (area = k × BW0.667) using a constant k, (with values 0.027, 0.031, 0.034, and 0.037) for a mean final market weight of 116 kg and in two levels of group weight composition (uniform and varying weights – based on uniformity and variation of body weights of pigs within a pen at the beginning of the experiment). The corresponding space allowances (m2 pig-1) at the market weight of 116 kg were 0.64 (SA0.64), 0.74 (SA0.74), 0.81 (SA0.81), and 0.88 (SA0.88). The data were analyzed using repeated measure ANOVAs and independent sample T tests. The pigs in SA0.64 had a lower ADG (0.859 ± 0.017), spent a lower proportion of time lying in preferred areas (55.22 ± 1.644) and had higher total injury scores (4.581 ± 0.139) and higher number of aggressions (1.94 ± 0.286) (P < 0.05 for all) than those in SA0.88 (0.936 ± 0.020; 61.02 ± 1.203; 3.858 ± 0.208; 1.08 ± 0.212, respectively) and SA0.81 (0.916 ± 0.019; 59.77 ± 1.417; 3.855 ± 0.112; 1.24 ± 0.238, respectively). Pigs in SA0.64 had higher (P < 0.05) overall PE (1.344 kg ADG m-2 floor space) than those in SA0.88 (1.063 ± 0.023) SA0.81 (1.131 ± 0.024) and SA0.74 (1.224 ± 0.029) allowance treatments. Pigs in the varying weight group spent a higher (P < 0.05) proportion of time lying in preferred areas (59.73 ± 0.942) than the uniform weight group (57.08 ± 1.078). Pigs in SA0.74 and SA0.64 spent lower proportion of time (P < 0.05) lying isolated (2.76 ± 0.441 and 2.18 ± 0.372, respectively) than pigs in SA0.81 (4.52 ± 0.467). The uniform weight group exhibited more (P < 0.05) exploratory behaviour (8.83 ± 0.448) than the varying weight group (7.25 ± 0.356). On fully slatted floors, space allotted considering the final market weight of barrows corresponding to k values of 0.037 and 0.034 were better (P < 0.05) than 0.027 in terms of growth rate and welfare indicators. Key words: Space allowances, welfare, daily gain, grower-finisher, pig
Addition of white clover to orchardgrass pasture improves the performance of grazing lambs, but not herbage production
Authors: Papadopoulos Y. A. , Charmley E. , McRae K. B. , Farid A. , Price M. A.
Published: April 2011

Two early-maturing cultivars (Juno and Hallmark), three late-maturing orchardgrass cultivars (Sumas, Rideau, and Kay), and a mixture of orchardgrass (Kay) and white clover (Huia) were seeded in a trial with two replicates. Plots were rotationally grazed for 3 successive years after the establishment year by crossbred lambs. Two contrasts were studied: Kay was compared with Kay/Huia and the early-maturing cultivars were compared with the late-maturing cultivars. Dry matter yield was less for the Kay/Huia than Kay in the 3-yr study, crude protein concentration was similar, and nitrate N concentration was less. Concentrations of ADF and NDF were less for Kay/Huia and stocking density was only 78% of that for Kay over the 3 yr. Efficiency of DM utilization for gain averaged 9.6 for Kay/Huia and 11.4 for Kay, but the difference is not significant. Body weight gain for lam bs grazing Kay/Huia was 40% greater than for lambs grazing Kay; gains per hectare were numerically higher, resulting in bigger lambs with more fat cover. There were no differences in DM yield or chemical composition for early- and late-maturing cultivars. Daily gain for lambs grazing early-maturing cultivars tended to be greater, with most of the effect attributed to a response in 1989. Dressed weight, backfat depth relative to dressed weight were all numerically higher for lambs grazing the early-maturing varieties. We conclude that orchardgrass should be seeded with white clover to increase individual animal performance and output of lamb per hectare. Late-maturing cultivars, when planted in monoculture, had no influence on sward productivity, but appeared to offer some advantage for lamb performance. Key words: Grazing, lamb growth, orchardgrass, white clover
Fatty acid composition and conjugated linoleic acid content of intramuscular fat in crossbred cattle with and without Wagyu genetics fed a barley-based diet
Authors: Mir Z. , Paterson L. J. , Mir P. S.
Published: April 2011

Fatty acid composition and conjugated linoleic acid (CLA) content in pars costalis diaphragmatis (PCD) muscle from European and British crossbred (EBC; no Wagyu genetics) and Wagyu crossbred (WC; 75% Wagyu genetics) beef cattle were determined. Conjugated linoleic acid contents of PCD muscle from EBC (1.7 mg CLA g−1 lipid) and WC (1.8 mg CLA g−1 lipid) cattle were similar (P > 0.05), while WC cattle had higher (P < 0.05) CLA content 100 g−1 of beef on a DM basis because the lipid content of meat from WC cattle was greater (P < 0.05) than that from EBC cattle Key words: Conjugated linoleic acid, Wagyu, fatty acids, barley, beef cattle
Performance of lactating dairy cows fed macerated forage conserved as silage and hay
Authors: Wittenberg K. M. , Ingalls J. R. , McCaughey W. P.
Published: April 2011

The effect of forage maceration at harvest on silage characteristics and its effect on lactation performance of Holstein cows were determined. Either a roller conditioner or a prototype forage macerator manufactured by PAMI were used to cut a 25-ha field of alfalfa (Medicago sativa) forage. The harvested forage was wilted and preserved as silage or hay. Maceration of alfalfa forage resulted in a lower crude protein concentration of fresh forage. Silage volatile fatty acid and ethanol concentration and hay and silage nutrient profiles were not affected by harvest methods. Thirty-four Holstein cows (602.9 ± 3.4 kg) in early lactation were used in a 14-wk lactation study. The cows were fed two dietary treatments in the form of a total mixed ration (TMR); one contained roller conditioner-harvested alfalfa silage and hay and the other contained macerator-harvested alfalfa silage and hay. Feed, weighbacks and milk were sampled daily. Daily dry matter intake (21.6 ± 0.5 kg) was not affected by harvest method. Daily milk yield (38.7 ± 0.3 kg) and milk composition were not affected by dietary treatment during the 14-wk lactation trial; however, cows fed the macerated forage as part of a TMR had a 0.23 kg greater daily body weight gain (P < 0.05). Dietary energy input and energy output (total energy in milk, maintenance and body weight change) were not affected by dietary treatment; however, energy contained in body weight change was greater (P < 0.05) in cows fed a TMR containing the macerated forage. Key words: Alfalfa, maceration, milk yield, body weight, forage energy
Effect of delayed wrapping on preservation and quality of whole crop barley forage ensiled as large bales
Authors: Nia S.A. Moshtaghi , Wittenberg K.M.
Published: April 2011

The effects of delayed bale wrapping on fermentation characteristics, preservation and quality of whole barley crop ensiled as large bales (LBS) were examined. Forage was cut at the early milk stage and allowed to wilt over 24-h period to 47% DM. Bales were allocated to one of three treatments requiring that bales be wrapped within 2, 10 and 19 h post-baling. Bales were sampled at baling and on days 1, 2, 3, 6, 9, 13, 17, 29, 64, 92, 252 and 308 post-baling. Bales were weighed prior to being wrapped and when removed from storage to measure DM and nutrient losses during storage. During wrapping, a thermocouple wire was inserted in each bale to monitor bale temperature. Bales wrapped within 2 and 10 h were similar (P > 0.05) for storage temperature, nutrient profile and recovery, and for lactic and volatile fatty acid content. Lactic acid concentrations peaked between 29 and 64 d post-ensiling for bales wrapped 2 and 10 h post-bailing, but did not peak until day 92 for bales wrapped at 19 h post-bailing. Storage temperature of bales wrapped after 2 and 10 h post-bailing did not exceed 30 °C during storage, but bales wrapped 19 h later exceeded 30 °C for the first 19 d during storage. Bales wrapped within 19 h had a lower (P < 0.05) water soluble carbohydrate content and a higher acid detergent insoluble N and ammonia N level compared to 2 and 10 h bales. The pH and 2, 3 butanediol levels were higher (P < 0.01) in 19 h compared to 2 and 10 h bale silage. A 64 d ensiling period was required to achieve minimum pH values in LBS wrapped with 10 h post-baling, the length of time being greater when wrapping was delayed to 19 h post-baling. Results from this study indicate that delaying bale wrapping to the next day resulted in a temperature rise, and poor silage protein quality. Wrapping 2 h post-baling was not an advantage to wrapping 10 h post-baling in whole crop barley ensiled as large bales. Key words: Silage, large bale, whole crop barley, delayed wrapping, ensiling characteristics
Improved beef tenderness using a modified on-line carcass suspension method with, or without low voltage electrical stimulation
Authors: Aalhus J. L. , Larsen I. L. , Dubeski P. L. , Jeremiah L. E.
Published: April 2011

Carcasses from 59 market-ready steers of an estimated Canada 1 yield grade were used to compare the effects on carcass grade and meat quality of modified, on-line, altered suspension (MOLAS), with or without the application of low voltage electrical stimulation (LVES). Due to conformational changes at the grade site, MOLAS negatively affected both yield and quality grades. However, MOLAS did significantly (P < 0.05) reduce shear force in the longissimus thoracis (LT) and longissimus lumborum (LL) muscles (decreases of 0.65 and 2.11 kg, respectively). In the LT, MOLAS and LVES had similar, non-additive effects; a similar proportion of carcass-es (86%) were classified as tender (shears <5.6 kg) compared to controls (CON; 60%). In the LL, MOLAS was more effective than LVES, and combined MOLAS and LVES had the greatest effect. Only 23.3% of CON carcasses were categorized as tender compared to 53.3% for MOLAS, 27.6% for LVES and 89.7% for combined LVES and MOLAS. Consumers were able to discern these differences, rating MOLAS steaks more highly than CON steaks for almost all hedonic and descriptive traits. Despite significant improvements to tenderness the MOLAS procedure had a negative influence on carcass grade due to conformational changes. The present grading system would need to be modified to accurately assess MOLAS carcasses. Key words: Altered suspension, beef tenderness, low voltage electrical stimulation
Responses to selection for growth and backfat in closed nucleus herds of Hampshire and Duroc pigs
Authors: Gibson J. P. , Quinton V. M. , Simedrea P.
Published: April 2011

A herd of purebred Hampshire and a herd of purebred Duroc pigs were created between 1987 and 1989 and subsequently selected on an index of growth rate and backfat from 1989 to 1995. Strict rules were put in place to promote rapid turnover of generations and allow only minimal culling for structural soundness. In 1990, 1991, 1993 and 1994, a number of sows coming from the Hampshire and Duroc selection lines were bred using frozen semen collected from a sample of control boars born in 1988 and 1989. Estimates of genetic trend based on single trait animal model analyses of age at 100 kg and backfat estimated rates of response to selection of approximately –1.4 and –0.4 days and –0.5 and –0.3 mm backfat per annum in Durocs and Hampshires, respectively. These were close to the original predictions based on the index employed for Durocs, but somewhat less than expected for Hampshires. Comparison of progeny of selected versus control boars was consistent with significant selection responses having been achieved, though estimates of the magnitude of the response had high standard errors. During the period of the trial, both the Hampshire and Duroc herds went from slightly below average on the Canadian National Genetic Evaluation Program to become the number one herds within their breed for the sire line index based on backfat and growth. The trial demonstrated that selection indexes based on estimated breeding values can be used effectively to achieve genetic progress. Key words: Pig breeding, selection index, estimated breeding values, selection response
Effect of pre-slaughter overnight feed withdrawal on pig carcass and muscle quality
Authors: Murray A. , Robertson W. , Nattress F. , Fortin A.
Published: April 2011

The effects of three feed withdrawal treatments (unfasted, 15 h overnight fast at the abattoir, 15 h overnight fast at the piggery) and three additional abattoir lairage times (0–1, 2–3 or 4–5 h) on pig carcass and non-carcass body component yields and on muscle quality characteristics were evaluated. Liveweight yield was lower (P < 0.05) for pigs fasted in the abattoir (by 17 g kg–1) and the piggery (by 22 g kg–1) than for unfasted pigs given a 2–5 h abattoir lairage. Of this decrease, 40–50% was attributed to a lower carcass yield, while the remainder was attributed to a decrease in yield of non-carcass components, especially the gastrointestinal tract. Feed withdrawal decreased (P < 0.05) the amount of distension of the intestinal tract, and increased (P < 0.05) the amount of carcass skin damage due to fighting. It had no effect (P > 0.05) on carcass lean yield, amount of shrink during the chilling process, yield of wholesale cuts, yields of dissected lean, fat and bone in the wholesale cuts, or moisture, fat and protein levels in the longissimus thoracis (LT) muscle. The overnight fast had little impact on LT muscle quality with the exception of slight darkening of the colour of muscles of pigs from which feed was withdrawn at the piggery. Feed withdrawal has the potential to reduce the problem of disposal of gut contents and the risk of carcass contamination as a result of nicking the gastrointestinal tract, and to slightly darken muscle tissue without affecting other meat quality traits. These benefits must be balanced against a decreased carcass yield and an increase in skin damage due to fighting. Key words: Feed restriction, fasting, gastrointestinal tract, gut fill, carcass yield, pork quality
Stability of bovine milk progesterone under different storage and thawing conditions
Authors: Lamont A. G. A. , Colazo M. G. , Ambrose D. J.
Published: April 2011

The objectives were to determine the effects of storage temperature (21 or 4°C), a preservative agent (Brotab 10®) (exp. 1), thawing temperature (37, 21, or 4°C), repeated freeze-thaw cycles (exp. 2), and length of storage at -20°C (exp. 3) on the stability of bovine milk progesterone (P4) over an 8-wk period. Whole-milk samples of 19 pregnant dairy cows were analyzed for P4 using an enzymeimmunoassay (Quanticheck®). In exp. 1, mean P4 concentrations declined (P < 0.01) from 0 to 28 d (5.2 ± 0.1 vs. 3.3 ± 0.1 ng mL-1), but not any further at 56 d. However, P4 decline was lower (P < 0.01) at 4°C than at 21°C at 3 and 56 d, respectively (4.3 ± 0.1 and 3.8 ± 0.1 vs. 3.9 ± 0.1 and 3.0 ± 0.1 ng mL-1). Brotab 10® tended (P < 0.08) to reduce P4 decline. In exp. 2, thawing temperature and repeated freeze-thaw cycles, and in exp. 3, the length of storage at -20°C, did not greatly affect P4 stability. Regardless of the temperature, P4 concentrations declined in all experiments by 1.1 ± 0.1 mL-1 in the first 3 to 7 d of storage and remained relatively stable thereafter, except when stored at room temperature in the absence of a preservative agent. In conclusion, P4 in whole-milk samples remained relatively stable for up to 3 d at 21°C and for up to 14 d at 4°C, even in the absence of a preservative agent. For periods longer than 14 d, whole-milk samples are best stored at -20°C for optimum stability of P4. Key words: Milk progesterone, progesterone stability, storage conditions, enzymeimmunoassay
Effects of flaxseed supplementation on endometrial expression of ISG17 and intrauterine prostaglandin concentrations in primiparous dairy cows submitted to GnRH-based synchronized ovulation
Authors: Petit H. V. , Small J. A. , Palin M. F. , Giguère A. , Santos G. T. D.
Published: April 2011

The objective of the experiment was to determine the effects of feeding whole flaxseed on ovarian function and uterine concentration of prostaglandins on the 17th day post-ovulation. Fortyeight primiparous Holstein cows averaging 550 kg of body weight (BW) were allotted at 2 wk postpartum to two groups of 24 animals: a control diet with no added fat (CON) or a diet with 9% whole flaxseed (FLA). At 6 wk postpartum cows were subjected to a Presynch-Ovsynch protocol with and without artificial insemination on day 0. Real-time transrectal ultrasonography and plasma progesterone concentrations were used to evaluate ovarian function. On day 17, uterine flushings and biopsies of uterine endometrium were collected. Synchronized ovulation rates based on low and high plasma progesterone concentrations on days 0 and 7, respectively, were the same for cows fed CON and those fed FLA (87.5 vs. 87.5%). The 13,14-dihydro-15-keto-PGF2α (PGFM) to prostaglandin E metabolite (PGEM) ratio in uterine flush was significantly higher for non-inseminated cows fed CON (32.0) than for non-inseminated cows fed FLA (17.5) and there was no difference between pregnant cows fed CON (12.2) and those fed FLA (12.0). Feeding flaxseed before breeding may contribute to increased fertility by improving uterine conditions for embryo survival. Key words: Flaxseed, dairy cattle, ovarian function, prostaglandins
Methane emissions and digestive physiology of non-lactating dairy cows fed pasture forage
Authors: Pinares-Patiño C. S. , Waghorn G. C. , Machmüller A. , Vlaming B. , Molano G. , Cavanagh A. , Clark H.
Published: April 2011

The objective of this study was to identify intake and digestion characteristic(s) responsible for variation in methane (CH4) emissions from non-lactating cows fed pasture forage. Nine Friesian × Jersey cows ranked low, medium or high CH4 emitters [group means 15.3, 19.2 and 24.8 g kg-1 dry matter intake (DMI), respectively; P = 0.015] were selected from a herd of 302 lactating cows. The selected cows were dried-off, rumen-fistulated, and fed indoors on fresh pasture forage at 0700 and 1700. Voluntary feed intake (VFI), feeding behaviour and intake rates (IR) were measured over 5 d. Feed allowance was reduced to 90% of VFI for measurement of CH4 emissions and rumen fermentation and digestion kinetics parameters. Although some variation in CH4 yield remained among the animals (26.4 ± 3.6 g kg-1 DMI), the previous ranking of cows during lactation was no longer evident during this study (P = 0.41). The change in CH4 yields may have resulted from lower feed intakes of lower quality pasture compared with grazing. Regression analysis showed that absolute CH4 emission (g d-1) was best described by DMI and rumen acetate concentration (ACE) before the PM feeding (ACE 1700) (R2 = 0.88), whereas CH4 yield (g kg-1DMI) was mainly a function of ACE 1700 h alone (R2 = 0.84). We suggest that large animal-to-animal variations in CH4 yield are most likely associated with high intakes and concomitant effects of salivation and rumen digestion and passage. Key words: Methane, animal variation, feed intake, rumen digestion, dairy cows, pasture
Chemical composition, ensiling characteristics and ruminal degradability of forage soybean cultivars
Authors: Mustafa A. F. , García J. C. F. , Seguin P. , Marois-Mainguy O.
Published: April 2011

A study was conducted to determine the effects of forage soybean cultivar on chemical composition, ensiling characteristics, and ruminal degradability of silage. Two cultivars of forage soybean (Kodiak and Mammouth) were field-grown, harvested at the R6 stage, and ensiled in mini-silos (n = 3) for 0, 2, 4, 8, 16 and 45 d. Two ruminally fistulated cows were used to determine in situ ruminal nutrient degradabilities of the 45-d silages. Both cultivars went through slow fermentation as indicated by a gradual decline in pH up to day 45 post-ensiling. Lactic acid concentration increased throughout ensiling and was higher for Mammouth than Kodiak except at day 45 post-ensiling. Analysis of the 45-d silages showed that Mammouth contained higher neutral detergent fiber (NDF, 490 vs. 444 g kg-1), acid detergent fiber (371 vs. 353 g kg-1) and acid detergent lignin (81 vs. 64 g kg-1) than Kodiak. However, crude protein (CP) concentration was higher for Kodiak than Mammouth. Mammouth silage had lower buffer soluble protein and higher neutral and acid detergent insoluble protein concentrations than Kodiak silage. Results of the in situ study indicated that Kodiak silage had greater ruminal dry matter (606 vs. 549 g kg-1), CP (828 vs. 752 g kg -1) and NDF (272 vs. 227 g kg-1) degradabilities than Mammouth. It was concluded that chemical composition and ruminal nutrient degradabilities of forage soybean silage were significantly influenced by cultivar. Key words: Soybean [Glycine max (L.) Merill.], silage, ensiling; forage quality, nutrient degradability