Livestock Science

Published by Elsevier BV

Print ISSN: 1871-1413

Articles


Relationship between the expression of key lipogenic enzymes, fatty acid composition, and intramuscular fat content of Limousin and Aberdeen Angus cattle
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January 2010

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110 Reads

Rebecca E. Ward

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The amount and fatty acid composition of intramuscular fat (IMF) are major factors in determining the nutritional value of beef. Understanding the mechanisms regulating IMF formation is important for designing strategies for manipulation of IMF quantity and quality. The aim of this study was to investigate the contribution of key lipogenic enzymes towards intramuscular fat formation in Aberdeen Angus and Limousin crossbred steers. This study reports the presence of 150 kDa acetyl-CoA-carboxylase α (ACCα), 150 kDa fatty acid synthase (FAS), 37 kDa stearoyl-CoA desaturase (SCD), 50 kDa Δ6-desaturase (Δ6d), and 50 kDa Δ5-desaturase (Δ5d) immunoreactive bands in cattle muscle (as detected by Western blot analyses). A significant positive relationship was established between ACCα protein content and IMF content; FAS protein content and IMF, as well as between expression of these enzymes and the products of their reactions, saturated fatty acid. IMF level was also positively related to the expression of Δ6d and Δ5d proteins. However, no relationship was found between IMF and the amount of SCD protein. It is suggested that the rate of saturated fatty acids and PUFA biosynthesis might have a significant impact on IMF deposition in cattle.
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Surgical techniques for quantitative nutrient digestion and absorption studies in the pig
  • Article
  • Full-text available

September 2010

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90 Reads

Surgical techniques allow quantitative measurement of nutrient digestion and absorption in pigs. The present paper presents our updated techniques for anaesthesia and surgery. The surgery technique of catheterization of the portal vein, mesenteric vein and mesenteric artery, as well as the fitting of a flow probe for continuous portal blood flow measurements in sows is described. Further, the cannulation of the terminal ileum with a dirigible bi-directional T-cannula for the total collection of ileal digesta is described.
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Nutritional status, growth performance and carcass characteristics of Nguni steers supplemented with Acacia karroo leaf-meal

December 2009

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363 Reads

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The objectives of the current study were to determine the effect of supplementing Acacia karroo leaf-meal on growth performance, blood chemistry and carcass characteristics of Nguni steers. Thirty 19-month old Nguni steers (241.5 ± 14.62 kg) were randomly allotted to three dietary treatments: A. karroo leaf-meal (AK), sunflower cake (SF) and control with no supplement (CN). Steers on the AK and SF diets were offered additional 150 g of protein through A. karroo and sunflower cake per day for 60 days. Serum concentrations of nutritionally-related blood metabolites were measured every fortnight. Steers that were given supplementary diets had higher (P < 0.05) total protein, urea, non-esterified fatty acids, calcium, phosphorus, magnesium and iron concentrations, and larger eye muscle area than those that received the CN diet. Albumin concentration was higher (P < 0.05) in steers that received supplementary diets than those that did not. Steers supplemented with the AK and SF diets had lower (P < 0.05) glucose and cholesterol concentrations than those that received the CN diet. Steers fed on the SF diet had the highest average daily gain, body condition score, slaughter weight, warm carcass weight and cold carcass weight followed by those on the AK diet (P < 0.05). Steers that were supplemented with AK and SF diets had similar (P > 0.05) gross margins. It was concluded that A. karroo improves the nutritional status, growth performance, and carcass traits of Nguni steers reared on natural pasture.

Dietary supplementation with Acanthopanax senticosus extract enhances gut health in weanling piglets

August 2009

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134 Reads

The present study was conducted to investigate the effects of Acanthopanax senticosus extract (ASE) as a dietary additive on gut health in weanling piglets by examining diarrhea frequency, intestinal microbiota and morphology. A total of 96 Duroc× (Landrace × Yorkshire) piglets weaned at 21 days of age with an average initial body weight (BW) of 5.6 ± 0.4 kg were randomly assigned to 3 treatment groups with 4 duplicates of 8 piglets each. The piglets were fed basal diet to which had been added 0 or 1 g/kg of ASE, or 0.7 g/kg antibiotics, respectively. Fecal consistence was monitored twice daily and the frequency of diarrhea was calculated. On day 21 after the initiation of supplementation, 8 piglets were randomly selected from each treatment group (2 piglets per pen) and slaughtered. The jejunum, ileum, colon and cecum were then excised and fixed in 10% neutral formalin solution to determine villus height and crypt depth, after their contents were collected to determine microbiota. The results showed that dietary supplementation with ASE increased (P < 0.05) the density of bacterial populations that co-migrated with Lactobacillus amylovorus, Lactobacillus salivarius, Bacillus subtilis, and Clostridium lituseburens, but decreased (P < 0.05) those co-migrating with Staphylococcus aureus, Salmonella typhimurium, Ruminococcus forques, and E. coli O157:H7 in the PCR-DGGE profiling analysis when compared with the control group. The villus height of the duodenum, jejunum and ileum increased (P < 0.05) by 14.8, 13.7 and 10.0%, while the crypt depth decreased (P < 0.05) by 17.9, 9.1 and 12.1%, respectively, in response to dietary ASE supplementation. Additionally dietary supplementation with ASE or an antibiotic decreased (P < 0.05) the frequency of diarrhea by 55.6 and 52.2%, respectively, compared with the control group. In conclusion, these findings suggest that dietary supplementation with ASE could regulate the microbiota composition and maintain a normal morphology of gut mucosa in weanling piglets, thereby decreasing diarrhea that resulted from weaning stress.

Developmental changes in clearance of intravenous doses of glucose, acetate and β-hydroxybutyrate from plasma of calves

June 2009

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49 Reads

To characterize the effects of diet and age on the post-absorptive use of fermentation end-products, calves were subjected before and after weaning to plasma glucose, β-hydroxybutyrate and acetate clearance tests. Twenty-four one-week old male Holstein calves were assigned to one of four starter feeds, in a complete random design: (1) control; (2) 10% alfalfa; (3) 20% alfalfa; and (4) cracked corn. Starters were fed ad libitum. Starter intake, carcass-adjusted body weight gain and post-weaning rumen pH were higher in calves consuming alfalfa. Final bodyweights of calves fed alfalfa were 9.5 kg higher than calves given the other diets. With 20% alfalfa, papillae in the caudal ventral blind sac of the rumen were taller than with cracked corn and narrower than on the control. Rumen concentrations of volatile fatty acids were not affected by diet but the acetate:butyrate ratio and pH were higher on d 54 with 20% alfalfa compared to the control. Glucose clearance and flux rates increased significantly from d 11 to 39 but were unaffected to d 53. Increases in plasma β-hydroxybutyrate and acetate concentrations with age were accompanied by corresponding increases in BHB and acetate fluxes, respectively, but no change in the clearance rate constants. There was little effect of diet on clearance of the plasma metabolites. By 8 weeks of age, glucose was cleared from plasma at 2%/min, β-hydroxybutyrate at 16%/min, and acetate at 24%/min. Because of relatively low plasma concentrations of β-hydroxybutyrate and acetate due to incomplete rumen development, glucose remained the predominant energy source for all calves at 8 weeks.

Feeding organic acids enhances the barrier function against pathogenic bacteria of the piglet stomach

May 2007

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125 Reads

The effect of coarsely ground meal feed versus finely ground heat-treated pelleted feed and the addition of lactic acid and formic acid in combination on the physico-chemical properties, microbial composition and concentration of organic acids in the stomach content of piglets was investigated. A total of 60 weaned piglets were included in a 2 × 2 factorial arrangement in 15 randomised complete blocks. After three weeks, the pigs were put down and samples of digesta from the gastrointestinal tract were analysed for dry matter (DM), pH, organic acids and microbiological enumeration. Feeding coarsely ground meal feed increased the DM percentage, the concentration of organic acids and pH in the proximal stomach and lowered the distal stomach pH compared with finely ground heat-treated pelleted feed. However, the addition of organic acids to the diets lowered the pH in the stomach and was able to reduce the population of enterobacteria in the stomach.

Table 4
Analysis of fatty acids in Longissimus muscle of steers of different genetic breeds finished in pasture systems

June 2007

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104 Reads

The chemical composition, the fatty acids profile, and conjugated linoleic acids content in Longissimus muscle (LM) of steers have been determined. For such, 18 steers (6, Nellore, NEL) and their Simmental (6, NSI), and Santa Gertrudes (6, NSG) crossbreds finished in pasture system with Brachiaria brizantha cv. marandu for about 3 months with approximate weight at slaughter of 480 kg at average age approximate of 25 months. The lipid content increased in the following order influenced by genetic groups: Nellore, F1 Nellore × Simmental and F1 Nellore × Santa Gertrudes crossbreds. The lipid content increased while moisture, ash and protein contents decreased. The content of saturated fatty acids (SFA) was affected by genetic groups. The conjugated linoleic acids contents (CLA) in fat were similar in the genetic groups, but the quantity of CLA concentrations in muscle lipids of steers with larger total lipid was higher. The predominant CLA was CLA cis-9, trans-11.

The Global Plan of Action for Animal Genetic Resources — The road to common understanding and agreement

March 2011

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135 Reads

The first International Technical Conference on Animal Genetic Resources for Food and Agriculture, organized by the Food and Agriculture Organization of the United Nations, took place from 3 to 7 September, 2007, in Interlaken, Switzerland. The main achievement of the Conference was the adoption of the Global Plan of Action for Animal Genetic Resources, the first ever international framework for the promotion of the wise management of animal genetic resources for food and agriculture, endorsed by governments. The article describes the technical and intergovernmental processes developing the Global Plan of Action. The adoption of the Global Plan of Action has created unprecedented momentum for promoting the sustainable use, development and conservation of the world's livestock diversity. The international community is now facing the challenge to ensure that the Global Plan of Action is effectively implemented.

Effect of banding or burdizzo castration on plasma testosterone, acute-phase proteins, scrotal circumference, growth, and health of bulls

August 2008

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777 Reads

The objective was to assess the effect of banding or burdizzo castration performed on farms on plasma testosterone, acute-phase proteins, scrotal circumferences, growth, and well-being of bulls. 243 Continental bulls (12 months; 399.2 ± 5.72 kg) from three different farms were allocated at random, after stratification on weight within breed type, to one of three treatment groups: banding castration (BAND; n = 80), burdizzo castration (BURD; n = 83), or controls (CON; n = 80). The castration methods were conducted under local anaesthesia, and tetanus toxoid vaccine and antibiotic were also injected at castration. BAND and BURD castrates had lower (P < 0.001) plasma testosterone concentration than control bulls, with no difference between BAND and BURD castrates on 28 d post-castration. From days 0 to 14 post-castration, BAND (P = 0.0002) and BURD (P < 0.0001) castrates had lower average daily gain (ADG) than CON bulls, no difference (P = 0.46) was found between BAND and BURD castrates. From days 15 to 28, BAND castrates had lower ADG compared with BURD castrates (P = 0.03) and CON bulls (P = 0.01), while no difference (P = 0.76) was found between BURD and CON. From days 29 to 56, BAND (P = 0.01) and BURD (P = 0.002) castrates had lower ADG than CON bulls, no difference (P = 0.55) was found between BAND and BURD. From days 57 to 84, the ADG of BAND castrates was not different compared with BURD castrates (P = 0.12) and CON bulls (P = 0.38), while BURD had lower (P = 0.02) ADG compared with CON. The integrated ADG from day 0 to 112 of BAND (P = 0.0001) and BURD (P = 0.02) groups were lower compared with CON, while there was no difference (P = 0.09) between BAND and BURD castrates. On d 14 post-castration, BAND castrates had lower scrotal temperature than BURD (P < 0.0001) and CON (P < 0.0001), and BURD castrates had greater (P < 0.006) scrotal temperature than CON; BAND castrates had lower scrotal latitudinal and longitudinal circumferences than BURD castrates (P < 0.001) and CON bulls (P < 0.001), and BURD castrates had greater (P < 0.001) scrotal latitudinal and longitudinal circumferences than CON bulls. BAND (P < 0.0001) and BURD (P = 0.01) castrates had greater glucose concentration than CON bulls, and BAND castrates had greater (P = 0.04) glucose concentration than BURD. In conclusion, BAND or BURD castration significantly reduced plasma testosterone concentration; reduced average daily weight gain mainly during the first 2 weeks, which was not compensated during the subsequent 16 weeks; increased withdrawal of stored energy and increased plasma protein concentration. BURD showed an advantage over BAND in growth during days 15 to 28 following castration.

Reducing phosphorus concentration in pig diets by adding an environmental objective to the traditional feed formulation algorithm

August 2007

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79 Reads

A multi-objective optimization method based on the traditional least-cost formulation program was developed to reduce both feed cost and total phosphorus (P) content in pig feeds. The objective function of the proposed method comprises a traditional economic term and a term that assigns a cost (β) to the excess and unavailable P (EUP) in the diet, the latter estimated by the difference between P requirements and available P supplied by the diet. To evaluate this method, feeds for growing (20–65 kg live weight) and finishing pigs (65–105 kg) formulated with two balanced protein levels (90 and 130 g/kg) and two available phosphorus levels (3.2 and 2.6 g/kg) were evaluated in two economic contexts (France and Quebec) over a 12-month period (June 2002–May 2003). Microbial phytase was added to the feeds at rates of 0, 250, 500 and 750 phytase units. All feed formulas contained the required available P and other nutrients. The increase in β reduced the total P and EUP in feed formulas. During the period studied, EUP decreased by 5% or more for an increase in feed cost of about 1.5% in France and 1% in Quebec. For some months however, the economically optimal solution was close to a solution that produces substantially less EUP at slightly higher cost. For example, in nearly half of the months, a reduction of 10% or more was achieved in Quebec for the same 1% increase in ingredient cost. The reduction in EUP with increasing β occurred independently of the addition of microbial phytase. The combined effect of microbial phytase incorporation and the proposed feed formulation method on EUP reduction is almost additive. Thus, the combined use of these two techniques can promote the sustainability of the swine industry by contributing to the reduction of P excretion in swine operations with small increases in feeding cost. The proposed method can be applied to minerals other than P or to other livestock production systems in which mineral excretion can be estimated from feed composition.

Effect of prepartum administration of monensin on metabolism of pregnant ewes

February 2011

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137 Reads

A prospective study involving 18 pregnant ewes of Baloochi breed were conducted to measure the effect of monensin administered 40 days pre-lambing on metabolic function pre-parturition and post-parturition. The pregnant ewes were randomly assigned to one of the 4 treatments: 1) were received monensin and fed an ordinary ration, 2) received monensin and fed restricted ration, 3) fed restricted ration without monensin and 4) control group which fed an ordinary ration without monensin administration. Blood was sampled from each sheep at days 60, 45, 30, 20, 15, 10, 5, 1 prior to parturition, and hour 12 and days 1, 2, 3, 4, 7, 13, 19 and 21 postpartum. The BHB concentrations significantly decreased in animals which received monensin and fed a restricted or an ordinary ration in comparison to the group which not received monensin and fed a restricted ration at prepartum period. The sheep which received monensin showed lower concentrations of NEFA in comparison to animals which were not received monensin. There was no significant effect of monensin on energy, protein indicators and electrolytes in postpartum period. However, feed restriction significantly decreased the concentrations of cholesterol, urea, albumin and Mg at post-parturition period. The results of this study indicate that administration of monensin to pregnant ewes during prepartum period had a markedly positive influence on energy indicators in late pregnancy.

Dietary protein level affects in vitro peristaltic reflex in the small intestine of young pigs

May 2007

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24 Reads

The aim of the study was to investigate the effect of dietary protein level on contractility of the small intestine in young pigs. Animals (about 15 kg BW initially) were fed during 40 days with isoenergetic diets containing 16, 18, or 20% of crude protein. Higher protein levels in the diets as well as similar concentration of essential amino acids were attained by substitution of corn starch with wheat gluten and crystalline amino acids. At about 40 kg BW, the animals were sacrificed and the longitudinal strips of duodenum and mid-jejunum were taken for analysis of smooth muscle mechanical activity in vitro. Spontaneous activity, responses to electrical field stimulation (EFS), and responses to acetylcholine (ACh) were recorded. Frequency and amplitude of spontaneous contractions were similar in all groups, both in the duodenum and the mid-jejunum. In the duodenum, responses to EFS and ACh were the same irrespective of the dietary protein level. Responses to EFS in the mid-jejunum were significantly enhanced in the animals receiving the diet with 20% protein; however, the response to ACh was not changed. The mechanism of neuronal response may involve primary afferent pathways “sensing” contents in the lumen of the intestine through enterochromaffin cells. The enteric neuronal pathways may also be activated by a higher level of free amino acid(s) or by dietary peptides and proteins.

The proportion of gleaning leaves and fruits, and browsing leaves and fruits in percentage of the total number of recordings of browsing and gleaning during the study period (LS means and SE).
Behaviour of goats, sheep and cattle on natural pasture in the sub-humid zone of West Africa

December 2006

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424 Reads

The behaviour of sheep, goats and cattle on a shrub and tree savannah in the sub-humid zone of West Africa was studied during the dry (February to May), rainy (June to September) and cool season (October to January). Two mature females per animal species were followed by two observers during 3 days per month and behaviour activities were recorded every 15 min of the daily grazing time. When browsing, the plant name, plant part and plant height reached during prehension were recorded. The distance travelled and the grazing circuits were recorded with a step counter and a Geographic Position System device. The knowledge of farmers concerning appreciated browse species relative to the browse species consumed by animals in the area was also investigated.

Effects of concentrate supplementation on carcass and meat quality attributes of feedlot finished Small East African goats

November 2009

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91 Reads

Effects of concentrate supplementation on carcass and meat quality of feedlot finished Small East African (SEA) goats were assessed using 23 animals (14.5 months old and 20.1 kg body weight). Goats were subjected to four levels of concentrate supplementation: ad libitum concentrate allowance (T100), 66% of ad libitum concentrate allowance (T66), 33% of ad libitum allowance (T33) and no concentrate (T0). All goats were slaughtered after 90 days of experimental period. The ad libitum concentrate intake attained by the goats was about 370 g DM/d. All concentrate-supplemented goats had similar (P > 0.05) total dry matter intake. T100 goats had 31 g and 14 g higher (P < 0.05) daily body weight gain than T33 and T66 goats, respectively. T100 and T66 goats were comparable in final live weight and empty body weight but both were heavier (P < 0.05) than that of T33 and T0 goats. Hot and cold carcass weights for both T100 and T66 goats were 3 kg heavier (P < 0.05) than that of T0 goats. Concentrate-supplemented goats had similar (P > 0.05) EUROP scores for carcass fatness. T100 and T66 goats had 6.5 and 3 units higher (P < 0.05) scores for conformation than T0 and T33 goats, respectively. Dressing percentage increased with levels of concentrate supplementation in a curvilinear fashion, with highest values in T66 goats. At 6 h post-mortem, muscle pH for concentrate-supplemented animals was significantly lower compared with T0 goats. Carcass fat content was 9% higher (P < 0.05) in concentrate-supplemented goats than in their contemporaries. No differences in cooking loss or shear force were observed among treatments, while these variables were affected by the type of muscle. It is concluded that feedlot finishing of SEA had limited effects on meat quality. Finishing SEA goats at 66% of their ad libitum concentrate intake, however, significantly improved weight gains and carcass fatness. Cost–benefit analyses are recommended before embarking on a large scale feedlot finishing of SEA goats.

Table 2 Predicted values of the base scenario (Sc0) and deviations on observed values (%) for each MT.
Simulation of mountain cattle farming systems changes under diverse agricultural policies and off-farm scenarios

May 2011

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177 Reads

European mountain farming systems have changed considerably in recent years. These changes are due to factors related to the following: internal characteristics of the farm and household; local and regional conditions; and economic and political environment that determine the general market situation and subsidies that the farmers receive. The decoupling of subsidies decided in 2003 CAP reform was an unprecedented change that raised many questions about the response of mountain livestock farming systems. The objective of this paper was to analyse the possible adaptation strategies of mountain cattle farms in various scenarios as a result of changes in policies and markets. The study is based on a previous evaluation of cattle farms diversity carried out in three valleys of the Spanish Pyrenees. Six types of farms characterised according to their past observed evolution trajectory (1990 to 2004) (García-Martínez et al., 2009) were the basis to define mixed linear programming (LP) models that represented the annual operation of the farms. Five socioeconomic and policy scenarios were simulated depending on CAP conditions (partial or total decoupling), orientation of production (weaned or fattened calves) and existence of an off-farm work market (tourism activity). Sensitivity analyses for the price of feedstuff cereals, meat and weaned calves were completed. Off-farm work was economically profitable in the majority of the cattle farms under the current situation of partial decoupling, which may lead to a further decrease in the livestock farming activity and changes in land use (less proportion of mowing semi-natural grassland). Calf fattening was a viable activity, but it was extremely sensitive to changes in the prices of inputs and outputs. Therefore, a raise in the price of cereals or a declining price of meat may lead to a drastic decrease in calf fattening. Ensuring the provision of environmental services by mountain agriculture will not only depend on the specific circumstances in which conditionality is applied but also on the amount and delivery conditions of agri-environmental subsidies. In areas where tourism is on the rise, it is likely that the presence of non-agricultural activities on the farms will continue to increase, and, consequently, so will the displacement of the livestock activity with subsequent changes in land use. Furthermore, this trend will be accentuated in times of total decoupling.

Chromatin and morphometry alterations of bovine sperm head after Percoll (TM) density gradient centrifugation

November 2011

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26 Reads

The aim of this work was to assess the morphometry and chromatin integrity of bovine sperm head after a three layers discontinuous Percoll™ density gradient centrifugation. Frozen semen doses were obtained from six bulls of different breeds, including three taurine and three Zebu animals. Three ejaculates per bull were evaluated. The semen doses were thawed and two smears were made from each sample before (control) and after the Percoll™ centrifugation (Percoll™ group). The smears were stained with toluidine blue and grayscale digital images were captured and processed in Scilab environment software. It was observed that chromatin heterogeneity was reduced (P < 0.05) and chromatin decondensation was increased (P < 0.05) after the Percoll™ treatment utilized. In addition, it was observed that sperm head length was higher (P < 0.05) and the side symmetry was lower (P < 0.05) in centrifuged sperm cells. When analyzed separately by subspecies, it was observed that the decrease (P < 0.05) in chromatin heterogeneity and the increase (P < 0.05) in chromatin decondensation occurred in Zebu sperm heads. In addition, the length and the width:length ratio of sperm heads was affected by Percoll™ centrifugation in Zebu semen. In conclusion, the three layers discontinuous Percoll™ centrifugation increased the chromatin decondensation and the morphometric alterations of frozen-thawed bovine semen. However, the real implication of these findings in fertility rates of centrifuged sperm must be investigated.

Evaluation of growth performance of broiler birds fed with diet containing different levels of velvet bean meal as an alternative protein ingredient

January 2010

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96 Reads

The effect of replacement of soybean meal (SBM) by the velvet bean meal (VBM) as an alternative protein ingredient on the growth performance of broiler birds was investigated. The seed materials of velvet bean (VB) [Mucuna pruriens (L.) DC. var. utilis (Wall. ex Wight) Baker ex Burck], an under-utilized food legume collected from South India, was found to contain appreciable levels of proteins (265 g/kg DM); lipid (65.1 g/kg DM); Neutral Detergent Fiber (84.3 g/kg DM) and ash content (49.2 g/kg DM). Soaking in sodium-bi-carbonate solution + autoclaving treatment was found to cause substantial reduction on the levels of antinutritional compounds such as tannins (75%), L-Dopa (81%), phytic acid (70%), raffinose (92%), stachyose (89%), verbascose (71%), haemagglutinating activity (75%), trypsin inhibitor activity (78%) and α-amylase inhibitor activity (77%) without affecting the nutritional quality of VB seeds. Such processed VBM was incorporated as an alternative protein source by replacing the SBM protein at 0, 20, 40, 60, 80 and 100% levels in the commercial type broiler diets. Replacement of SBM up to 40% level with VBM as an alternative protein ingredient in the poultry diet, which corresponds to the inclusion of VBM up to 15.7% in the starter feed and 11% in the finisher phase poultry feed, exhibited better growth performance of the broiler birds without any adverse effects.

of dietary treatment on nitrogen balance and nutrient digestibility coefficients (L.S.M. F S.E.M.) from day 33 to 39
Effect of dietary treatment on daily gain, feed conversion ratio (FCR) and carcass characteristics (L.S.M. F S.E.M.)
The effect of amino acid restriction during the grower phase on compensatory growth, carcass composition and nitrogen utilisation in grower–finisher pigs

October 2006

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116 Reads

Three hundred and ninety six pigs weighing 42 kg (s.d. +/− 2.5 kg), (progeny of Landrace × Large White sows × Meatline boars) (216 boars and 180 females) were assigned to four dietary treatments to determine the effects of restricting dietary lysine during the grower period (approximately 42 to 63 kg) on nitrogen (N) intake, retention and excretion during the finisher period (approximately 63 kg to slaughter at 94 kg). Two experiments, a performance experiment (nine replicates/treatment) and a N balance experiment (four replicates/treatment) were carried out. The experimental treatments were (1) 1.25% lysine from d 0 to d 28 and 1.05% lysine from d 29 to slaughter (HM), (2) 1.05% lysine from d 0 to slaughter (MM), (3) 0.85% lysine from d 0 to d 28 and 1.05% lysine from d 29 to slaughter (LM) and (4) 0.85% lysine from d 0 to slaughter (LL). All diets were pelleted and formulated to contain 13.8 MJ DE/kg. The pigs were group fed in mixed sex pens using single space feeders (11 pigs/feeder, 6 boars and 5 females). In the N balance experiment, sixteen entire male pigs, after 16 days on the diets were placed individually in metabolism crates and urine and faeces were collected. The pigs offered the 0.85% lysine diets during the grower period had a lower average daily gain (ADG) and a poorer feed conversion ratio (FCR) than the pigs offered 1.25% and 1.05% lysine diets (P < 0.05). During the early finisher period (days 29–42) and overall finisher period (days 29–56) pigs on treatment LM had a higher ADG (P < 0.01) and a better FCR (P < 0.05) than pigs on treatment LL. Pigs on treatment LM also had a better FCR than pigs on treatment HM and MM (P < 0.05) during the early finisher period. Pigs on treatment LM had a significantly (P < 0.05) higher lean meat proportion than pigs on treatment LL. During the grower N balance, pigs on the 0.85% lysine diets (treatments LM and LL) had lower N intakes (P < 0.001), N excretions (P < 0.001) and a higher (P < 0.001) nitrogen utilisation than pigs on treatments MM and HM. During the finisher N balance, pigs on treatment LL had a lower N intake (P < 0.001), N excretion (P < 0.01) and N retention (P < 0.05) than pigs on all other treatments. In conclusion, restricting dietary lysine during the grower period reduced growth rate but resulted in a more efficient growth during the early finisher period once dietary lysine was restored.

Methionine: A metabolically unique amino acid

October 2007

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545 Reads

Methionine is a dietary essential amino acid that plays unique roles, both in protein structure and in metabolism. Methionine serves as the initiating amino acid in eukaryotic protein synthesis. In globular proteins, most methionine residues are buried inside the hydrophobic core. Some methionine residues, located on the surfaces of proteins are susceptible to oxidation to methionine sulfoxide. These may be reduced back to methionine by methionine sulfoxide reductase. Methionine's principal metabolic function lies in its conversion to S-adenosylmethionine which is the principal biological methylating agent. Methionine metabolism may be divided into transmethylation, remethylation and transsulfuration. S-adenosylmethionine, via allosteric mechanisms, exerts control over these processes. Creatine synthesis is a major user of S-adenosylmethionine-derived methyl groups. Piglets acquire considerable quantities of creatine during growth. About one third of this is provided in the milk; two thirds is synthesized within the piglet. This requires very high rates of creatine synthesis and has the potential to be a significant drain on dietary methionine.

Application of recombinant antibody library for screening specific antigens in a bovine sperm cell subpopulation

April 2008

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127 Reads

Antibody phage display libraries are a useful tool in proteomic analyses. This study evaluated an antibody recombinant library for identification of sex-specific proteins on the sperm cell surface. The Griffin.1 library was used to produce phage antibodies capable of recognizing membrane proteins from Nelore sperm cells. After producing soluble monoclonal scFv, clones were screened on Simental sperm cells by flow cytometry and those that bound to 40–60% of cells were selected. These clones were re-analyzed using Nelore sperm cells and all clones bound to 40–60% of cells. Positive clones were submitted to a binding assay against male and female bovine leukocytes by flow cytometry and one clone preferentially bound to male cells. The results indicate that phage display antibodies are an alternative method for identification of molecules markers on sperm cells.

In vitro dose-response of carvacrol, thymol, eugenol and trans-cinnamaldehyde and interaction of combinations for the antimicrobial activity against the pig gut flora

May 2007

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601 Reads

In vitro simulations of the gastric and small intestinal fermentation with varying doses of carvacrol, thymol, eugenol and trans-cinnamaldehyde and binary combinations thereof were carried out to calculate dose–response equations for the antimicrobial effect against the main pig gut flora components. Interaction effects were evaluated following the isobole method. In gastric simulations eugenol and trans-cinnamaldehyde showed clearly less inhibitory activity towards lactobacilli than carvacrol and thymol, which could also be observed in the small intestinal simulations. The minimum concentration for carvacrol, thymol, eugenol and trans-cinnamaldehyde in small intestinal simulations to reduce the number of total anaerobic bacteria compared to control with a probability of 99.7% was 255, 258, 223 and 56 mg/l respectively. This strong activity of trans-cinnamaldehyde was due to its effect against coliform bacteria; a dose of 104 mg/l gave a reduction of 1 log CFU/ml vs. 371, 400 and 565 mg/l for carvacrol, thymol and eugenol respectively. Few combinations demonstrated synergism; most mixtures showed zero interaction or antagonism. Only carvacrol + thymol was slightly synergistic.

Days to calving in artificially inseminated beef cows: Comparison of potential traits

June 2007

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43 Reads

Four fertility traits were compared for artificially inseminated (AI) beef cows: A) for cows that calved to the AI sire (from either the initial or follow-up inseminations that season), the number days from initial AI to calving; B) for cows calving either by AI or to a backup bull, the number days from initial AI to calving; C) As trait B for cows that calved, otherwise the maximum of trait B for the contemporary group plus a penalty of 21 days; D) Define the ‘start date’ for a contemporary group as the date the first cow in the group was AI'd. For cows that calved, trait D was the number of days from the ‘start date’ to calving, otherwise the maximum of trait D for cows in the group that calved plus a penalty of 21 days.The vast majority of cows received only one insemination in a season, so trait A resembled gestation length and had estimated heritability of 12%. Traits B, C and D had estimated heritabilities of 3.2%, 3.5% and 5.2% respectively; estimated genetic correlations of traits A–D with naturally mated days to calving were 0.48, 0.60, 0.80 and 0.74 respectively. Trait D is therefore the recommended female fertility trait for AI cows. It has a similar frequency distribution to days to calving from natural mating and should be included in a joint analysis with days to calving of naturally mated cows.

Variation of gene frequencies in ASIP, MC1R and GREY loci in Thoroughbred horses

February 2008

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66 Reads

The objective of the study has been to verify the hypothesis that the coat colour is regarded in the selection of Polish Thoroughbred horse population. Formally, the colour is not a selection criterion in this breed selected mainly for speed. The material consisted of twelve groups of foals registered in successive volumes of the Stud Book (11,688 foals, in total) and their parents selected to the breeding stud. The frequency of alleles in ASIP, MC1R and GREY loci controlling the coat colours was estimated from the recessive phenotype frequency square in the groups of foals. The inflow of foreign genes was limited and the population great, hence the migration effect was very low. The drift and Wahlund effect hardly influenced the genetic structure in the groups which enabled to analyze the population not divided. The total offspring frequency of recessive a, e and g alleles amounted to 0.1552, 0.4877 and 0.9773, respectively. Accuracy of the assessment of the a and e frequency was confirmed on the basis of test matings. The a, e and g alleles were more frequent in dams than in sires and the a alleles occurred more often in fillies than in colts. The frequency of a and e alleles was higher in the offspring than in the parents. The genotype distribution in the offspring differed from the expected one, assessed from the gamete frequency in sires and in dams. Fewer bay foals were born than anticipated. All the results show that the coat colour is not entirely disregarded in the breeding of Thoroughbred horses. The dominant A and E alleles producing the colour are preferred in the selection, particularly in the sires. This leads to some alterations in the phenotypic structure of the population. On the other hand, the horses are mated randomly, irrespective of the coat colour.

Effects of supplemental magnesium aspartate and short-duration transportation on postmortem meat quality and gene expression of µ-calpain and calpastatin of finishing pigs

March 2009

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84 Reads

Twenty-four crossbred (Duroc × Large White × Yorkshire) finishing pigs (halothane-negative, mean live weight of 90 kg) were used to determine the effects of supplementing swine finishing diets with magnesium aspartate (MgAsp) and short-duration transportation stress on blood parameters, pork quality and μ-calpain and calpastatin mRNA levels in muscle of pigs. Transportation increased serum concentrations of calcium (Ca) (P < 0.05), phosphorus (P) (P < 0.01), glucose (P < 0.01) and cortisol (P < 0.01). Supplementation of MgAsp increased concentration of serum Mg (P = 0.057). Transportation decreased L⁎ value (P < 0.05) of biceps femoris (BF) at 45 min and 24 h, and b⁎ value of longissimus thoracis (LT) at 45 min (P = 0.073) after slaughter, and increased pH value of BF at 45 min (P < 0.05) and LT at 45 min (P = 0.098) after slaughter. However, transportation increased Warner–Bratzler shear force (WBSF) value of BF (P < 0.05) at aging 72 h and LT (P < 0.01) at aging 24 h and 72 h. Supplementation of MgAsp reduced L⁎ value (P < 0.05) of LT at 45 min, and BF at 45 min and at 24 h after slaughter, increased a⁎ value (P < 0.05) of BF at 45 min and had a trend to decline WBSF values of BF and LT at aging 24 h compared with the treatments fed the control diet. Transportation improved mRNA level of calpastatin of muscle (P < 0.05). Meanwhile, supplementation of MgAsp increased mRNA level of μ-calpain of muscle (P = 0.079). These results suggested that transportation stress increased postmortem color and pH value of pork and decreased tenderness of pork, and supplemental MgAsp improved color of pork and had a trend to decline WBSF, but did not influence drip loss and pH value of pork.

Assessment of early sexual maturity in nondescript local pigs of northeast India: Testicular development, spermiogram and in vivo pregnancy

July 2008

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162 Reads

The tribal population of North Eastern India follow a unique practice of mating the sow with a male pig from its own litter to avoid maintenance of boar for breeding. In this system, it is claimed that the nondescript local male pigs, at very young age (around 3 months), impregnate the sow. There is no documented report available on this practice. The present study, therefore, was carried out to study the testicular development and early sexual maturity in nondescript local pigs and to compare with Hampshire and Large White Yorkshire (LWY) pigs. The weight and circumference of the testes were significantly (p < 0.05) higher in nondescript local pigs compared to Hampshire and LWY pigs, but the testicular length did not differ significantly. The epididymis weight and length of different segments also did not differ significantly between Hampshire and LWY pigs. However, the nondescript local pigs had significantly heavier (p < 0.05) epididymal weights at four and six months of age relative to the other two breeds. The testicular tissue per kg body weight was significantly higher (p < 0.05) in nondescript local pigs than the Hampshire and LWY pigs. The progressive motility of cauda epididymal sperm was 30.5 ± 5.6 and 70.5 ± 4.8% at two and three months of age, respectively while the corresponding live percent were 57.9 ± 7.2 and 82.6 ± 6.4 in nondescript local pigs. The nondescript local male pigs could mate and impregnate the females as early as 108.8 ± 8.0 days of age. It was inferred that the testicular growth was faster in nondescript local pigs compared to Hampshire and LWY pigs and the nondescript local male pigs have the capacity to mate and impregnate sows at 3–4 months of age.

Association of bovine chromosome 5 markers with birth and weaning weight in Hereford cattle raised under extensive conditions

March 2011

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63 Reads

Genetic markers have been used to assess the association of economically important traits with cattle under intensive feeding conditions; however, there is still the need to ascertain the usefulness of these markers under extensive production systems. Bovine chromosome 5 has been widely studied because several QTLs have been detected. Microsatellite BP1 neighboring the Myogenic factor 5 gene (Myf5), and microsatellites ETH10, IGF1 and RM029 near Insulin-like Growth Factor 1 gene (IGF1), were selected to establish their association with BLUPs (Best Linear Unbiased Predictor) for direct Birth Weight (dBW), direct Weaning Weight (dWW) and maternal Weaning Weight (mWW). Two herds were used for this objective, one commercial and the other experimental. Associations (P ≤ 0.05) between dWW and all BTA5 loci (BP1, ETH10, IGF1, and RM029) were detected. Additional associations were observed between mWW and BP1. dBW was significantly associated (P ≤ 0.05) with ETH10 genotypes and with the interaction IGF1*Herd. In particular region near BP1 could be contributing to the rare positive correlation between dWW and mWW previously found in the INTA Balcarce Station experimental herd. We confirmed marker associations with growth traits in two BTA5 regions close to previously reported QTL obtained in intensive feeding conditions; these regions affect dBW, dWW and mWW in a pasture-based system.

An age-dependent association between a leptin C3469T single nucleotide polymorphism and intramuscular fat content in pigs

April 2009

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38 Reads

The objective of this work was to investigate whether the C3469T mutation at exon 3 of the pig leptin (Lep) gene is associated with fatness and if the magnitude and direction of these associations is consistent within age. Repeated measurements on body weight (BW), ultrasonic subcutaneous backfat (SB) and loin-muscle (LT) thickness, and intramuscular fat (IMF) content and composition were taken at 160, 180, 215 and 225 days of age on 162 Duroc barrows previously genotyped for the C3469T mutation. Plasma leptin concentration was determined at 180 days. A total of 505 records of IMF content and composition, which were determined both in live samples of longisimus dorsi muscle (LM) and in carcass samples of LM and gluteus medius muscle, were used in the analyses. The genotypic frequencies associated with the C3469T Lep mutation were 0.76, 0.23, and 0.01 for TT, TC, and CC genotypes, respectively. The effect of the Lep genotypes was assessed using a Bayesian approach based on a polynomial mixed model on age. No evidence was found for an association of the Lep genotypes neither with BW, SB thickness nor with plasma leptin concentration. The posterior mean of the difference TT–TC ranged, for LT, from 0.82 (160 days, posterior probability density (PP)> 0 of 87%) to 1.98 mm (220 days, PP > 0 of 96%) and, for IMF, from 0.96 (160 days, PP > 0 of 84%) to − 1.64 mg/g DM (220 days, PP > 0 of 2%). The results suggest an age-dependent association of the C3469T Lep polymorphism with LT and IMF, which may be useful to explain some controversial results in the literature concerning the association of this polymorphism with IMF content.

Patterns of work organisation in livestock farms: The ATELAGE approach

March 2009

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68 Reads

Expectations in terms of liveability are increasingly expressed by farmers within a context of society and market pressures on production processes and deep changes in farming itself (size of farms, workforce, off-farm activities, etc.), meaning that working conditions and the effectiveness of work organisation are critical issues today. In farming system modelling, farmers are portrayed as managers but not as work organisers or workers. Very few disciplinary conceptual frameworks or methodologies contribute to producing knowledge on work organisation in livestock farms, taking production processes into account. In this document, we present an approach at farm scale called ATELAGE, which represents and assesses work organisation in livestock farms, and the use of this approach combined with a hierarchical clustering to identify different patterns of work organisation that take account of farm diversity in a farm group. ATELAGE is based on livestock farming systems and ergonomic concepts and approaches. Work organisation is described at the scales of both time periods within the year and the whole agricultural year by forms of daily organisation. Criteria are proposed to assess variations in work organisation, and labour division in particular, that take account of the solutions adopted by livestock farmers to manage livestock production processes, workforce and non-agricultural activities including breaks and holidays, throughout a yearly production cycle. Three patterns of organisation emerged from ten studied livestock farms. This approach allows us to better understand organisational patterns, the farmers' situations and their practices. And thus it contributes to the debate on assessments of the way a system operates and to the design of new systems that incorporate work organisation as a dimension.

Genetic parameters for lean meat yield, meat quality, reproduction and feed efficiency traits for Australian pigs

August 2000

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122 Reads

Data from 1799 Large White and 1522 Landrace boars were used to obtain genetic correlations between production, carcase and meat quality traits. Variance components were obtained by REML procedures applying an average information algorithm. Traits analysed included average daily gain from 3 to 18 weeks of age (ADG1) and average daily gain, feed intake and feed conversion ratio from 18 to 22 weeks of age (ADG2, FDINT, FCR). Carcase traits included two backfat measurements and one muscle depth measurement taken on the live animal using realtime ultrasound and on the carcase using Hennesy Chong equipment. Further carcase traits included weight of the whole back leg (BLW) and weight of the ham (LMW). Meat quality traits included pH recorded 45 min (pH45) and 24 h after slaughter (pH24), colour of the m. longissimus dorsi (CLD) and m. multifidus dorsi (CMD), drip loss percentage (DLP) and intramuscular fat content (IMF). ADG1 was genetically a different trait than ADG2 (genetic correlation (rg): 0.32±0.23). Genetic correlations between these two traits and backfat measurements were favourable for ADG1 (rg: −0.35 to −0.21, ±0.13 to 0.22) and unfavourable for ADG2 (rg: 0.29 to 0.48, ±0.18 to 0.22). A lighter CLD was genetically related to a higher DLP and a lower pH. Estimates were higher between pH24, CLD and DLP (absolute rg: 0.71 to 0.83, ±0.11 to 0.14) than between pH45 and further meat quality traits (absolute rg: 0.12 to 0.44, ±0.23 to 0.24). Increasing IMF will improve other meat quality traits (rg: 0.06 to 0.48, ±0.19 to 0.24). Growth rate was genetically independent from meat quality traits (rg range: −0.31 to 0.35, ±0.18 to 0.31) while selection for improved feed efficiency and increased leanness will increase the incidence of PSE meat (absolute rg range: 0.00 to 0.66, ±0.14 to 0.31) and reduce IMF (rg: 0.16 to 0.34, ±0.15 to 0.27). Meat quality traits should therefore be included in selection indices in order to avoid further deterioration as a result of selection for higher leanness and feed efficiency.

Genetic characterization of the autochthonous sheep populations from Chiapas, Mexico

July 2008

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82 Reads

The Tzotziles, a Mayan native group located in Chiapas, Southern Mexico, have sheep breeding as one of their principal means of subsistence. Sheep were introduced in the Americas by the Spaniards in the first half of the XVI Century. Three populations of sheep from Chiapas—Café, Chamula and Chiapas—were typed with 27 microsatellites. Genetic distances were calculated for three Iberian breeds, Spanish Merino, Churra, two Canary Islands breeds, Canaria and Palmera, and the French Mutton Merino (Precoce). In the case of Chiapas sheep most of the markers showed Hardy–Weinberg equilibrium and the fixation index of Fst (0.095) showed a moderate level of genetic differentiation. The three distinct sheep subpopulations (Café, Chamula and Chiapas) are genetically differentiated inside the Chiapas sheep population. These breeds could be historically related to Spanish sheep populations, but have diverged significantly as a result of genetic drift and selection.


Voluntary intake and diet selection by dairy heifers fed ensiled whole-crop barley and oats harvested at different stages of maturity

May 2009

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73 Reads

This study evaluated feed intake and diet selection of dairy heifers fed whole-crop cereal silage made from oats and six-rowed barley harvested at the heading, early milk and early dough stages, and two-rowed barley harvested at the early milk and early dough stages of maturity. The silages were fed ad libitum to 32 Swedish Red dairy heifers, during three 17-day periods. The oat silage harvested at the early dough stage resulted in a higher dry-matter intake (DMI; 1.92 kg/100 kg live weight (LW)) and a higher organic matter intake (OMI; 1.73 kg/100 kg LW) than the oat silage harvested at the heading stage (DMI = 1.57 kg/100 kg LW; OMI = 1.37 kg/100 kg LW). The DMI, OMI and NDFI of six-rowed barley silage were higher when harvested at the heading stage (2.08, 1.80 and 1.06 kg/100 kg LW) than when harvested at the early milk (1.74, 1.48 and 0.76 kg/100 kg LW) and early dough stages (1.62, 1.46 and 0.70 kg/100 kg LW). The DMI, OMI and NDFI were higher for six-rowed barley than for oat silage harvested at heading, whereas feeding oat silage resulted in a higher NDFI than six-rowed barley silage when harvested at the early dough stage. Reduced intake of barley silage harvested at the early dough stage probably was due to the presence of barbed awns, whilst reduced intake of the early harvested oat silage was most likely due to a low DM content and a high content of fermentation products. When fed oat or two-rowed barley silage harvested at the early dough stage, the heifers selected fractions low in NDF. This indicates that heifers are likely to feed selectively when fed whole-crop cereal silages prepared from crops harvested at the early dough stage.

The effects of plastic slatted floor or straw bedding on performance, liver weight and liver copper concentrations in intensively reared lambs

April 2006

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128 Reads

One hundred and eight Texel sired lambs were weaned at 37 days old and allocated three days later to one of two treatments, using two pens per treatment, in order to evaluate lamb hepatic copper (Cu) values. In Treatment 1 (T1) the lambs were confined to pens having recycled plastic slatted flooring, while in Treatment 2 (T2) the lambs were confined to pens having straw bedded floors, with fresh straw added on alternate days. The lambs had ad libitum access to a coarse lamb concentrate. The crude protein (g/kg DM), crude fibre (g/kg DM), total zinc (mg/kg) and background levels of copper (Cu) (mg/kg) and molybdenum (Mo) (mg/kg) of the diet were 17.2, 10.9, 152, 9.7 and 0.92, respectively. The lambs were slaughtered when they reached about 39 kg live weight. Following slaughter, the liver was removed and weighed and the caudal lobe frozen for subsequent Cu analysis. The livers of lambs on the plastic floor treatment had higher liver weights (843 vs. 804 g, S.E.M. 11.0; P < 0.05) and higher hepatic copper (396 vs. 315 mg/kg DM, S.E.M. 18.2; P < 0.05) than those from lambs that were bedded with straw. The Cu accumulation per kg of liver DM per week was estimated to be 8.4 and 13.7 mg for lambs on the straw bedding and plastic slated treatments, respectively. It is concluded that when lambs are housed on plastic slatted flooring, relative to straw bedding, there is a higher accumulation of hepatic copper levels likely to result in a greater risk of Cu toxicity when lambs are reared on all concentrate diets.

Fig. 1. Average daily ambient temperature (T a ) and minimum wind chill index (WCI) during the experiment. 
Fig. 2. Core body temperature response of untreated (CON) or propylthiouracil-treated (PTU) goats exposed to chronic cold stress. 
Fig. 6. Subcutaneous temperature (T sq ) circadian biorhythm of untreated (CON) or propylthiouracil-treated (PTU) goats experiencing chronic cold stress. 
Responses of simultaneously recorded intraperitoneal and subcutaneous temperatures of Black Bedouin goats to transient thyrosuppression during cold stress

February 2007

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58 Reads

Unlike poikilotherms, homeotherms resist wide amplitudes of core body temperature (Tcore) fluctuation when exposed to reasonably variant ambient temperature (Ta) extremes. The degree of cold/heat thermotolerance varies tremendously amongst mammalian species. Thermotolerance can be partially inferred by the extent of resistance in body temperature displacement from normothermia when subjected to thermal stress. Regulation of thyroid calorigenic hormones is primarily contingent upon thermal homeostasis. Thyrosuppression generally exacerbates cold stress and hence may be a useful tool to examine the extent of cold-tolerance. An experiment was conducted to examine the extent of cold-tolerance on artificially goitrous Black Bedouin goats. Ten goat kids (initial Avg. BW = 30.6 ± 0.4 kg) were fitted with two miniature temperature data loggers, intraperitoneally and subcutaneously to identify core (Tcore) and subcutaneous (Tsq) temperature responses, respectively, to chronically (47 days) cold (< 10 °C) environment along with or without oral administration of the thyreostat propylthiouracil (PTU 20 mg/kg BW/day). Five animals served as controls (CON) whereas the remaining five were treated with PTU for 31 out of the overall 47-day observation period. Despite its 74.5%-evoked transient depression of circulating free thyroxine (FT4), PTU-treatment failed (P > 0.10) to cause significant displacements in Tcore or Tsq as compared to CON values throughout the 52-day trial period. As a function of Ta, Tcore − Tsq thermal gradient revealed a significantly (P < 0.01) linear regression (r2 = 0.41), to indirectly infer a graded blood redistribution from peripheral to splanchnic vascular beds with the fall in Ta. In the light of the current findings, it can be deduced that– in addition to the fact that it is superior in terms of heat-tolerance– the Black Bedouin goat is also profoundly cold-tolerant. Furthermore, our recently developed technique in concurrently recording Tcore and Tsq proves efficient and feasible to simultaneously record temperatures of different body sites in free-roaming animals, thereby overcoming potentially erroneous artifacts caused by frequent experimenter intrusion.

Genetic analyses for growth traits of two indigenous beef cattle breeds in Botswana

April 2010

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74 Reads

Genetic parameters for birth weight (BW), weaning weight (WW), pre-weaning average daily gain (ADG1), 18-months weight (18 MW) and post-weaning average daily gain (ADG2) were estimated using single-trait and multi-trait analyses. Data consisted of 2257 records for the Botswana Composite and 5923 records for the Tswana collected between the period of 1988 and 2006. The individual animal model (AM) and animal maternal model (AMM) were fitted in both analyses. Direct heritabilities for BW, WW, ADG1, 18 MW and ADG2 in the Tswana were respectively 0.45, 0.36, 0.37, 0.31 and 0.31, when the AM was fitted in single-trait analyses. Fitting the AMM gave direct and (maternal) heritabilities of respectively 0.31(0.11), 0.20(0.15) and 0.16(0.21) for BW, WW and ADG1 in the Tswana breed. Direct heritabilities for BW, WW and ADG1 in the Composite when the AM was fitted in single-trait analyses were respectively 0.58, 0.32 and 0.30. Direct and (maternal) heritabilities when the AMM was fitted for single-trait analyses in the Composite were 0.55(0.09), 0.17(0.15) and 0.14(0.15), respectively. When using multi-trait analyses and fitting the AM, the direct heritabilities for the Tswana were respectively 0.45, 0.37, 0.34, 0.39 and 0.31 for BW, WW, ADG1, 18 MW and ADG2. Genetic correlations among the live weight and growth traits ranged from 0.16 to 0.97. Direct and (maternal) heritabilities for BW, WW and ADG1 were respectively 0.31(0.11), 0.19(0.15) and 0.14(0.17) in the Tswana using the multi-trait analysis. Correlations between direct heritabilities for BW, WW and ADG1 ranged from 0.45 to 0.95 while maternal correlations ranged from 0.12 to 0.99. The magnitude of the heritabilities indicates an opportunity to make genetic progress through selection.

Breeding objectives for beef cattle used in different production systems: 2. Model application to production systems with the Charolais breed

August 2005

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986 Reads

A general bio-economic model for beef cattle production was used to define breeding objectives for Charolais cattle to be utilized in a variety of linked production systems. Economic weights were calculated for 16 traits (some with both direct and maternal components) in three production systems (pure-breeding and terminal crossing with beef or dairy cows) and two marketing strategies (sale or fattening of weaned surplus calves). Economic weights for the total breeding objective were calculated as weighted averages, where weights were numbers of cows expected to be mated with Charolais bulls in each production system and marketing strategy. Results suggest that the direct component of calving performance and cow longevity were of primary economic importance in all systems. Conception rate of cows and weaning weight reached about 50% of the standardized economic weight of calving performance in purebred systems with sale of weaned calves, whereas in purebred systems with fattening the economic importance of the direct component of cow conception rate, losses at calving, mature weight of cows, weaning weight, and fattening traits were of equal importance (each approximately about 20% that of calving performance). In terminal crossing systems, weaning weight was important when calves were sold at weaning, and fattening traits were important for systems selling fattened animals. The bio-economic model performed well under the conditions of this demonstration and could easily be customized for other applications.

Grazing behaviour, intake, rumen function and milk production of dairy cows offered Lolium perenne containing different levels of water-soluble carbohydrates

June 2006

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106 Reads

The aim of this study was to assess grazing behaviour, intake, rumen function, milk production and composition of dairy cows grazing perennial ryegrass varieties that were morphologically and chemically similar, but differed in their water-soluble carbohydrate (WSC) concentration. Eight multiparous rumen cannulated dairy cows were offered four varieties of perennial ryegrass under a 1-day strip-grazing system using a 4 × 4 Latin square design in two consecutive years. Two of the varieties were characterised by a high WSC content (HSV) and the other two varieties had a lower concentration of WSC (LSV). Grazing behaviour was recorded using a solid-state behaviour recorder. Daily intake was estimated using the n-alkane technique. Rumen function was measured using rumen evacuation. As expected the HSV had a higher WSC content (P < 0.05) than the LSV with an average difference of approximately 32 g/kg dry matter. The other chemical constituents did not differ significantly between HSV and LSV. The sward surface height, herbage allowance and tensile strength were not significantly different between HSV and LSV. None of the grazing behaviour parameters (eating time, rumination time, bite rate, chewing rate and bite mass) were significantly different between HSV and LSV. Daily dry matter intake (DMI), fibre clearance rate, milk production and milk composition (fat, protein and lactose) were not different between cows grazing the HSV and LSV. At the level of difference in WSC content between the grass varieties reported in this study (32 g/kg), offering dairy cows a high sugar pasture did not influence grazing behaviour and rumen function and was not beneficial in improving DMI, milk yield or in altering the composition of milk.

Table 7 Effect of milking frequency (once or twice) on locomotion scores (lsmean) of cows at four sampling dates
Table 9 Effect of milking frequency (once or twice) on differential counts (least-square means) of neutrophils and lymphocytes at five sampling dates
of milking frequency (once or twice) on the corre- lation between daily milking time and teat hyperkeratosis (HK) score in each month of lactation
Effect of milking frequency and nutritional level on hoof health, locomotion score and lying behaviour of dairy cows

February 2010

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151 Reads

This study evaluated the effect of milking frequency (MF; once a day (OAD) versus twice a day (TAD)) at two nutritional levels (NL) on hoof health, locomotion and lying behaviour of dairy cows. Cows (n = 72) were randomly assigned to one of four treatments from calving in a 2 × 2 factorial design for an entire lactation: OAD or TAD milking at a high (30.9 kg DM/c/d) or low (18.8 kg DM/c/d) herbage allowance NL. Hoof health (sole lesions, heel erosion, digital dermatitis and white line disease) and locomotory ability (including overall locomotion, ab/adduction, tracking, speed, head carriage and spine curvature scores) were assessed on 6 occasions between calving in the spring and housing the following autumn. Udder firmness was recorded in the milking parlour prior to milking at approximately 57, 93 and 132 days in milk (DIM). Standing/lying behaviour was recorded using modified voltage dataloggers over 2 × 24 h periods at approximately 157 and 208 DIM. Cows milked OAD had lower sole lesion (P < 0.05) and white line disease (P < 0.01) scores, but higher heel erosion scores (P < 0.05) than cows milked TAD. There was an interaction between time of examination and MF (P < 0.05) for locomotion scores; although in early lactation cows milked OAD had higher overall locomotion scores than TAD cows, this was reversed later in lactation. OAD cows had higher ab/adduction scores in early lactation (P < 0.05). On the other hand, speed and head carriage scores were all higher for TAD compared to OAD cows. High NL cows had higher overall ab/adduction (P < 0.01) scores, and at 57 DIM had higher udder tension scores than low NL cows (P < 0.001). Neither MF nor NL had an effect on total lying times. However cows on the high NL and OAD treatments spent less time standing after morning milking (P < 0.05), and spent more time per hour lying between 0900 and 1200. Cows milked OAD also spent more time than TAD cows lying between 1530 and 1830. High abduction scores in the OAD cows in early lactation may be related to discomfort in the udder. In general however, OAD milking resulted in improvements to hoof health and locomotion ability. Moreover, cows milked OAD use the extra time at pasture in the afternoon to rest, an option that is not available to TAD milked cows. Fewer disruptions to the diurnal pattern of OAD cows are an indication of improved welfare.

Fig. 1. Geographic situation of the last Guabala and Guaymi creoles cattle populations in the Republic of Panama. 
Study of genetic diversity of the Guaymi and Guabala bovine populations by means of microsatellites

June 2010

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223 Reads

A total of 61 individuals belonging to the Guaymi (GY) and Guabala (GUA) populations were typed with 27 microsatellites. A mean of 5.61 (GUA) and 7.5 (GY) alleles per population was typed, and Fis values were 0.053 (GUA) and 0.033 (GY). The exclusive alleles of each population were 67 (GY) compared to the 16 observed in the GUA population, while 135 alleles are shared by both. The Ho and He were 0.628 (GUA) and 0.710 (GY) and 0.648 (GUA) and 0.724 (GY) respectively. The fixation index Fst was 0.068 demonstrating a moderate level of genetic differentiation. The effective number of migrants per generations was 3.40 between GY and GUA. A comparison with most popular breeds in Panama Bos indicus (GYR, BRH, SIN, GUZ and NEL) and Bos taurus (FRI, SPA and HER) was made because of possible crossbreeding. The AMOVA and a NeighborNet tree performed, provided a detailed interrelationship network, and show an important difference between Panama creoles cattle population and most popular breeds. Strategies for preserving the original Panama cattle creole population should be considered in order to prevent the breed from becoming extinct and to strengthen the breed's capability in future breeding programs.

Random regression models to estimate test-day milk yield genetic parameters Holstein cows in Southeastern Brazil

July 2009

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223 Reads

A total of 152,145 weekly test-day milk yield records from 7317 first lactations of Holstein cows distributed in 93 herds in southeastern Brazil were analyzed. Test-day milk yields were classified into 44 weekly classes of DIM. The contemporary groups were defined as herd-year-week of test-day. The model included direct additive genetic, permanent environmental and residual effects as random and fixed effects of contemporary group and age of cow at calving as covariable, linear and quadratic effects. Mean trends were modeled by a cubic regression on orthogonal polynomials of DIM. Additive genetic and permanent environmental random effects were estimated by random regression on orthogonal Legendre polynomials. Residual variances were modeled using third to seventh-order variance functions or a step function with 1, 6, 13, 17 and 44 variance classes. Results from Akaike's and Schwarz's Bayesian information criterion suggested that a model considering a 7th-order Legendre polynomial for additive effect, a 12th-order polynomial for permanent environment effect and a step function with 6 classes for residual variances, fitted best. However, a parsimonious model, with a 6th-order Legendre polynomial for additive effects and a 7th-order polynomial for permanent environmental effects, yielded very similar genetic parameter estimates.

Effect of horse breed and sex on growth rate and radiographic closure time of distal radial metaphyseal growth plate

November 2011

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592 Reads

The aim of this study was to estimate the effect of breed and sex on the growth rate and the radiographic closure time of distal radial metaphyseal growth plate of horses of different breeds. The study used 81 animals comprising Thoroughbred (10 colts and 9 fillies), Arabian (10 colts and 10 fillies), Anglo-Arabian (10 colts and 11 fillies) and Hucul (10 colts and 11 fillies) breeds. On the basis of biometrical data the growth rate was estimated from birth to 20 months of age for each animal. To determine the time to radiographic closure of the distal radial metaphyseal growth plate radiographs of the left carpus of each animal were performed at 20 months and thereafter once monthly until growth plate closure. Thoroughbred and Arabian breeds exhibited significantly greater growth rate between birth and 20 months of age in comparison to Anglo-Arabians and Huculs. The earliest time of metaphyseal growth plate closure was achieved by Arabian horses (mean 718.1 days) and was significantly earlier than Hucul (mean 794.1 days) and Anglo-Arabian (mean 810.1 days) breeds. Mean time of growth plate closure of Thoroughbred horses (mean 756.3 days) was significantly shorter than in Anglo-Arabians. Within each breed metaphyseal growth plate closed earlier in fillies than in colts but only in Thoroughbreds the statistical differences were significant.

Geographical isolation of native sheep breeds in the UK—Evidence of endemism as a risk factor to genetic resources

August 2009

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99 Reads

This study addresses the potential risk to the genetic resources of UK sheep breeds from endemism. Twelve native breeds are analysed that exist in significant numbers and continue to be commercially farmed livestock. The breeds were selected to represent regions of the British Isles: North of England hill breeds (Herdwick, Rough Fell, Lonk, Dalesbred), South of England breeds (Southdown, Romney, Devon Closewool, Exmoor Horn), Scottish breed (South Country Cheviot) and Welsh/Welsh border breeds (Welsh Hill Speckled Face, South Wales Mountain (Nelson), Clun Forest).For each breed, numerical data were collected in collaboration with breed society members and analysed in terms of population size and structure together with the extent of their geographical range. The number of flocks per breed proved to be highly variable, questioning the assumption that has been made that the number of breeding units can be disregarded in the calculations of endangerment. The data also indicated that an average flock size for a breed cannot be estimated to gain an insight of the population structure, since this parameter was found to vary considerably within and between breeds. The endemism was best illustrated in the breed maps which clearly highlighted the degree to which each breed was associated with a distinct geographical area. From the maps, ten of the twelve breeds analysed were concentrated, but the flocks of two breeds were visually more dispersed. In numerical terms, the ten breeds were found to have up to 95% of their breed numbers concentrated within a radius of 65 km from the mean centre of each breed.The study provides a valuable foundation for future research into genetic diversity within and between the sheep breeds analysed, a baseline of information to enable population trends to be examined and a robust evidence-base for policy decisions on Farm Animal Genetic Resources (FAnGR).


Farmers' opinions on welfare, health and production practices in extensive hill sheep flocks in Great Britain

November 2006

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199 Reads

Despite large numbers of hill sheep reared in the UK, little is known about how hill farmers react to health challenges in their flocks. This paper addresses this lack of knowledge of sheep health management practices and presents farmers' opinions and concerns, particularly regarding ectoparasite control. Focus groups and interviews with UK hill sheep farmers were carried out to collect information on management practices, health concerns, in addition to incidence and impacts of six major ectoparasites (ticks, lice, sheep scab mite, blowfly, keds and headfly), to determine how they viewed the effects of ectoparasites and their control on production practices.We conclude that despite variations between hill sheep farm conditions and levels of input, similar health concerns and ectoparasite issues were found across different hill sheep farming areas of the UK. Farm labour was also an important issue and most farmers would prefer more labour to be available to effectively manage ectoparasites in their flocks. Finally, there was variation in farmers' opinions of the impact of ectoparasite species on welfare and productivity. This variation in opinion can be related to a trend in their past experience of ectoparasites, but no relationships were found with the animal health treatments farmers use, the number of animals in their flock or variation in the type of grazing land available.

Use of competition data for genetic evaluations of eventing horses in Britain: Analysis of the dressage, showjumping and cross country phases of eventing competition

October 2008

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139 Reads

Competition data on UK eventing horses were used to estimate genetic and phenotypic parameters. Penalty points from each of the three phases – dressage, showjumping and cross country – and overall competition were converted to normal scores for analysis. Because horses compete at different levels each phase was separated into 4 different grades of competition — pre novice, novice, intermediate and advanced, where pre novice is the lowest grade and advanced the highest. Data were analysed with an antedependence model of order 1 using ASReml. Fixed effects were sex, age and competition and the random effects were sire, horse and rider. Results showed heritabilities significantly different from zero for dressage (0.09–0.11), showjumping (0.08–0.23), cross country (0.02–0.03) and overall competition (0.05). Correlations between the grades for each phase were high, suggesting that it should be possible to predict a horse's performance at advanced level by its performance at novice and pre novice level. Correlations between each phase were highest between the showjumping and cross country phases. For the first time, the proportions of variance attributed to the rider, permanent environmental effect and genetics of the horse were estimated separately. These estimates showed that for most grades and phases the most important component was the permanent environmental effect, with the rider and genetics becoming more important as the grades become more challenging. The rider effect was greatest for dressage and the genetic effect was greatest for showjumping.

Effect of crude protein and phosphorus level in a phytase supplemented grower finisher pig diet on phosphorus and calcium metabolism

September 2010

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15 Reads

The objective of this study was to investigate the effects of dietary crude protein level (CP) on mineral metabolism in a low and high phosphorus (P) diet supplemented with phytase. A 2 × 2 factorial experiment was conducted to investigate the effect of CP inclusion (130 versus 200 g/kg) and dietary P inclusion (4.0 versus 6.0 g/kg) on P and calcium (Ca) metabolism in pigs. The dietary treatments contained 500 FTU/kg of phytase. Sixteen entire male pigs (body weight 78 kg) were randomly allocated to the diets in a digestibility and mineral balance study. Pigs offered high P diets had higher faecal dry matter output (P < 0.05) than pigs offered low P diets. Pigs offered low P diets had a higher dry matter digestibility (P < 0.01) than those offered high P diets. Pigs offered high CP diets had a higher urine pH than those offered low CP diets (P < 0.001). Pigs offered low P diets had higher N digestibility than those offered high P diets (P < 0.05). Pigs offered low P diets had a higher P (P < 0.05) and Ca (P < 0.01) digestibility than those offered high P diets. In conclusion dietary CP level had little impact on Ca and P digestibility however offering grower finisher pigs a high P diet supplemented with phytase resulted in a decrease in N digestibility.


Estimates of genetic parameters for scrotal circumference using random regression models in Nelore cattle

May 2011

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30 Reads

A total of 15,901 scrotal circumference (SC) records from 5300 Nelore bulls, ranging from 229 to 560 days of age, were used with the objective of estimating (co)variance functions for SC, using random regression models. Models included the fixed effects of contemporary group and age of dam at calving as covariable (linear and quadratic effects). To model the population mean trend, a third order Legendre polynomial on animal age was utilized. The direct additive genetic and animal permanent environmental random effects were modeled by Legendre polynomials on animal age, with orders of fit ranging from 1 to 5. Residual variances were modeled considering 1 (homogeneity of variance) or 4 age classes. Results obtained with the random regression models were compared to multi-trait analysis. (Co)variance estimates using multi-trait and random regression models were similar. The model considering a third- and fifth-order Legendre polynomials for additive genetic and animal permanent environmental effects, respectively, was the most adequate to model changes in variance of SC with age. Heritability estimates for SC ranged from 0.24 (229 days of age) to 0.47 (300 days of age), remained almost constant until 500 days of age (0.52), decreasing thereafter (0.44). In general, the genetic correlations between measures of scrotal circumference obtained from 229 to 560 days of age decreased with increasing distance between ages. For genetic evaluation scrotal circumference could be measured between 400 and 500 days of age.

Prevalence of lameness and of associated claw disorders in Greek dairy cattle industry

June 2009

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24 Reads

The aim of this study was to assess the prevalence of lameness as well as the prevalence of claw–horn disruptions, abnormal claw shape and dermatitis in lame cows in Greek dairy farms and to evaluate their risk factors. Forty dairy farms were visited twice, during winter and during summer, and the lameness of milking cows was scored using a 5-point scale. In total 760 cows were lame (lameness score ≥ 3) and were further examined to identify macroscopically the claw disorders. The herd size, the trimming and footbathing frequency, the floor surface, the cleanness of the herd, the scraping frequency and the disinfectant used in the footbaths were recorded. The mean lameness prevalence was 18.7% and that of claw disorders observed in the lame cows was 75.4% for abnormal claw shape, 30.2% for dermatitis and 30.6% for claw–horn disruptions. Large herd size and the absence or only once per year trimming were associated with increased risk for the presence of lameness.

Voluntary intake of silages in dairy cows depending on chemical composition and in vitro gas production characteristics

January 2007

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38 Reads

A study was conducted to investigate the possibilities to develop models for predicting the relative silage dry matter intake (SDMI) in dairy cows utilising information on chemical composition and in vitro gas production (GP) kinetics of silages. In five experiments, each with an average of 38 lactating dairy cows, SDMI was recorded for 15 grass silages made from primary growth and regrowth swards of timothy (Phleum pratense L.). The silages were characterised by chemical analysis and by utilising an automated in vitro GP recording technique with end point measurements of substrate residues. The silage samples were analysed both as dried and wet samples to evaluate the effects of sample preparation techniques on GP kinetics and their relations to SDMI. Relationships between feed variables and SDMI were investigated utilising simple linear and multiple regression. The wet silage samples had higher cumulative GP and different GP curves compared to the dried samples. The linear relationships between, GP variables, harvest number (first or second cut) of the grass, chemical characteristics of the silages and the relative SDMI show that the GP technique is a powerful tool to detect silage quality. By using the parameters from the dried samples the multiple regression analysis resulted in a relationship, relative SDMI (kg per 100 kg live weight (LW)) per day = 0.071 + 0.0029 × NDFD − 0.266 × C (R2 = 0.82, S.D. = 0.06). NDFD is the degradability of the neutral detergent fibre (NDF) (g/kg NDF) and C is the variable that regulates the switching characteristics of the GP profiles. By using the wet silage samples the multiple relationship did not include any GP variable; relative SDMI (kg per 100 kg LW per day) = 1.86 − 0.008 × acetic acid (g/kg DM) + 0.024 × ethanol (g/kg DM) (R2 = 0.62, S.D. = 0.08). The results from the regression analysis and the experience of the laborious sample preparation technique for wet samples, give the conclusion that dried silage samples are recommended for determining feed characteristics using the GP technique in intake studies.

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