Our objective was to study the effect of duration of milk storage on milk fat globule (MFG) secre... more Our objective was to study the effect of duration of milk storage on milk fat globule (MFG) secretion to better understand relationships between milk yield, milk fat and MFG secretion. Four milking frequencies were studied in 6 dairy cows averaging 118 ± 22 dim: 2 milkings/d separated by 11- and 13-h intervals (2M11-13) or by 4- and 20-h (2M4-20) and 1 milking/d (1M24). The experimental trial was a double Latin square 3 × 3 with 2 wk periods. In post-experiment, milking frequency of 36-h (1M36) was repeated twice. Compared with 2M11-13, 1M24 reduced milk and milk fat yields and increased fat content, without any effect on the size of MFG which agrees with previous research. 2M4-20 had no significant effect on milk fat yield and content but tended to increase the size of the MFG. Lipolysis, measured on morning milk, was weaker with 1M24. Milk fatty acid composition was not modified by milking frequency. When data were analyzed according to kinetics of milk storage duration (from 4 to...
The aim of this experiment was to compare the effects of increasing amounts of extruded linseed i... more The aim of this experiment was to compare the effects of increasing amounts of extruded linseed in dairy cow diet on milk fat yield, milk fatty acid (FA) composition, milk fat globule size, and butter properties. Thirty-six Prim'Holstein cows at 104 d in milk were sorted into 3 groups by milk production and milk fat globule size. Three diets were assigned: a total mixed ration (control) consisting of corn silage (70%) and concentrate (30%), or a supplemented ration based on the control ration but where part of the concentrate energy was replaced on a dry matter basis by 2.1% (LIN1) or 4.3% (LIN2) extruded linseed. The increased amounts of extruded linseed linearly decreased milk fat content and milk fat globule size and linearly increased the percentage of milk unsaturated FA, specifically alpha-linolenic acid and trans FA. Extruded linseed had no significant effect on butter color or on the sensory properties of butters, with only butter texture in the mouth improved. The LIN2 ...
The objective of this study was to examine the synthesis and composition of milk produced by dair... more The objective of this study was to examine the synthesis and composition of milk produced by dairy cows that secrete either small milk fat globules (SMFG) or large milk fat globules (LMFG), and to study their response to diets known to alter milk composition. Four groups of 3 multiparous dairy cows were assigned to 2 isoenergetic feeding treatments: a corn silage treatment supplemented with soybean meal, and fresh pasture supplemented with cereal concentrate. The 4 groups comprised 2 groups of 3 dairy cows that produced SMFG (3.44 microm) and 2 groups of 3 dairy cows that produced LMFG (4.53 microm). The SMFG dairy cows produced higher yields of milk, protein, and calcium. Nevertheless, their milk had lower fat and protein contents. Both SMFG and LMFG cows secreted similar amounts of milk fat; therefore, higher globule membrane contents in milk fat were observed in SMFG cows. Higher calcium mineralization of the casein micelles in SMFG cows suggests that it may be possible to improv...
Fresh grass in the cow diet improves the rheological and nutritional properties of butter. Howeve... more Fresh grass in the cow diet improves the rheological and nutritional properties of butter. However, the relationship between the proportion of fresh grass in the diet and these properties is still unknown. The objective of the study was to determine the relationship between the proportion of fresh grass in the diet and the properties of milk and butter. Four groups of 2 cows were fed 4 isoenergetic diets characterized by increasing amounts of fresh grass (0, 30, 60, and 100% dry matter of forage) according to a Youden square design. Energy levels were similar among all diets. Thus, no effect of mobilization was observed and the results were only due to the proportion of fresh grass in the diet. Milk yield linearly increased with the proportion of fresh grass in the diet (+0.21 kg/d per 10% of grass). Fat yield remained unchanged. Thus, by effect of dilution, increasing the proportion of fresh grass in the diet induced a linear decrease in fat content. Milk fat globule size decreased...
We conducted two trials to study the effect of graded amounts of glucose infused into the duodenu... more We conducted two trials to study the effect of graded amounts of glucose infused into the duodenum on milk yield and composition as well as on plasma metabolites, using diets based on grass silage. In trial 1, four fistulated Holstein cows were arranged in a 4 x 4 Latin square design and received 0, 750, 1500, and 2250 g of glucose/d in the duodenum. In trial 2, five fistulated Holstein cows were arranged in a 5 x 5 Latin square design and received 0, 250, 500, 1000, and 2000 g/d of glucose. In both trials, cows were fed a basal diet of 38% grass silage, 10% dehydrated alfalfa, 49% energy concentrate, and 3% oil meal. The treatments (feed plus infusion) were isoenergetic and isonitrogenous. Increased amounts of glucose increased milk yield up to 2.4 and 1.6 kg/d in trials 1 and 2, respectively. Lactose content was not affected, while fat yield and content decreased linearly. The decrease in milk fat resulted from a reduced yield of C18, probably caused by a lower mobilization of fat...
Four fistulated Holstein cows were arranged in a 4 x 4 Latin square design to study the effects o... more Four fistulated Holstein cows were arranged in a 4 x 4 Latin square design to study the effects of graded amounts of glucose (0, 500, 750, and 1500 g/d) infused in the duodenum on milk yield and composition and plasma metabolites. Cows were fed a basal diet of 50% corn silage, 17% dehydrated alfalfa, and 33% concentrate. The treatments (feed plus infusions) were isoenergetic. Increased amounts of glucose did not affect milk yield or protein content. Fat yield and content decreased in a curvilinear manner; the lowest fat content was obtained with about 750 g of glucose. The decrease in milk fat resulted from a reduced yield of long-chain fatty acids (C16 and C18), probably caused by lower mobilization of fat. The glucose treatments significantly affected profiles of medium-chain fatty acids, which promoted the elongation process. The most important change in the plasma concentration of amino acids concerned decreased branched-chain amino acids. The lactose content was not greatly aff...
Four fistulated Holstein cows were arranged in a 4 x 4 Latin square design to study the effects o... more Four fistulated Holstein cows were arranged in a 4 x 4 Latin square design to study the effects of level and type of energy source on milk yield and composition. Treatments consisted of a basal diet fed alone (low energy treatment) or with 3.3 Mcal of net energy for lactation from extra nutrients perfused either into the rumen (either propionic acid or a mixture of volatile fatty acids) or into the duodenum (glucose). Increasing the energy input without changing the volatile fatty acid profile improved milk yield and slightly increased milk protein and fat yields. Compared with the isoenergetic mixture of volatile fatty acids, both propionic acid and glucose infusions significantly decreased fat content (-4.5 g/kg) and yields (respectively, -111 and -160 g/d), but affected fatty acid proportion and yield differently (more elongation process and less C18 with glucose infusion). Protein yield was slightly increased by propionic acid infusion but not by glucose because of the counterba...
Milk protein secretion is changed by increasing the proportion of energy, mainly as propionic aci... more Milk protein secretion is changed by increasing the proportion of energy, mainly as propionic acid, or the availability of AA. Whether associative effects exist between energy nature and protein amounts is unknown. Therefore, ruminal isoenergetic infusions of low or high propionate mixtures were combined factorially with duodenal infusion of sodium caseinate or control. Four ruminally and duodenally fistulated Holstein cows were used. The diet was limited and consisted of 70% forage and 30% concentrate. Caseinate infusion increased milk yield and protein and casein contents and decreased milk fat content; curd yields and coagulation properties of milk were improved. The infusion of propionic acid caused a large increase in rumen propionate. Milk yield tended to decrease, and milk fat decreased, but protein, casein, and curd yields were unchanged; milk-coagulating properties were improved. No interaction existed between energy and protein amounts. Alteration of VFA had little effect ...
The aim of this study was to validate the measurement of glucose appearance rate using [6,6-2H2]g... more The aim of this study was to validate the measurement of glucose appearance rate using [6,6-2H2]glucose i.v. infusion in lactating dairy cows. Sample enrichments were analysed by gas chromatography/mass spectrometry. Linearity (enriched solutions) and specificity (enriched plasma) were good: for enrichments ranging between 1.6 and 6.3 mol% excess, the slopes were about 1 and the ordinates at the origin were not different from zero. For a plasma enriched at 3.74 mol% excess, repeatability and long term intralaboratory reproducibility coefficients of variation were 1.31 and 1.90%, respectively. The appearance rates were calculated by two models. The values provided by the steady-state model were not different from those provided by the non-steady-state Steele model. Both models can be used because the treatment effects were similarly discriminated regardless of the model. In our experiments analysing the nutritional effects on Ra in mid-lactating cows, the precision of the method (1.9...
ABSTRACT La vocation des ontologies est de faciliter l'organisation et l'exploita... more ABSTRACT La vocation des ontologies est de faciliter l'organisation et l'exploitation des connaissances et des données produites en grande quantité notamment en biologie. L'ontologie ATOL (http://www.atol-ontology.com) pour "Animal Trait Ontology for Livestock" a été dédiée à la définition et l'organisation des caractères phénotypiques des animaux d'élevage (poisson, oiseaux, mammifères). Or, un phénotype résulte de l'action commune d'un génotype et de son environnement (plus des mécanismes épigénétiques). Sa définition nécessite donc aussi une description précise de l'environnement d'élevage. L'ontologie EOL pour "Environnement Ontology for Livestock" a été ainsi créée pour décrire, de manière générique, les systèmes et conditions d'élevage. La combinaison des concepts des caractères phénotypiques des animaux (ATOL) et de ceux des conditions d'élevage (EOL) permettra la standardisation et l'annotation très précise des bases de données phénotypiques. Elle facilitera les approches intégratives et systémiques grâce à la représentation univoque des concepts en un langage partagé, commun aux différents utilisateurs et à l'accès automatisé à ces concepts rendu possible par des logiciels. Ces deux ontologies constituent un outil prometteur pour des projets d'expérimentation en particulier ceux portant sur l'élevage de précision, et à un appui méthodologique aux programmes d'amélioration génétique prédictive. Elles devraient être aussi de puissants outils pour la recherche d'informations dans les documents scientifiques et techniques, par les logiciels de pointe d'ores et déjà disponibles mobilisant l'analyse sémantique. Dans cet article la structure des ontologies, leurs caractéristiques et leurs applications en productions animales sont présentées et illustrées dans le domaine de la production porcine.
Our objective was to study the effect of duration of milk storage on milk fat globule (MFG) secre... more Our objective was to study the effect of duration of milk storage on milk fat globule (MFG) secretion to better understand relationships between milk yield, milk fat and MFG secretion. Four milking frequencies were studied in 6 dairy cows averaging 118 ± 22 dim: 2 milkings/d separated by 11- and 13-h intervals (2M11-13) or by 4- and 20-h (2M4-20) and 1 milking/d (1M24). The experimental trial was a double Latin square 3 × 3 with 2 wk periods. In post-experiment, milking frequency of 36-h (1M36) was repeated twice. Compared with 2M11-13, 1M24 reduced milk and milk fat yields and increased fat content, without any effect on the size of MFG which agrees with previous research. 2M4-20 had no significant effect on milk fat yield and content but tended to increase the size of the MFG. Lipolysis, measured on morning milk, was weaker with 1M24. Milk fatty acid composition was not modified by milking frequency. When data were analyzed according to kinetics of milk storage duration (from 4 to...
The aim of this experiment was to compare the effects of increasing amounts of extruded linseed i... more The aim of this experiment was to compare the effects of increasing amounts of extruded linseed in dairy cow diet on milk fat yield, milk fatty acid (FA) composition, milk fat globule size, and butter properties. Thirty-six Prim'Holstein cows at 104 d in milk were sorted into 3 groups by milk production and milk fat globule size. Three diets were assigned: a total mixed ration (control) consisting of corn silage (70%) and concentrate (30%), or a supplemented ration based on the control ration but where part of the concentrate energy was replaced on a dry matter basis by 2.1% (LIN1) or 4.3% (LIN2) extruded linseed. The increased amounts of extruded linseed linearly decreased milk fat content and milk fat globule size and linearly increased the percentage of milk unsaturated FA, specifically alpha-linolenic acid and trans FA. Extruded linseed had no significant effect on butter color or on the sensory properties of butters, with only butter texture in the mouth improved. The LIN2 ...
The objective of this study was to examine the synthesis and composition of milk produced by dair... more The objective of this study was to examine the synthesis and composition of milk produced by dairy cows that secrete either small milk fat globules (SMFG) or large milk fat globules (LMFG), and to study their response to diets known to alter milk composition. Four groups of 3 multiparous dairy cows were assigned to 2 isoenergetic feeding treatments: a corn silage treatment supplemented with soybean meal, and fresh pasture supplemented with cereal concentrate. The 4 groups comprised 2 groups of 3 dairy cows that produced SMFG (3.44 microm) and 2 groups of 3 dairy cows that produced LMFG (4.53 microm). The SMFG dairy cows produced higher yields of milk, protein, and calcium. Nevertheless, their milk had lower fat and protein contents. Both SMFG and LMFG cows secreted similar amounts of milk fat; therefore, higher globule membrane contents in milk fat were observed in SMFG cows. Higher calcium mineralization of the casein micelles in SMFG cows suggests that it may be possible to improv...
Fresh grass in the cow diet improves the rheological and nutritional properties of butter. Howeve... more Fresh grass in the cow diet improves the rheological and nutritional properties of butter. However, the relationship between the proportion of fresh grass in the diet and these properties is still unknown. The objective of the study was to determine the relationship between the proportion of fresh grass in the diet and the properties of milk and butter. Four groups of 2 cows were fed 4 isoenergetic diets characterized by increasing amounts of fresh grass (0, 30, 60, and 100% dry matter of forage) according to a Youden square design. Energy levels were similar among all diets. Thus, no effect of mobilization was observed and the results were only due to the proportion of fresh grass in the diet. Milk yield linearly increased with the proportion of fresh grass in the diet (+0.21 kg/d per 10% of grass). Fat yield remained unchanged. Thus, by effect of dilution, increasing the proportion of fresh grass in the diet induced a linear decrease in fat content. Milk fat globule size decreased...
We conducted two trials to study the effect of graded amounts of glucose infused into the duodenu... more We conducted two trials to study the effect of graded amounts of glucose infused into the duodenum on milk yield and composition as well as on plasma metabolites, using diets based on grass silage. In trial 1, four fistulated Holstein cows were arranged in a 4 x 4 Latin square design and received 0, 750, 1500, and 2250 g of glucose/d in the duodenum. In trial 2, five fistulated Holstein cows were arranged in a 5 x 5 Latin square design and received 0, 250, 500, 1000, and 2000 g/d of glucose. In both trials, cows were fed a basal diet of 38% grass silage, 10% dehydrated alfalfa, 49% energy concentrate, and 3% oil meal. The treatments (feed plus infusion) were isoenergetic and isonitrogenous. Increased amounts of glucose increased milk yield up to 2.4 and 1.6 kg/d in trials 1 and 2, respectively. Lactose content was not affected, while fat yield and content decreased linearly. The decrease in milk fat resulted from a reduced yield of C18, probably caused by a lower mobilization of fat...
Four fistulated Holstein cows were arranged in a 4 x 4 Latin square design to study the effects o... more Four fistulated Holstein cows were arranged in a 4 x 4 Latin square design to study the effects of graded amounts of glucose (0, 500, 750, and 1500 g/d) infused in the duodenum on milk yield and composition and plasma metabolites. Cows were fed a basal diet of 50% corn silage, 17% dehydrated alfalfa, and 33% concentrate. The treatments (feed plus infusions) were isoenergetic. Increased amounts of glucose did not affect milk yield or protein content. Fat yield and content decreased in a curvilinear manner; the lowest fat content was obtained with about 750 g of glucose. The decrease in milk fat resulted from a reduced yield of long-chain fatty acids (C16 and C18), probably caused by lower mobilization of fat. The glucose treatments significantly affected profiles of medium-chain fatty acids, which promoted the elongation process. The most important change in the plasma concentration of amino acids concerned decreased branched-chain amino acids. The lactose content was not greatly aff...
Four fistulated Holstein cows were arranged in a 4 x 4 Latin square design to study the effects o... more Four fistulated Holstein cows were arranged in a 4 x 4 Latin square design to study the effects of level and type of energy source on milk yield and composition. Treatments consisted of a basal diet fed alone (low energy treatment) or with 3.3 Mcal of net energy for lactation from extra nutrients perfused either into the rumen (either propionic acid or a mixture of volatile fatty acids) or into the duodenum (glucose). Increasing the energy input without changing the volatile fatty acid profile improved milk yield and slightly increased milk protein and fat yields. Compared with the isoenergetic mixture of volatile fatty acids, both propionic acid and glucose infusions significantly decreased fat content (-4.5 g/kg) and yields (respectively, -111 and -160 g/d), but affected fatty acid proportion and yield differently (more elongation process and less C18 with glucose infusion). Protein yield was slightly increased by propionic acid infusion but not by glucose because of the counterba...
Milk protein secretion is changed by increasing the proportion of energy, mainly as propionic aci... more Milk protein secretion is changed by increasing the proportion of energy, mainly as propionic acid, or the availability of AA. Whether associative effects exist between energy nature and protein amounts is unknown. Therefore, ruminal isoenergetic infusions of low or high propionate mixtures were combined factorially with duodenal infusion of sodium caseinate or control. Four ruminally and duodenally fistulated Holstein cows were used. The diet was limited and consisted of 70% forage and 30% concentrate. Caseinate infusion increased milk yield and protein and casein contents and decreased milk fat content; curd yields and coagulation properties of milk were improved. The infusion of propionic acid caused a large increase in rumen propionate. Milk yield tended to decrease, and milk fat decreased, but protein, casein, and curd yields were unchanged; milk-coagulating properties were improved. No interaction existed between energy and protein amounts. Alteration of VFA had little effect ...
The aim of this study was to validate the measurement of glucose appearance rate using [6,6-2H2]g... more The aim of this study was to validate the measurement of glucose appearance rate using [6,6-2H2]glucose i.v. infusion in lactating dairy cows. Sample enrichments were analysed by gas chromatography/mass spectrometry. Linearity (enriched solutions) and specificity (enriched plasma) were good: for enrichments ranging between 1.6 and 6.3 mol% excess, the slopes were about 1 and the ordinates at the origin were not different from zero. For a plasma enriched at 3.74 mol% excess, repeatability and long term intralaboratory reproducibility coefficients of variation were 1.31 and 1.90%, respectively. The appearance rates were calculated by two models. The values provided by the steady-state model were not different from those provided by the non-steady-state Steele model. Both models can be used because the treatment effects were similarly discriminated regardless of the model. In our experiments analysing the nutritional effects on Ra in mid-lactating cows, the precision of the method (1.9...
ABSTRACT La vocation des ontologies est de faciliter l'organisation et l'exploita... more ABSTRACT La vocation des ontologies est de faciliter l'organisation et l'exploitation des connaissances et des données produites en grande quantité notamment en biologie. L'ontologie ATOL (http://www.atol-ontology.com) pour "Animal Trait Ontology for Livestock" a été dédiée à la définition et l'organisation des caractères phénotypiques des animaux d'élevage (poisson, oiseaux, mammifères). Or, un phénotype résulte de l'action commune d'un génotype et de son environnement (plus des mécanismes épigénétiques). Sa définition nécessite donc aussi une description précise de l'environnement d'élevage. L'ontologie EOL pour "Environnement Ontology for Livestock" a été ainsi créée pour décrire, de manière générique, les systèmes et conditions d'élevage. La combinaison des concepts des caractères phénotypiques des animaux (ATOL) et de ceux des conditions d'élevage (EOL) permettra la standardisation et l'annotation très précise des bases de données phénotypiques. Elle facilitera les approches intégratives et systémiques grâce à la représentation univoque des concepts en un langage partagé, commun aux différents utilisateurs et à l'accès automatisé à ces concepts rendu possible par des logiciels. Ces deux ontologies constituent un outil prometteur pour des projets d'expérimentation en particulier ceux portant sur l'élevage de précision, et à un appui méthodologique aux programmes d'amélioration génétique prédictive. Elles devraient être aussi de puissants outils pour la recherche d'informations dans les documents scientifiques et techniques, par les logiciels de pointe d'ores et déjà disponibles mobilisant l'analyse sémantique. Dans cet article la structure des ontologies, leurs caractéristiques et leurs applications en productions animales sont présentées et illustrées dans le domaine de la production porcine.
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