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Goat energy balance and milk long-chain fatty acids (FA) (from Chilliard, 1985, and Chilliard et al., 1987). Milk fat content and FA composition were studied in 108 milk samples from 19 Alpine goats, receiving alfalfa hay and concentrate, between wk 1 and 18 of lactation; = lactation after normal parturition (10 goats); ᭝ = lactation after abortion (4 goats); ᮀ = hormonally induced lactation in nonpregnant goats (5 goats). The following correlations were observed: milk C18:0 + C18:1 (%) versus energy balance, r = − 0.77; milk fat content versus energy balance, r = − 0.58; milk fat content versus plasma NEFA content, r = + 0.46; milk fat content versus milk C18:1 (%), r = + 0.47.
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Although the effect of lactation stage is similar, the responses of milk yield and composition (fat and protein contents) to different types of lipid supplements differ greatly between goats and cows. Milk fat content increases with almost all studied fat supplements in goats but not in cows. However, the response of milk fatty acid (FA) compositio...
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Context 1
... of this paper is to review the main effects of physiological and nutritional factors, and more par- ticularly recent studies on fat supplementation, on goat milk fat and protein contents, fatty acid composition, lipase activity and lipolysis. In comparison with cow milk, goat milk is higher in medium-chain FA (C8, caprylic acid and, more markedly, C10, capric acid). Conversely, cow milk is higher in butyric (C4) and, sometimes, palmitic (C16:0) acids (Glass et al., 1967). Thus, the regulation of mammary cells differs between caprine and bovine species, partic- ularly in the elongation process of FA, which are synthesized de novo by the “fatty acid synthase” complex. A detailed comparison of the mechanisms between these two species would contribute to a better knowledge of the regulation of milk fat synthesis in ruminants (Knudsen and Grunnet, 1982), which is less well known than in rodent species (Barber et al., 1997). Milk unsaturated FA may contain one or several trans double bonds. About 5 to 15% of total C18:1 are of trans configuration in goat (Bickerstaffe et al., 1972; Calderon et al., 1984; Alonso et al., 1999), cow (Storry and Rook, 1965; Selner and Schultz, 1980) and human species (Jensen, 1989; Guesnet et al., 1993). However, the proportion of different trans isomers varies between species: the main FA (35 to 40%) is trans -vaccenic acid (C18:1, n-7 or ∆ 11) in goat and cow milk (Bicherstaffe et al., 1972; Alonso et al., 1999; LeDoux et al., 2002; Figure 1A and B), whereas human milk fat trans C18:1 contains larger percentages of FA with the double bond located on carbons 6 to 14 (Figure 1C). The profile of human milk fat is probably related to the consumption of a mixture of ruminant milk fat and of margarines, the latter being richer in ∆ 6 to ∆ 14 - trans C18:1, especially ∆ 6 to ∆ 10 (Figure 1 D). Quantitatively, the trans C16:1 isomers represent less than 0.2% of total FA, or 5% of all trans C16:1 and C18:1 isomers in ruminant milk fat. The distribution patterns of cis and trans C16:1 isomers are very similar for goat, cow, and ewe cheese fat (Destaillats et al., 2000). The trans FA of margarines originate from industrial hydrogenation of polyunsaturated FA from vegetable oils, whereas ruminant trans FA originate from ruminal hydrogenation of polyunsaturated FA of forages and concentrates (Figure 2). Conjugated linoleic acid ( CLA ) is a precursor of trans -vaccenic acid in the rumen and a product of the delta-9 desaturation of this FA in the mammary gland (Figure 2). The major isomer (more than 90%) of bovine milk CLA ( cis -9, trans -11 C18:2, or rumenic acid, RA ) originates mainly from the latter pathway (Griinari and Bauman, 1999). It is interesting to emphasize that milk fat from monogastric farm animals such as mare or sow (that do not consume ruminant milk fat or margarines) is almost devoid of trans vaccenic acid and RA, whereas human milk fat is of an intermediate composition (Jahreis et al., 1999). In that study, the trans -vaccenic and RA contents of goat milk fat were lower than those of milk fat from cow or ewe receiving similar diets. However, the mean milk RA values from three other goat studies were in the range 0.4 to 0.9% of total FA (Alonso et al., 1999; Gulati et al., 2000; Chilliard et al., 2002), i.e., similar to observations in dairy cows receiving diets without added lipids (Griinari and Bauman, 1999; Chilliard et al., 2000). Milk fat content is high after parturition and then decreases during the major part of lactation in the goat (Chilliard et al., 1986; Sauvant et al., 1991) as in the cow (Jarrige et al., 1978). This is related to at least two phenomena: a dilution effect due to the increase in milk volume until the lactation peak, and a decrease in fat mobilization that decreases the availability of plasma NEFA, especially C18:0 and C18:1, for mammary lipid synthesis. Highly significant correlations were found between milk fat content and either energy balance, plasma NEFA content or milk fat C18:1 percentage, respectively (see Figure 3). The nutritional status of lactating animals can be estimated by their energy (or protein, mineral, etc.) balance, i.e., by the difference between ingested nutrients and requested nutrients for body maintenance and for milk secretion. This balance is highly variable, according to animal milk genetic potential and lactation stage, as well as to composition and nutrient density of the diet. When energy balance is negative, animals mobilize lipids stored in adipose tissues, mainly in the form of NEFA. As ruminant adipose tissues are very rich in palmitic, stearic, and oleic acids (see Bas et al., 1987, for goat tissues), this explains that 59% of the variability of milk C18:0 + C18:1 content (which represent from 15 to 45% of total milk FA) was linked to changes in energy balance, in goats with different milk yields, and receiving classic hay plus concentrate diets (without fat supplementation) during the first 4 mo of lactation (Figure 3). Correlations between the percentages of individual FA in these milks show three main families: C18-FA, C10 to C16-FA (negatively correlated to the C18-FA family), and C4 to C8-FA (not highly correlated to the two other families, with the exception of the negative correlation to C16:0) (Sauvant et al., 1973, and Figure 4). These correlations result mainly from the negative effect of long-chain (C18) FA that are mobilized from adipose tissue on de novo synthesis of medium-chain FA (C10 to C16; Barber et al., 1997), and from the fact that short-chain FA arise in part from metabolic pathways that do not involve malonyl-CoA and acetyl-CoA carboxylase activity (Bauman and Davis, 1974; Palmquist and Jenkins, 1980). Dietary factor (forage-to-concentrate ratio, type of forages, etc.) effects on goat milk composition have been reviewed by Morand-Fehr et al. (2000a). Dietary lipid supplementation is a means for increasing both energy intake and efficiency in early lactation-high yielding cows, thereby increasing milk yield, but it did not limit the mobilization of body lipids (Chilliard, 1993). Effects of lipid supplementation on goat milk secretion have been reviewed by Morand-Fehr et al. (1982) and Polidori et al. (1991). Feeding diets very low in lipids decreased goat milk yield and fat content, and this was reversed by lipid supplementation (Delage and Fehr, 1967; Morand-Fehr et al., 1984a, Table 1). In four early-lactation trials (Table 1), lipid supplementation tended to increase milk yield ( + 0.1 to + 0.4 kg/d or more when the control diet was very low in fat) and fat content ( + 2 to + 7 g/kg). Effects on protein content were highly variable. The calculated energy balance increased or decreased according to respective effects on intake of DM and energy, and milk fat secretion. In three other early-lactation trials, milk yield and protein content remained unchanged, and fat content increased, with either protected sunflower seeds (15% of concentrate; Morand-Fehr et al., 1984a), extruded soybeans (160 g/d; Morand-Fehr et al., 1984b) or calcium soaps of palm oil (100 g/d; Martin et al., 1999). There were no clear trends concerning effects of fat supplementation on goat BW changes or body fat mobilization during early lactation. Results from early-lactation experiments are limited by their lack of precision, linked to possible differences in milk potential of animals and limited use of covariates, when lipid supplementation begins before or immediately after parturition. Contrary to what was observed in dairy cows (Chilliard et al., 2001), feeding fat supplements to mid- or late-lactation goats did not increase milk yield, whereas milk fat content always increased sharply ( + 5.7 g/kg in 23 supplemented groups in Table 2). The ranges of observed responses were similar with different types of fat supplements: saturated free FA, calcium salts or triglycerides; animal fat; vegetable oils (C18:1-, C18:2-, or C18:3-rich oils; free oils, encapsulated oils); oilseed (whole, crushed, extruded, or formaldehyde-treated oil seeds) (Table 2, and Schmidely and Sauvant, 2001). Remarkably, goat milk fat content did not decrease even when vegetable oils (rich in polyunsaturated FA) were added to a low-forage diet (e.g., footnote 8 in Table 2), contrary to what was very clearly observed in dairy cows (Bauman and Griinari, 2001). As previously observed for early-lactation goats, response of milk protein content was highly variable in midlactation goats (Table 2). Body weight gain was either higher (Baldi et al., 1992), lower (Gelaye and Amoah, 1988), or unchanged (footnote 8 in Table 2) in fat supplemented vs. control goats. The response of dairy goats to fish oil supplements is not well known but differs from the responses to other fat supplements. Feeding unprotected fish oil to goats sharply decreased DMI and milk yield without changing milk fat content (Kitessa et al., 2001). This differs markedly from cow responses, where milk yield increased (despite a significant decrease in dry matter intake) and milk fat content decreased sharply (Chilliard and Doreau, 1997). Feeding partially protected fish oil (20 g/d of EPA + DHA) to goats did not change intake, milk yield, or milk fat content (Kitessa et al., 2001). This contradicts the results of L ́ger et al. (1994), showing that a duodenal infusion of EPA + DHA (4 g/d) decreased goat milk fat content, as observed in cows (Chilliard et al. 2000, 2001). The response of milk fat secretion to fat supplementation could be lower during midlactation than during early lactation (Figure 5). This could be related to the fact that goat adipose tissue anabolic enzymes involved in de novo lipogenesis, and lipoprotein lipase (the enzyme involved in the uptake of blood lipoproteins car- rying dietary FA absorbed from the intestine), are more active after the lactation peak than before it (Chilliard et al., 1977, 1979a), because they are positively related to energy balance ...
Context 2
... satisfaction of consumer demand. Dietary lipid supplementation may indeed change milk fat FA composition and result in positive or adverse changes in the physical characteristics and the nutritional or dietetic properties of goat dairy products, and/or modify the lipolytic system (Chilliard, 1982) and hence the flavor of these products. Furthermore, the expected positive effects of fat supplementation on goat milk fat content (Chilliard and Bocquier, 1993) could be useful in solving the technological problems of the goat cheese industry, which are linked to a low milk fat content, especially when fat content falls below protein content (the so-called “inversion of percentages syndrome”) (Morand-Fehr et al., 2000b). Although fat supplementation in dairy cows and ewes often decreases the milk protein content and the associated coagulation properties, this negative ef- fect could not exist in goats (Chilliard and Bocquier, 1993). The aim of this paper is to review the main effects of physiological and nutritional factors, and more par- ticularly recent studies on fat supplementation, on goat milk fat and protein contents, fatty acid composition, lipase activity and lipolysis. In comparison with cow milk, goat milk is higher in medium-chain FA (C8, caprylic acid and, more markedly, C10, capric acid). Conversely, cow milk is higher in butyric (C4) and, sometimes, palmitic (C16:0) acids (Glass et al., 1967). Thus, the regulation of mammary cells differs between caprine and bovine species, partic- ularly in the elongation process of FA, which are synthesized de novo by the “fatty acid synthase” complex. A detailed comparison of the mechanisms between these two species would contribute to a better knowledge of the regulation of milk fat synthesis in ruminants (Knudsen and Grunnet, 1982), which is less well known than in rodent species (Barber et al., 1997). Milk unsaturated FA may contain one or several trans double bonds. About 5 to 15% of total C18:1 are of trans configuration in goat (Bickerstaffe et al., 1972; Calderon et al., 1984; Alonso et al., 1999), cow (Storry and Rook, 1965; Selner and Schultz, 1980) and human species (Jensen, 1989; Guesnet et al., 1993). However, the proportion of different trans isomers varies between species: the main FA (35 to 40%) is trans -vaccenic acid (C18:1, n-7 or ∆ 11) in goat and cow milk (Bicherstaffe et al., 1972; Alonso et al., 1999; LeDoux et al., 2002; Figure 1A and B), whereas human milk fat trans C18:1 contains larger percentages of FA with the double bond located on carbons 6 to 14 (Figure 1C). The profile of human milk fat is probably related to the consumption of a mixture of ruminant milk fat and of margarines, the latter being richer in ∆ 6 to ∆ 14 - trans C18:1, especially ∆ 6 to ∆ 10 (Figure 1 D). Quantitatively, the trans C16:1 isomers represent less than 0.2% of total FA, or 5% of all trans C16:1 and C18:1 isomers in ruminant milk fat. The distribution patterns of cis and trans C16:1 isomers are very similar for goat, cow, and ewe cheese fat (Destaillats et al., 2000). The trans FA of margarines originate from industrial hydrogenation of polyunsaturated FA from vegetable oils, whereas ruminant trans FA originate from ruminal hydrogenation of polyunsaturated FA of forages and concentrates (Figure 2). Conjugated linoleic acid ( CLA ) is a precursor of trans -vaccenic acid in the rumen and a product of the delta-9 desaturation of this FA in the mammary gland (Figure 2). The major isomer (more than 90%) of bovine milk CLA ( cis -9, trans -11 C18:2, or rumenic acid, RA ) originates mainly from the latter pathway (Griinari and Bauman, 1999). It is interesting to emphasize that milk fat from monogastric farm animals such as mare or sow (that do not consume ruminant milk fat or margarines) is almost devoid of trans vaccenic acid and RA, whereas human milk fat is of an intermediate composition (Jahreis et al., 1999). In that study, the trans -vaccenic and RA contents of goat milk fat were lower than those of milk fat from cow or ewe receiving similar diets. However, the mean milk RA values from three other goat studies were in the range 0.4 to 0.9% of total FA (Alonso et al., 1999; Gulati et al., 2000; Chilliard et al., 2002), i.e., similar to observations in dairy cows receiving diets without added lipids (Griinari and Bauman, 1999; Chilliard et al., 2000). Milk fat content is high after parturition and then decreases during the major part of lactation in the goat (Chilliard et al., 1986; Sauvant et al., 1991) as in the cow (Jarrige et al., 1978). This is related to at least two phenomena: a dilution effect due to the increase in milk volume until the lactation peak, and a decrease in fat mobilization that decreases the availability of plasma NEFA, especially C18:0 and C18:1, for mammary lipid synthesis. Highly significant correlations were found between milk fat content and either energy balance, plasma NEFA content or milk fat C18:1 percentage, respectively (see Figure 3). The nutritional status of lactating animals can be estimated by their energy (or protein, mineral, etc.) balance, i.e., by the difference between ingested nutrients and requested nutrients for body maintenance and for milk secretion. This balance is highly variable, according to animal milk genetic potential and lactation stage, as well as to composition and nutrient density of the diet. When energy balance is negative, animals mobilize lipids stored in adipose tissues, mainly in the form of NEFA. As ruminant adipose tissues are very rich in palmitic, stearic, and oleic acids (see Bas et al., 1987, for goat tissues), this explains that 59% of the variability of milk C18:0 + C18:1 content (which represent from 15 to 45% of total milk FA) was linked to changes in energy balance, in goats with different milk yields, and receiving classic hay plus concentrate diets (without fat supplementation) during the first 4 mo of lactation (Figure 3). Correlations between the percentages of individual FA in these milks show three main families: C18-FA, C10 to C16-FA (negatively correlated to the C18-FA family), and C4 to C8-FA (not highly correlated to the two other families, with the exception of the negative correlation to C16:0) (Sauvant et al., 1973, and Figure 4). These correlations result mainly from the negative effect of long-chain (C18) FA that are mobilized from adipose tissue on de novo synthesis of medium-chain FA (C10 to C16; Barber et al., 1997), and from the fact that short-chain FA arise in part from metabolic pathways that do not involve malonyl-CoA and acetyl-CoA carboxylase activity (Bauman and Davis, 1974; Palmquist and Jenkins, 1980). Dietary factor (forage-to-concentrate ratio, type of forages, etc.) effects on goat milk composition have been reviewed by Morand-Fehr et al. (2000a). Dietary lipid supplementation is a means for increasing both energy intake and efficiency in early lactation-high yielding cows, thereby increasing milk yield, but it did not limit the mobilization of body lipids (Chilliard, 1993). Effects of lipid supplementation on goat milk secretion have been reviewed by Morand-Fehr et al. (1982) and Polidori et al. (1991). Feeding diets very low in lipids decreased goat milk yield and fat content, and this was reversed by lipid supplementation (Delage and Fehr, 1967; Morand-Fehr et al., 1984a, Table 1). In four early-lactation trials (Table 1), lipid supplementation tended to increase milk yield ( + 0.1 to + 0.4 kg/d or more when the control diet was very low in fat) and fat content ( + 2 to + 7 g/kg). Effects on protein content were highly variable. The calculated energy balance increased or decreased according to respective effects on intake of DM and energy, and milk fat secretion. In three other early-lactation trials, milk yield and protein content remained unchanged, and fat content increased, with either protected sunflower seeds (15% of concentrate; Morand-Fehr et al., 1984a), extruded soybeans (160 g/d; Morand-Fehr et al., 1984b) or calcium soaps of palm oil (100 g/d; Martin et al., 1999). There were no clear trends concerning effects of fat supplementation on goat BW changes or body fat mobilization during early lactation. Results from early-lactation experiments are limited by their lack of precision, linked to possible differences in milk potential of animals and limited use of covariates, when lipid supplementation begins before or immediately after parturition. Contrary to what was observed in dairy cows (Chilliard et al., 2001), feeding fat supplements to mid- or late-lactation goats did not increase milk yield, whereas milk fat content always increased sharply ( + 5.7 g/kg in 23 supplemented groups in Table 2). The ranges of observed responses were similar with different types of fat supplements: saturated free FA, calcium salts or triglycerides; animal fat; vegetable oils (C18:1-, C18:2-, or C18:3-rich oils; free oils, encapsulated oils); oilseed (whole, crushed, extruded, or formaldehyde-treated oil seeds) (Table 2, and Schmidely and Sauvant, 2001). Remarkably, goat milk fat content did not decrease even when vegetable oils (rich in polyunsaturated FA) were added to a low-forage diet (e.g., footnote 8 in Table 2), contrary to what was very clearly observed in dairy cows (Bauman and Griinari, 2001). As previously observed for early-lactation goats, response of milk protein content was highly variable in midlactation goats (Table 2). Body weight gain was either higher (Baldi et al., 1992), lower (Gelaye and Amoah, 1988), or unchanged (footnote 8 in Table 2) in fat supplemented vs. control goats. The response of dairy goats to fish oil supplements is not well known but differs from the responses to other fat supplements. Feeding unprotected fish oil to goats sharply decreased DMI and milk yield without changing milk fat content (Kitessa et al., 2001). This differs markedly from cow responses, where milk yield increased (despite a significant decrease in ...
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The purpose of this study was to assess the compositional features and microbiological quality of the milk produced by the autochthonous oasis goat in order to evaluate its suitability for cheesemaking. To attain this, two fresh cheeses with and without basil flavor were prepared and evaluated. One hundred milk samples were collected from multiparous lactating Arbi goats reared in the continental oasis region of Tunisia and processed into unflavored and basil-flavored cheese according to a traditional recipe. Milk samples were subjected to physical, chemical, and microbial analyses. The basic composition, mineral content, and bacterial profile of the cheeses were determined. In addition, the cheeses were subjected to organoleptic evaluation. The physical parameters of the analyzed milk were 6.54, 15.64, and 1030.89 for pH, acidity, and density, respectively. For the chemical properties of the milk, the results showed a respectable level of nutritional quality with a noteworthy content of dry matter, fat, protein, casein, and minerals, especially potassium, calcium, and phosphorous. With an average yield of 25%, the assessment of both cheeses illustrated good hygienic quality for all microflora examined, except total coliforms; a very noticeable organoleptic quality, as judged by all jury members; and satisfactory nutritional quality, with a significant protein and lipid level and a richness of mineral elements, particularly high levels of calcium and phosphorus. Basil-flavored cheese had the best aroma and taste, making it highly desirable to consumers. With the exception of coliforms and E. coli, the products bacteriological quality was acceptable and met legal requirements. The total absence of dangerous Salmonella and sulfite-reducing Clostridium strictly met the legal standards. The findings revealed the substantial chemical and nutritional value of milk and cheese made from local goats. However, additional studies are required to improve the microbial quality of the studied products.
... These parameters included conditions related to the nutrition of animals (e.g., grazing of animals, provision of concentrates), which is a significant determinant for the fat and the protein contents of the milk produced by sheep and goats [4,36]. The body condition score was also taken into account, as it reflects the nutrition of the animals [37,38] and it has also been associated with the quality of the milk produced by sheep [39]. ...
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... For instance, the average diameter of fat globules in goat milk is smaller, potentially enhancing digestibility [5,6]. Goat milk fat contains a higher proportion of medium-chain fatty acids (caprylic and capric acids) and branched-chain fatty acids, contributing to its distinctive flavor profile [7][8][9]. Moreover, medium-chain saturated fatty acids are more readily digestible and absorbable for infants compared to long-chain saturated fatty acids [10]. ...
Background: Goat milk has gained global attention for its unique nutritional properties and potential health benefits. Advancements in functional genomic technologies have significantly progressed genetic research on milk composition traits in dairy goats. Results: This review summarizes various research methodologies applied in this field. Genome-wide association studies (GWAS) have identified genomic regions associated with major milk components, with the diacylglycerol acyltransferase 1 (DGAT1) gene and casein gene cluster consistently linked to milk composition traits. Transcriptomics has revealed gene expression patterns in mammary tissue across lactation stages, while the role of non-coding RNAs (such as miRNAs and circRNAs) in regulating milk composition has been confirmed. Proteomic and metabolomic studies have not only helped us gain a more comprehensive understanding of goat milk composition characteristics but have also provided crucial support for the functional validation of genes related to milk components. The integration of multi-omics data has emerged as an effective strategy for elucidating complex regulatory networks from a systems biology perspective. Conclusions: Despite progress, challenges remain, including refining reference genomes, collecting large-scale phenotypic data, and conducting functional validations. Future research should focus on improving reference genomes, expanding study populations, investigating functional milk components, exploring epigenetic regulation and non-coding RNAs, and studying microbiome–host genome interactions. These efforts will inform more precise genomic and marker-assisted selection strategies, advancing genetic improvements in milk composition traits in dairy goats.
... In addition to the profile of individual FA with each diet, the proportion of beneficial FA was also calculated using the following parameters: PUFA/SFA ratio values; proportion of desired fatty acids (DFA); HSF (hypercholesterolemic SFA) and hypocholesterolemic/hypercholesterolemic (h/H) ratio. The nutritional quality of milk and cheese fat was also assessed by the calculation of health indices: the atherogenic index (AI), calculated according to [24], and the thrombogenic index (TI), calculated following [25]. ...
... The increased lactose levels could also be attributed to a higher glucose availability for lactose synthesis in the mammary gland as a result of feeding with these lipid-enriched diets. This effect was presented by other researchers [24] in goats fed starch-enriched or lipid-supplemented diets. Tudisco [8] also reported an increase in lactose content for goat fed linseed (4.61%) compared with pasture-fed goat (4.57%). ...
The study aimed to assess the effects of including linseeds or hempseeds in the diets of late lactation Murciano-Granadina dairy goats on the nutritional quality of the milk and cheese fat, expressed by the fatty acids profile and the healthy lipid indices. Thirty-six goats were randomly distributed in 3 groups of 12 animals each, according to a 3 × 3 Latin square design, and fed three different diets: group CON (control, with sunflower meal, 11.5% DM basis); group LIN, where sunflower meal was replaced by linseed; and group HMP, where sunflower meal was replaced by hempseeds. The replacement had no effects on the milk yields and the milk protein content as no significant differences were detected among groups. The significant increase of the fat content in the case of the LIN and HMP groups was accompanied by significant decreases in saturated fatty acids concentration and very significant increases in monounsaturated fatty acids. The content of n3 and n6-PUFAs (polyunsaturated fatty acids) increased, mainly due to a 4.1 times higher proportion of alpha-linolenic acid (ALA; C 18:3n-3) in LIN diet milk and a 1.3 times higher proportion of linoleic acid (LA; C 18:2n6c) in HMP diet milk. The conjugated linoleic acid (CLA; isomer c9, t11) was 1.9 times higher for the LIN diet and 5.05 times higher for the HMP diet. Feeding either linseed or hempseeds contributed to the reduction of the atherogenic and thrombogenic indices, increased the hypocholesterolemic: hypercholesterolemic ratio as well as the proportion of other desired fatty acids in the milk fat. The improved nutritional quality of milk, which has potentially far-reaching human health benefits, is maintained in cheese through the increase of the n3 and n6-PUFAs, especially for the LIN diet where the n6/n3 ratio decreased significantly, compared with the CON diet (3.62 vs. 6.88). The CLA concentration was significantly higher (p < 0.001) for the HMP cheese compared with the CON diet (1.89% vs. 0.78%). These effects highlight the opportunity of obtaining dairy products with improved nutritional quality using local feed resources.
... Since short-chain FAs are considered hypercholesterolemia (Chilliard et al., 2014), producing milk with a reduced content of these FAs, the use of supplemental SFO could be interesting for the dairy industry. It is noteworthy that both the quantity and physical form of vegetable oils in the diet (Chilliard et al., 2003;Nudda et al., 2014;Nudda et al., 2020;Leduc et al., 2021), as well as their interactions with other dietary components and supplements (Cieslak et al., 2010), may influence the milk fatty acid profile concentration in sheep and goats, potentially acting as a source of heterogeneity in the present study. Therefore, these factors should be taken into account in the development of feed strategies at both farm and industry levels, as well as in the research process, to decrease the noise effect by considering them as covariates when feasible. ...
Milk and dairy products are important foods that contribute to daily nutrient requirements and improve consumers’ health. The objectives of this study were to critically review and quantify, using meta-analysis and meta-regression, the effects of supplementation with sunflower oil (SFO) on dry matter intake (DMI), milk yield (MY), components and fatty acids (FAs) profile in dairy goats. A total of 154 papers were reviewed. Nine articles (10 experiments) met the eligibility criteria and were used in the analysis. The effect size for all parameters was calculated as raw mean difference (RMD) and standardized mean difference (SMD). Heterogeneity was determined using I 2 statistics, while meta-regression was used to examine factors influencing heterogeneity. Responses to SFO supplementation were heterogeneous for all variables studied. However, SFO decreased DMI (RMD = -0.050 kg / d; p = 0.007) and increased milk fat percent (MFP; p < 0.001) and milk lactose percent (MLP; p < 0.001), but the effect size was not significant for MY. The inclusion of SFO in dairy goats rations enhanced C18:1 cis-9 (RMD = +2.22 g / 100 g FA; p < 0.001), C18:1 trans-11 (RMD = +2.77 g / 100 g FA; p < 0.001), C18:2 cis-9 trans-11 (RMD = +0.261 g / 100 g FA; p < 0.001), C18:3 n-3 (RMD = +0.078 g / 100 g FA; p = 0.002) and MUFA (RMD = +7.16 g / 100 g FA; p = 0.002) and PUFA (RMD = +1.49 g / 100 g FA; p < 0.0001), and diminished SFA (RMD = -7.53 g / 100 g FA; p = 0.008). Overall, the meta-analysis data indicated that dietary SFO supplementation in dairy goats has a positive effect on desirable milk components for human consumption. However, a cost-effectiveness analysis is needed to provide accurate recommendations to farmers and the dairy goat industry.
... The increment trend of milk protein content in this study was similar with a study by Zailan et al. (2023) in its study of feeding treated-EFB to the dairy goats, which signi cantly increase milk protein content. It has also been observed by Chilliard et al., (2003) in its review studies that the addition of fat to the goat diet not only causes no reduction in milk protein The current study results were similar to a previous study by Chamberlain and DePeters (2017) where high content of palmitic acid in milk was found and it was due to the high content of palmitic acid in the diet. The current study observed a signi cant increment of milk fatty acid occurs at medium-chained fatty acid, which is capric acid, lauric acid, and myristic acid that originated from de novo synthesis in the mammary gland where acetate and β-hydroxybutyrate are the major substrate sources. ...
... This is because when the energy balance is negative, animals mobilise lipids stored in adipose tissue, mainly in the form of non-esteri ed fatty acid (NEFA). Since ruminant adipose tissues are in high content of palmitic, stearic and oleic acid as described by Bas et al., (1987) in goat tissues, 59% of the variability in milk content of C18 and C18:1 is related to energy-balanced changes, in goats with differences in milk yield during the rst four months of lactation, fed with a classic diet of hay and concentrate diet (Chilliard et al., 2003). A lower UFA: SFA ratio was observed in milk of EFB feed due to a higher proportion of SFA content in the milk. ...
The effect of feeding empty fruit bunch extract on milk production and milk fatty acid profiles of lactating Saanen goats was evaluated. A total of four lactating Saanen goats (14 days in milk, 54.3 ± 9 kg of body weight) were subjected to a crossover design with a 17-d period (10-day adaptation period and 7-day for data and sampling period) with a 12-day washout period in between both periods. The treatment diets were; CON; (0% extract, basal diet of 60:40 of napier grass and concentrate) and EFB (5% OPEFB extract per DM basal diet). The 5% EFB extract in EFB diet did not affects milk yield, milk fat, milk total solid and milk solid non-fat compared to the CON diet. The milk protein content was significantly higher in EFB diet (P < 0.05) while milk lactose content was significantly higher in CON diet (P < 0.001) when compared to the others. Milk from EFB diet shows significantly higher (P < 0.05) in capric, lauric, myristic acid, and total SFA concentration as compared with milk from CON diet. Goat fed with EFB diet significantly reduced (P < 0.05) in stearic, oleic, total UFA, total MUFA concentration and UFA: SFA ratio in milk when compared with goat fed with CON diet. Meanwhile, the content of myristoleic acid, linoleic acid and PUFA: SFA ratio was similar between both treatment diets. Hence, the supplementation of 5% OPEFB extract in EFB diet did not alter milk production but the composition of the milk especially the profiles of milk fatty acid.
... Furthermore, it is observed that some components of the milk produced by the goats of the three groups showed variations over time during the first 60 days of lactation (p=0.02). With higher values for goats supplemented with bypass fat compared to GCON; That is to say, there was a positive effect of supplementation on the best quality of milk (fat), with respect to the goats they did not receive bypass fat in the daily ration, a situation like that reported by (Shingfield et al., 2010) who evaluated the effect of trans fatty acids in the nutritional regulation of mammary lipogenesis in ruminants and report that the variation in the secretion of mammary fatty acids and lipogenic responses to changes in diet composition among ruminants reflects species-specific differences in metabolism. of rumen lipids, which is why the use of a protected fat promotes mammary lipogenesis in goats, fat being the most important component that contributes to the organoleptic, physical and processing properties of ruminant milk (Chilliard et al., 2003;Park et al., 2007;Markovic et al., 2020;Hammam et al., 2022). In this sense, in our study the GHP95 goats received 100 g of bypass fat with 95% palmitic acid, which is a long-chain saturated fatty acid and represents one of the most common saturated fatty acids in animals, plants and microbes. ...
Background: Lactating goats show a negative energy metabolism, which is why supplementation during this period is beneficial for the female, improving the production and chemical composition of milk. Various studies have shown that the use of protected fats in ruminants increases the quantity and quality of milk. The objective of the study was to evaluate the effect of a bypass fat on milk production and quality in grazing goats. Methods: In an extensively managed goat herd in the Comarca Lagunera, goats (n=30) were selected and distributed in 3 treatments: (GCON), this group only consumed the vegetation in the grazing sites, (GHP95) this group received grazing plus bypass fat and (GLM45) this group received grazing plus bypass fat, the supplementation with bypass fat was 100 g/goat/d. During the study, live weight, body condition, milk production and quality were determined. Result: The research shows that supplementation with bypass fat is sufficient to increase production (p<0.05) and quality of milk (fat; p<0.05) after calving in the different samplings (p<0.05). The results favored GHP95. This supplementation makes the use of protected fats in animal feed more efficient, increasing productive parameters and income for grazing goat producers.
... Similar results have been reported in several studies (Talpur et al., 2009;Mierlita et al., 2011a;Payandeh et al., 2016). These differences observed between Najdi and Awassi breeds could potentially be due to differences in acetyl-CoA carboxylase activity in mammary cells and a resulting increased de novo synthesis of polyunsaturated fatty acids (Chilliard et al., 2003;Bernard et al., 2005). ...
The breed of dairy sheep is an important factor affecting milk quality. The aim of this study is to identify the fatty acids (FA) and indices of lipid quality of milk fat in two indigenous Saudi sheep breeds. In this study, thirty-one multiparous ewes of Najdi (n=16) and Awassi (n=15) were examined. The breeds were kept under identical conditions and provided with the same feed (alfalfa hay and commercial pellets). After weaning at 9 to 12 weeks, ewes were milked twice daily until the end of lactation. Duplicate samples were taken from each ewe at weeks 9 and 10 for analysis of FA using a GC mass spectrometer. The collected data were analyzed using the SAS 9.4 program as a general liner modal (GLM) method. Najdi ewes produced more milk than Awassi ewes (0.75 vs. 0.63 L/day; P ≤ 0.01), while milk components were not influenced by breed. The milk fat of Awassi ewes had higher content of saturated fatty acids (SFA: 59.2%), monounsaturated fatty acid (MUFA: 35.9%), and polyunsaturated fatty acid, (PUFA: 5.06%). Compared to the Najdi breed, the milk from Awassi ewes had a higher of conjugated linoleic acid (CLA), content with values of 0.72% compared to 0.56% in the milk of Najdi ewes. The atherogenic and thrombogenic indices of milk fat varied between 1.52% and 1.79% with sufficiently low values (less than 3%). The milk fat of the Awassi breed had a higher omega-3 (n3) ratio (0.94 vs. 0.54%), a lower n6/n3 ratio (3.77 vs. 7.39%) and a lower Hypocholesterolemia index value (33.6 vs. 36.9%) compared to Najdi's milk fat. These results showed that breed had a significant impact on milk quality, particularly essential fatty acids (CLA and ALA). The importance of selecting the Awassi breed in sheep breeding for the production of the milk with a slightly more favorable FA and lipid quality. This milk can potentially contribute to a healthier diet and improve the overall well-being of consumers.
