Influence of genotype, parity, and lactation stage on fatty acid profile and quality traits of Ewe milk

Various management practices can influence milk quality traits in dairy cattle. As an example, an increasing investment in automatic milking system to substitute milking parlors has been observed in the last 2 decades in dairy farms which could have affected certain bulk milk quality traits. What is more, milking practices can also affect certain milk parameters; as an example, teat disinfectants containing I are used in commercial farms where pre- or postdipping is performed, leading to presence of some I in the bulk milk. However, this trace mineral is also supplied in cows' diet to fulfill their nutritional requirements, partly contributing to the milk I final concentration. Therefore, the aim of this study was to evaluate the sources of variation of milk I along with other traditional milk quality traits. A total of 91 dairy farms in northeastern Italy were enrolled in the study. In each farm, diet and bulk milk samples were collected on the same day for chemical analysis. Concentration of I, in particular, was determined in both milk and feed with gold standard. Pearson correlations were calculated among the traits available for milk and diet, and a general linear model was used to test significance of fixed effects (feeding system, milking system, farming system, herd size, herd stage of lactation, and sampling month) on milk quality traits including the I concentration. In the case of milk I, diet I and presence of I-based predipping and postdipping teat disinfect application were also tested as fixed effects. Results showed a positive linear correlation between milk and diet I content (correlation coefficient [r] = 0.78). Although milk I was also positively correlated with lactose content (r = 0.25), dietary I was not correlated with other milk traits. Milk I content was significantly affected by dietary I, I-based predipping teat disinfectant application, and herd composition. Compared with conventional farms, organic farms showed lower protein content and greater somatic cell score (SCS) but similar milk I. Milking system significantly affected only lactose content and SCS of milk. Sampling month was only significant for milk urea nitrogen and herd composition, feeding system, herd size, and herd average days in milk did not modify milk gross composition and SCS. In conclusion, dietary supply of I is the main factor affecting milk I concentration and findings suggest that I level in milk can be naturally improved in dairy cows by modulating the I content in the diet administered. However, further research is needed to evaluate the effect of I-based sanitizers on milk I.

Simple SummaryThe buffalo dairy industry has deep roots in Southern Italy, due to the traditional link with Mozzarella di Bufala, a Protected Designation of Origin cheese with high economic value and market demand. At farm level, strategies aiming to improve milk yield and quality are essential to maximize profitability and dairy chain efficiency. In this study, we analyzed a large data set of Italian Buffaloes (around 70 thousands animals) in order to detect the phenotypic sources of variation of milk yield and quality traits, disclose exploitable favorable correlations among milk traits, and provide useful information for dairy buffalo chain stakeholders.The buffalo milk industry has economic and social relevance in Italy, as linked to the manufacture of traditional dairy products. To provide an overview of the current status of buffaloes’ performances on a large scale, almost 1 million milk test-day records from 72,294 buffaloes were available to investigate milk yield, energy corrected milk, fat, protein, and lactose content, and somatic cell score (SCS). Phenotypic correlations between milk traits were calculated and analysis of variance was carried out through a mixed model approach including fixed effect of parity, stage of lactation, sampling time, month of calving, and all their interactions and random effects of buffalo, herd-test-date, and residual. Third-parity buffaloes were the most productive in terms of milk yield, while the lowest solid content was detected in sixth parity buffaloes. A considerable gap between primiparous and multiparous buffaloes was observed for milk yield, especially in early- and mid-lactation. Overall, SCS progressively increased with parity and showed a negative correlation with milk yield in both primiparous (−0.12) and multiparous (−0.14) buffaloes. Results suggested that, at the industrial level, milk of primiparous buffaloes may be preferred for transformation purposes, since it was characterized by greater solid content and lower SCS. Results of this study provide a picture of the Italian population of buffaloes under systematic performance records and might be beneficial to both dairy industry and breeding organizations.

The quality of milk is fundamental to producing safe milk and dairy products that are suitable for consumption. The objective of this study was to determine the influence that the content of dietary polyunsaturated fatty acids (PUFA) has on the total mixed ration (TMR) and lactation stage of milk’s composition and the fatty acid profile (FA) of the dairy Najdi breed. During the lactation period, 48 Najdi ewes used the following four treatments: traditional feed (TR) and three total mixed rations (TMR1, TMR2, and TMR3) with different PUFA content. Milk samples were taken from whole milk in the morning. The chemical composition and FA profile were analyzed. The results show that the ewes fed TMR1 with a PUFA content (25.20%) produced high-quality milk as they contained high levels of polyunsaturated fatty acids (PUSF), linoleic acid (LA), α-linolenic acid (ALA) and omega-3 (n3). On the other hand, the milk of ewes fed TMR2 with PUFA (15.06%) contained high levels of unsaturated fatty acids (USF) and monounsaturated fatty acids (MUFA) and had significantly reduced hypercholesterolemia (HFA). It can be concluded that milk fat, protein, and total solids in the milk of Najdi sheep increased as lactation progressed, while lactose remained constant. Furthermore, as lactation progressed, saturated fatty acids (SFA), stearic acids, and oleic acids (OA) increased while USF and MUFA decreased. TMR diets can directly benefit the producer and livestock by producing high-quality milk while reducing its economic value.

This study aimed to survey milk yield, lactation stages and milk quality traits of Damascus goats reared underdifferent feeding systems. Goats were divided according to feeding systems as pasture based and concentrate based. Feeding systemswere found to have significant effect on lactation milk yield but not on lactation duration. Although differences between feedingsystems were not found significant on pH, milk composition factors (fat, lactose, dry matter), somatic cell count and malondialdehyde(except for early lactation stage) for each lactation stage, significant effects were detected on same parameters among lactation stages.Calcium levels at early lactation stage in milk differed either between feeding systems or among lactation stages. Also, other mineralswere found to decrease with lactation. While most of the fatty acids were affected in any of the lactation stages by the feeding system,all of them were significantly altered by lactation stages. Pastured goats had a lower percentage of total saturated fatty acids, atherogenicindex, thrombogenic index and odour index ratios. In accordance with milk fatty acid composition, compared to the milk obtained fromgoats fed with concentrate, the milk obtained from the goats that pastured was healthier and early lactation stage was found to producehealthier milk than late lactation stage.

An amino acid substitution (K232A) in the enzyme diacylglycerol acyl-CoA acyltransferase 1 (DGAT1) has been reported to explain variation in milk traits and milk fatty acid (FA) profile. In this study, associations between K232A, and milk traits including milk FA composition, were studied in wholly pasture-fed New Zealand Holstein-Friesian × Jersey cross-bred (KiwicrossTM) dairy cows. With a high frequency of K variant (61.9%), the KK cows produced more milk fat on average (5.41 ± 0.04%), than the AA cows (4.43 ± 0.06%). The milk volume, fat concentration and protein concentration for the AK cows were between the values for the genotypes AA and KK. More C16 : 0 (saturated fatty acid), conjugated linoleic acid (CLA) and polyunsaturated fatty acid (C18:3 cis-9, 12, 15) were found in the milk of the KiwicrossTM cows, and the influence of DGAT1 K232A on these FAs during the mid- and late- stage of lactation were significant. The AA cows produced more (P < 0.001) CLA (1.137 ± 0.047 g/100 g) and C18:3 cis-9, 12, 15 (0.855 ± 0.015 g/100 g), but less C16:0 (35.170 ± 0.355 g/100 g) than the KK cows (0.934 ± 0.025 g/100 g, 0.778 ± 0.009 g/100 g and 38.010 ± 0.250 g/100 g respectively).

The use of 2-dimensional gas chromatography to investigate the effect of rumen-protected conjugated linoleic acid, breed, and lactation stage on the fatty acid profile of sheep milk

Information on fatty acid (FA) profile is critical for the production and promotion of sheep milk and derivative dairy products. The presence of the essential ω-3 and ω-6 FA in milk fat as well as other less common FA, like linoleic acid isomers, has gained an increasing interest due to the consumer demand for a healthy diet. This research assesses the FA profile and estimates the lipid quality indices (ratio between hypocholesterolaemic and hypercholesterolaemic fatty acids, peroxidisability index, atherogenic index, and thrombogenic index) of raw milk and cream fat from two indigenous Greek sheep breeds (Karagouniko and Chios) at different lactation stages. Raw milk and cream fat presented a favorable ω-6/ω-3 ratio below 4:1. Atherogenic and thrombogenic indices of all studied milk fat fluctuated in sufficiently low levels (<3). The FA profile and lipid quality indices in both raw milk and cream samples differed significantly depending more on the lactation stage compared to the breed type. Raw milk fat from late lactation had more beneficial fatty acid profile compared to early and middle lactation stages. Differences among breeds were highlighted when raw milk and cream samples were compared within the same lactation stage. Raw milk and cream fat from Karagouniko breed were characterised by higher ω-3 proportion, lower ω-6/ω-3 ratio and lower thrombogenic index value compared to those from Chios breed.

Simple SummaryAs mare’s milk has high nutritional and biological value, it has a number of therapeutic properties. The aim of this study was to determine the basic composition, fatty acid profile, and values of health-related indices of milk from mares of different lactation stages, ages, and birth orders. The study was conducted on milk obtained from Coldblood mares in weeks 10, 15, and 25 of lactation. The mares were aged between five and 14 years. It was found that milk produced from the 15th week of lactation had the most beneficial fatty acid composition and very beneficial values of health-related indices (low values of the atherogenic index—AI and thrombogenic index—TI), which is important with regard to the prevention of atherosclerosis and thrombosis. Moreover, the study found a dependence between birth order and the atherogenic index, which was lower in milk derived from older mares (birth order > 7). The findings from the study indicate that it is possible to modify the fatty acid profile of milk by appropriately managing the age structure of the herd of mares, among other things. To confirm this dependence, the study will be continued on a larger group of mares.The objective of this study was to determine the chemical composition, fatty acid profile, and values of healthy indices of milk from a specialized farm of Polish Coldblood mares of different ages, birth orders, and lactation stages. Milk samples (n = 48) were collected for analysis in weeks 10, 15, and 25 of lactation from mares aged between five and 14 years. The study showed that the stage of lactation has a significant effect on the fatty acid (FA) profile of the milk produced on the farm. The highest concentration of monounsaturated and polyunsaturated FAs was found in milk produced from the 15th week of lactation. The milk was also characterized by low values of atherogenic and thrombogenic indices, which indicate the health benefits of milk with respect to the content of fatty acids and their potential to prevent or cause atherosclerosis and thrombosis. The study also found a significant correlation between the number of foalings (birth order), the fatty acid profile, and atherogenic index of milk produced on the farm. The findings from the study indicate that it is possible to modify the fatty acid profile of bulk tank milk through appropriate management of the age structure of the herd of mares. To confirm this dependence, the study will be continued on a larger group of mares.

Simple SummaryThe substitution of soybean meal in farm animal diets is considered vital for the economic and environmental sustainability of the livestock sector. However, data regarding the effects of a soybean meal replacement on the milk yield and quality traits in dairy sheep are scarce. In our study, two isonitrogenous and isoenergetic diets were used, with soybean meal of a typical ration being replaced by a mixture of rapeseed meal, cottonseed cake, and fava beans. The milk yield and the body condition scores were recorded, and milk samples were analyzed monthly for their fat, protein, lactose, and total solids yields, as well as for somatic cell counts, total bacterial counts, pH, electrical conductivity, and the refractive index. Daily and 100-day fat yields were significantly increased in the group fed the experimental ration and the electrical conductivity was significantly decreased in the same group, while no adverse effects on any of the rest of the studied milk production traits were observed.The replacement of soybean meal (SBM) from intensively reared dairy sheep diets has emerged as a significant challenge for sustainable production. However, the effects of this replacement on milk production have not been sufficiently elucidated. The objective of this study was to prospectively assess the effects of replacing SBM with a mixture of alternative protein sources on the milk yield (MY) and the milk quality traits (MQT) in intensively reared dairy sheep. A total of 112 multiparous, purebred milking ewes of the Chios and Frizarta breeds, from two intensive dairy sheep farms, were involved in the study, postweaning, and were assigned to either the control (CR) or the experimental ration (ER) group. In the ER, 3/4 of the SBM was replaced by a mixture of rapeseed meal, cottonseed cake, and fava beans, producing a ration of a similar nutritional value. MY, MQT, and body condition scores were recorded for each individual ewe monthly for a period of 4 months during lactation. The experimental ration was associated with beneficial effects on daily and 100-day fat yields and on the electrical conductivity of milk as an improved udder health status indicator, with no adverse effects on any of the rest of the studied milk production traits.

Milk yield, quality, and coagulation properties of 6 breeds of goats: Environmental and individual variability

Simple SummaryCreole goat milk is a valuable product for human consumption. Its physicochemical characteristics could be influenced by altitude and lactation stage. In this work, we evaluated several chemical and physical conditions of Creole goat milk in semiarid rangeland. The main results indicated that protein and density are influenced by altitude, while fat, freezing point, and pH are influenced by the lactation stage. One of the most nutritional values of goat milk is the type and concentration of fatty acids. In this work, we found that the effect of the agroecological region was minimal on their concentration. The lactation stage affected the composition of medium-chain fatty acids and linoelaidic acid. We concluded that nutrition by altitude and goat genetic background could contribute to milk composition.Goat milk composition is affected by feeding, and in semiarid rangeland, information on Creole goat milk physicochemical composition is lacking. For the fulfillment of this objective, three agroecological regions (AR) considering altitude (lowland 87, highland 779, and mountain 1309 m above sea level) with different botanical compositions were chosen. Every AR analyzed accounted for 30 goat herds, with a total of 90 herds. The results demonstrated that altitude had an influence mainly on density and protein. Milk density increases as altitude increases; conversely, milk protein increases as altitude decreases. On the other hand, in the mountain and lowland ARs, the salts and solids not fat (SNF) percentages were higher compared to that of the highland AR (p < 0.05). The freezing point (FP) was higher at highland altitudes compared to that of mountain and lowland ARs (p < 0.01). In the milk fatty acids (FA) profile, only the C14:1 value was affected by altitude, whereas goat milk at lowland and mountain altitudes had higher values compared to that at highland altitudes (p < 0.05). Additionally, late lactation stage fat, FP, and pH values were higher compared to early lactation values. The opposite effect was observed for salts and SNF. In the FA profile, late lactation values were higher for C10:0 and C8:0 compared to early lactation values. The opposite trend was observed for C18:2n6t. The thrombogenic index was significantly higher at lowland altitudes compared to highland altitudes, and similar to the mountain AR. These goat milk characteristics could be explained as a consequence of animal nutrition, as well as the goat’s meat-type phenotype.

This trial aimed to study the changes in the yield, composition, and fatty acid (FA) profile of ewes’ milk during suckling and milking periods. Nineteen multiparous Najdi ewes were kept under identical management and feeding conditions during a 12-week trial that was divided into two periods. Milk samples were collected on each sampling day from the total yield during the suckling (3rd, 6th, and 9th week) and milking (12th week) periods. The milk yield and the total solids, fat, protein, and lactose contents of the milk remained constant throughout the suckling weeks, but the protein content increased and milk yield and lactose content decreased after weaning. There were no differences in milk saturated FA (SFA), unsaturated FA (UFA), and monounsaturated FA (MUFA) contents during the suckling and milking periods, whereas the polyunsaturated FA content increased during the milking period. There were no differences in the individual milk SFA during the weeks of suckling, but the contents of caproic acid (C6:0), caprylic acid (C8:0), margaric acid (C17:0), and stearic acid (C18:0) decreased. However, myristic acid (C14:0), lauric acid (C12:0), and isomers of pentadecanoic (C15:0) acid increased during the milking period. The percentage of vaccenic acid (C18:1 △ 11 t ), rumenic acid (C18:2 △ 9 c ,11 t ; conjugated linoleic acid (CLA)), ω-3 FA group, and the atherogenicity index did not differ during the suckling period, but increased after weaning in the 12th week of lactation. This study demonstrated that weaning lambs in Najdi ewes is probably a factor that strongly affects milk traits by changing yield, composition, and FA profile. Keywords: CLA, dairy ewes, milk fat, milk yield, stage of lactation

Effects of training of Saanen goats for the first milking on behavior, milk yield, and milk quality traits

Associations between differential somatic cell count and milk yield, quality, and technological characteristics in Holstein cows

Sheep fed only silage or silage supplemented with concentrates: 2. Effects on lamb performance and fatty acid profile of ewe milk and lamb meat