Milk Protein Composition Research Articles

Influence of stage lactation on quality and protein compositions of Kazakh mare milk and koumiss

Limited studies have examined the effects of geography, climate, and lactation on mare's milk in Kazakhstan. The study aimed to assess the protein components and quality of mare's milk and koumiss from 24 mares in southern Kazakhstan. Milk samples were collected monthly between July and December 2023. The soluble protein fraction was analysed via SDS-PAGE. Casein fractions were examined using SDS-PAGE polyacrylamide electrophoresis. The results indicated the presence of α-, β-, and κ-caseins, along with whey proteins such as α-lactalbumin and β-lactoglobulin in the milk and fermented products. The milk contained 9.02% total solids, 1.62% protein and 1.22% casein on average. The mare milk fat content was 0.71% in Almaty, and in the Zhambyl region, it was significantly higher - 1.24%. The fermented koumiss products had a fat content of 1.22% in Almaty, while in Zhambyl, it was significantly higher at 1.94%. Similarly, the casein content in the Zhambyl region was 1.38%, compared to 0.81% in Almaty. The results indicate that different zones significantly affect mare's milk's fat and protein composition.

Cow Milk Fatty Acid and Protein Composition in Different Breeds and Regions in China.

Cow milk is rich in proteins, fats, carbohydrates, and minerals; however, its precise nutrient content varies based on various factors. In the current study, we evaluated the differences in the fatty acid and protein contents of milk and the factors associated with these differences. To achieve this, samples were collected from seven types of cows in different regions. These included samples from three dairy breeds: Chinese Holstein milk from Beijing, China (BH), Chinese Holstein milk (HH) and Jersey milk (JS) from Hebei province, China; and four dairy/meat breeds: Sanhe milk (SH) from Inner Mongolia Autonomous Region, China, Xinjiang brown milk (XH) and Simmental milk (SI) from Xinjiang Uygur Autonomous Region, China, and Shu Xuanhua milk (SX) from Sichuan province, China. Breed significantly affects total fat, fatty acid, and protein contents. Additionally, geographic region significantly affects the contents of different fatty acids, α-lactalbumin, and lactoferrin. JS has the highest total fat and casein contents. XH samples contain significantly higher unsaturated fatty acid content than BH samples and do not differ significantly from JS. Additionally, the low β-lactoglobulin and high lactoferrin contents in XH samples may be favorable for the growth and development of infants. Our results may inform the development of dairy products from different cow breeds and advance the process of accurate breed identification.

The influence of zootechnical factors on the composition of proteins in raw cow's milk

The scientific review is devoted to the current problem of the quality of raw materials in the production of dairy products. The purpose of the research is to update scientific data on the influence of zootechnical factors on the protein composition of raw cow›s milk. In the context of the development of the specialized nutrition market, an in-depth study of milk proteins is necessary as the most important source of essential amino acids. The authors reviewed the scientific works of domestic and foreign specialists, covering the influence of various factors on the protein composition of raw cattle milk. During the formation of the scientific review, the factors studied were divided into the following groups: selection-genetic, feed, temporal, zoohygienic and technological. This made it possible to determine the degree of influence of factors on milk quality indicators, especially proteins, and to trace their dependence on each other.

Genome-wide association studies for milk production traits in two autochthonous Aosta cattle breeds

Genome-wide association studies (GWASs) are used to identify quantitative trait loci for phenotypic traits of interest. The use of multilocus mixed models allows to correct for population stratification and account for long-range linkage disequilibrium. In this study, GWASs were conducted to identify the genetic bases of milk production (milk yield, protein and fat composition, and yield) in two autochthonous dual-purpose cattle breeds from the Aosta Valley. Using either the breeding values or the deregressed proofs, common significative single nucleotide polymorphisms have been identified for milk yield, protein percentage, and fat percentage. Two major quantitative trait loci regions have been identified on the chromosomes 5 and 14 for the fat percentage, harbouring the MGST1, CYHR1, VPS28, and CPSF1 genes. For the protein percentage, a candidate region has been identified on BTA 6; in this region, the CSN1S1, CSN2, HSTN, CSN3, and RUFY3 genes are annotated. Most of the identified genes have already been associated with milk composition in other studies on cosmopolitan and local cattle. These results show that the genes involved in milk composition quantitative traits in the Aosta cattle are common also in other cattle breeds and they can be further investigated with the use of whole genome sequencing data.

Goat Milk Allergy and a Potential Role for Goat Milk in Cow's Milk Allergy.

In many parts of the world, goat milk has been part of the human diet for millennia. Allergy to goat's milk, not associated with allergy to cow's milk, is a rare disorder, although some cases have been described. Goat milk proteins have substantial homology with cow's milk proteins and even show cross-reactivity; therefore, they are not advised as an alternative to cow's milk for infants with IgE-mediated cow's milk allergies. However, there are indications that, due to the composition of the goat milk proteins, goat milk proteins show lower allergenicity than cow's milk due to a lower αS1-casein content. For this reason, goat milk might be a better choice over cow's milk as a first source of protein when breastfeeding is not possible or after the breastfeeding period. Additionally, some studies show that goat milk could play a role in specific types of non-IgE-mediated cow milk allergy or even in the prevention of sensitization to cow's milk proteins. This review discusses a possible role of goat milk in non-IgE mediated allergy and the prevention or oral tolerance induction of milk allergy.

Protein and oligosaccharide composition of colostrum and transition milk from pasture-based dairy cows supplemented prepartum with inorganic selenium, organic selenium or rumen-protected choline

Prepartum diet and mineral supplementation can influence bovine colostrum proteins and oligosaccharides (OS). The objective of this study was to evaluate the effects of prepartum supplementation with 1) inorganic selenium (INORG), 2) organic selenium (ORG) or 3) rumen-protected choline (RPC) on these components. Fifty-seven (12 primiparous and 45 multiparous) cows were supplemented daily from 49 ± 12.9 d prior to calving until d of calving. Colostrum was collected within 1 h postpartum and transition milk (TM) samples 1–5 were collected over the following 2–3 d postpartum. Prepartum supplementation with INORG, ORG or RPC had no significant effect on the gross, OS or IgG composition of colostrum. Animals supplemented with ORG or RPC produced significantly higher concentrations of colostrum αs2-Casein and β-Casein. Each milking postpartum had a significant effect on the protein and OS composition of milk. This research demonstrates that supplementing these micro-nutrients prepartum does not have a deleterious effect on subsequent colostrum or TM composition.

Milk Yield, Composition and Growth of Kids of West African Dwarf Does Fed Enterolobium Cyclocarpum Leaves

The aim of this experiment was to determine the milk yield, composition and the growth performance of kids of West African dwarf (WAD) does fed varying levels of Enterolobium cyclocarpum (EC) leaves. Twelve lactating goats at their first parity were used in a completely randomized design. The does were divided into 4 groups and fed diets containing 0 %. 07.50 %, 15.00 % and 22.50 % Enterolobium cyclocarpum leaves in a concentrate diet respectively. The experiment commenced at the fourth month of pregnancy till the 56th day post-partum. Milk yield was significantly (p<0.05) highest (196.10 g) for does fed Diet 2 with 07.50 % EC leaves. Milk yield for does fed other diets followed this order: 184.35 g (Diet 1) > 104.13 g (Diet 3) > 101.79 g (Diet 4). Milk protein composition ranged from 3.34 – 5.97 % and was significantly (p<0.05) highest (5.97 %) in the milk of does fed Diet 3 (15.00 % EC leaves). Milk magnesium concentration ranged from 18.87 mg/100g (Diet 1) to 24.00 mg/100g (Diet 2) while sodium ranged from 11.88 mg/100g (control) to 20.06 mg/100g (Diet 2). The concentrations of magnesium (24.00 mg/100g) and sodium (20.06 mg/100g) were thus significantly (p<0.05) highest in the milk of does fed Diet 2 (07.50% EC leaves). Diet 2 also supported maximal growth weight (4,858.50 g) of kids at the 9th week. Thus WAD does should be fed 07.50% Enterolobium cyclocarpum leaves for maximal milk yield and kids growth.

Comparison of miR-106b, miR-191, and miR-30d expression dynamics in milk with regard to its composition in Holstein and Ayrshire cows.

Milk composition varies considerably and depends on paratypical, genetic, and epigenetic factors. MiRNAs belong to the class of small non-coding RNAs; they are one of the key tools of epigenetic control because of their ability to regulate gene expression at the post-transcriptional level. We compared the relative expression levels of miR-106b, miR-191, and miR-30d in milk to demonstrate the relationship between the content of these miRNAs with protein and fat components of milk in Holstein and Ayrshire cattle. Milk fat, protein, and casein contents were determined in the obtained samples, as well as the content of the main fatty acids (g/100 g milk), including: saturated acids, such as myristic (C14:0), palmitic (C16:0), and stearic (C18:0) acids; monounsaturated acids, including oleic (C18:1) acid; as well as long-, medium- and short-chain, polyunsaturated, and trans fatty acids. Real-time stem-loop one-tube reverse transcription polymerase chain reaction with TaqMan probes was used to measure the miRNA expression levels. The miRNA expression levels in milk samples were found to be decreased in the first two months in Holstein breed, and in the first four months in Ayrshire breed. Correlation analysis did not reveal any dependence between changes in the expression level of miRNA and milk fat content, but showed a multidirectional relationship with individual milk fatty acids. Positive associations between the expression levels of miR-106b and miR-30d and protein and casein content were found in the Ayrshire breed. Receiver operating characteristic curve analysis showed that miR-106b and miR-30d expression levels can cause changes in fatty acid and protein composition of milk in Ayrshire cows, whereas miR-106b expression level determines the fatty acid composition in Holsteins. The data obtained in this study showed that miR-106b, miR-191, and miR-30d expression levels in milk samples have peculiarities associated with breed affiliation and the lactation period.

Milk production and nitrogen excretion of grazed dairy cows in response to plantain (Plantago lanceolata) content and lactation season.

The study aimed to quantify milk production and urinary nitrogen (UN) excretion of dairy cows grazing pastures containing varying contents of plantain (Plantago lanceolata) in different seasons, under a typical farm practice. Four pasture treatments: perennial ryegrass (Lolium perenne) - white clover (Trifolium repens) (RGWC), RGWC + low plantain rate, RGWC + medium plantain rate, and RGWC + high plantain rate, were established in four adaptation areas (1 ha each) and 20 experimental plots (800 m2 each), and rotationally grazed by dairy cows over 14 grazing events during two lactation years. In each grazing (8-9 days), 60 or 80 Jersey-Friesian lactation cows were assigned to their pasture treatments, adapted to their pastures over the first six days, then each group of 15 or 20 cows were randomly allocated for grazing in five treatment plots over a two or three-day measurement period. Milk, urine, and faecal samples were collected from individual cows during the measurement period. The pasture treatments did not affect milk production, the yield and composition of milk solids, protein, fat, and lactose. However, cows grazing pastures containing between 17-28% dietary plantain reduced UN concentration by 15-27%, decreased UN excretion by 4-9%, and increased urine volume by 22-40%, compared to grazing the RGWC pasture. The change in UN concentration, and urine volume were associated with plantain proportion in the diet and were greater during late summer and autumn than during early summer. Incorporating 17%-28% dietary plantain with RGWC pastures can reduce the risk of nitrogen losses from pastoral systems, while maintaining the milk production of dairy cows.

Whey protein dynamics in goat mammary secretions during colostrum and early lactation periods.

The protein composition in goat milk undergoes changes throughout the different lactation periods, displaying distinct characteristics that are influenced by the dynamic nature of protein composition and concentration during the transition from colostrum secretion to mature milk. To evaluate the dynamics of whey proteins of Saanen goats during the colostral phase and the first month of lactation, 110 milk samples from 11 healthy mammary halves of seven Saanen goats were selected through a clinical evaluation. Whey was obtained by rennet coagulation of the mammary secretion. The biuret method determined total protein concentration, and their fractions were identified by 12% dodecyl sulfate-polyacrylamide gel electrophoresis. Maximum concentrations of all protein fractions were observed in the first 12 h of lactation, reducing throughout the study. Modification of the protein predominance was also observed. The transition from colostrum secretion to milk occurred 5 or 7 d postpartum.

Determining the influence of raw milk protein composition on the yield of cheese and its nutrient content

Cheese production is a complex process that is influenced by many factors: protein:fat ratio, acidity, and type of rennet. An option for improving the profitability of the cheese industry is the genetic selection of dairy cows to produce milk with good rennet protein coagulation. The object of the study is the technology of cheeses made from milk from cows with different β-casein genotypes (А1А1, А1А2, А2А2). The subject of the study is the physical-chemical parameters of milk from cows with different genotypes for β-casein; yield of cheese from this milk and its quality indicators. Samples of Gouda cheese were produced according to traditional technology. The research established that the quality indicators of milk samples are typical for fresh cow's milk. The content of fat, protein, and dry matter in the milk of cows with the β-casein genotype A2A2 were slightly higher compared to A1A1 and A1A2. The study of the quality indicators of the cheese samples showed that the type of β-casein did not affect the organoleptic properties of the cheese. However, according to the content of the main chemical components, cheeses made from A1A2 milk had a higher content of dry matter and protein (61,6 % and 19,2 % on average, respectively) and a lower fat content (37.2 %). The amino acid profile of cheese from milk of cows with β-casein A1A2 and A2A2 genotypes showed a higher total content of amino acids – 14.89 mg/g and 13.84 mg/g, respectively. Calculations of cheese yield showed that cheese yield from milk of cows with β-casein genotype A1A2 was higher (mean value 13.1 %) than with A1A1 and A2A2. The obtained results are of practical importance, as it is possible to take into account how changes in the β-casein genotype in milk can affect the yield of cheese, and therefore, the profitability of production

Development of Physico-chemical and Technological Parameters for the Production of Dairy Products for Sports Nutrition in Pavlodar Region

Main problem:The article considers the results of research and design of basic formulations of dairy products for sports nutrition in Pavlodar region. The authors analyzed the problems in the field of development of modern food technologies of a specialized orientation. Purpose: To develop physical, chemical and technological parameters for the production of dairy products for sports nutrition in Pavlodar region. Methods: structural-mechanical, physico-chemical, organoleptic. Results and their significance: Reliable research results have been obtained: the fatty acid composition of goat and cow's milk for the production of a new product has been determined, the physico-chemical and structural-mechanical characteristics of goat and cow's milk (raw materials) have been studied. The authors concluded that in the protein composition of goat's milk in the spring and summer period, there is a slight excess of total protein by 0,27 %, whey and casein proteins by 0,07 % and 0,2 %, respectively, non-protein nitrogenous substances by 0,01 % compared with cow's milk. A comparative analysis of the physico-chemical composition of the research objects (goat and cow's milk) was carried out and it was concluded that the mass fraction of solids in the milk of Zaanen goats is 12,8 %, respectively, and significantly exceeds the same indicator of cow's milk – 12,41 %. In the milk of Altai and Alpine goat breeds, the mass fraction of solids ranges from 11,85 % to 11,94 %, which is significantly lower than in cow's milk. The study found that the dry matter content in goat's milk is 8,59 %, which is 0,19 % more than the dry matter in cow's milk. There is a greater amount of protein, respectively, by 0,1 %, while the amount of fat is less than in cow's milk, by almost 1 %.

Analysis of the Differentially Expressed Proteins in Donkey Milk in Different Lactation Stages.

Proteins in donkey milk (DM) have special biological activities. However, the bioactive proteins and their expression regulation in donkey milk are still unclear. Thus, the differentially expressed proteins (DEPs) in DM in different lactation stages were first investigated by data-independent acquisition (DIA) proteomics. A total of 805 proteins were characterized in DM. The composition and content of milk proteins varied with the lactation stage. A total of 445 candidate DEPs related to biological processes and molecular functions were identified between mature milk and colostrum. The 219 down-regulated DEPs were mainly related to complement and coagulation cascades, staphylococcus aureus infection, systemic lupus erythematosus, prion diseases, AGE-RAGE signaling pathways in diabetic complications, and pertussis. The 226 up-regulated DEPs were mainly involved in metabolic pathways related to nutrient (fat, carbohydrate, nucleic acid, and vitamin) metabolism. Some other DEPs in milk from the lactation period of 30 to 180 days also had activities such as promoting cell proliferation, promoting antioxidant, immunoregulation, anti-inflammatory, and antibacterial effects, and enhancing skin moisture. DM can be used as a nutritional substitute for infants, as well as for cosmetic and medical purposes. Our results provide important insights for understanding the bioactive protein differences in DM in different lactation stages.

The Protein Composition of Bovine Milk from Once-a-Day and Twice-a-Day Milking Production Systems in New Zealand

An increasing number of dairy farmers in New Zealand (NZ) have adopted a once-a-day (OAD) milking production system, and little is known about the impact of this production system on milk protein composition. The objective of this study was to evaluate the effect of OAD milking on the protein composition in milk from individual cows. Milk was sampled in early, mid-, and late lactation from cows kept at Massey University farms Dairy No. 1 (OAD milking) and Dairy No. 4 (TAD milking) in Palmerston North, NZ. The yields of total milk and milk solids, the proximate composition, and the protein composition were determined. Results showed that OAD milking yielded less milk and milk solids than TAD milking. However, no significant differences in protein, fat, and lactose contents were found. While the proportions of total casein (CN), total whey proteins, αs1-CN, β-CN, and β-lactoglobulin were not affected by the milking frequency, milk from a OAD milking system contained higher proportions of αs2-CN and κ-CN and lower proportions of α-lactalbumin. These proteins also changed differently throughout the milking season in a OAD milking system than in a TAD milking system. These changes in the protein composition of the milk observed in a OAD milking system could have implications for its processing properties and product quality.

Functional foods are essential components of nutrition

The most common category of functional nutrition is fermented milk products, which normalize the intestinal microflora and increase the immune status of the human body. Fermented milk products are characterized by high biological and nutritional values. This means a high degree of balance in the amino acid composition of milk proteins, compared to the so-called ideal food protein, the amino acid composition of which meets the needs of the human body. In addition, the proteins of fermented milk products are well digested by proteolytic enzymes of the gastrointestinal tract. The main casein proteins are capable of being broken down equally well by proteolytic enzymes in their native and denatured states. The macroorganism and intestinal microflora are a relatively stable and balanced ecological system, the balance of which, on the one hand, is determined by the physiological and immunological characteristics of the macroorganism, on the other, by the species and quantitative composition of microbial associations and the diversity of their biological activity. In a normal physiological state, the relationship between the macroorganism and the microflora is symbiotic in nature, and the latter has a significant impact on the general immunity and natural resistance of the host to infections, takes an active part in the processes of digestion and the synthesis of various biologically active substances. In turn, the macroorganism regulates the composition of the intestinal microflora due to factors such as the acidity of gastric juice and the content of bile salts. Fermented dairy products are the main suppliers of probiotic microorganisms that contribute to the maintenance and restoration of human microbial ecology. Probiotic cultures that provide beneficial effects on the consumer’s body and normalize the composition and functions of the microflora of the gastrointestinal tract include such types of lacto- and bifidobacteria as Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium spp. (B. adolescentis, B. animalis ssp. lactis, B. bifidum, B. longum, B. breve).

Effects of CSN1S1 and CSN3 casein gene polymorphisms on milk protein composition, milk production, and curd yield of water buffaloes

The influence of polymorphisms in CSN1S1 and CSN3 genes on composition and individual casein (CN) proteins of milk, milk production, and curd yield of Murrah buffalo cows was evaluated. Higher amounts of the individual casein proteins αS1-CNB and κ-CNX2 in milk were observed in animals with the CT and CC alleles, respectively. Milk from animals with the CT allele showed higher levels of fat, total dry extract (TDE), and milk urea nitrogen (MUN) than those from animals with the CC allele. Murrah buffalo cows with genotypic combinations of AACC and AGCT of CSN1S1 and CSN3 were associated with higher milk and curd yields. In addition, the CSN3 gene alleles (CC and CT) are responsible for the higher curd yield in cheese making, which is associated with a higher content of casein κ-CNX1, κ-CNX2, αS1-CNB, and fat.

PSI-A-1 Effects of Agolin-Pig on Milk Composition Throughout Lactation

Abstract Essential oils are increasingly being used in the swine industry as an alternative to antibiotics. New areas of research indicate that essential oils may alter milk composition and production in lactating sows with the potential of increasing resistance of piglets to harmful bacteria. The purpose of this preliminary study was to determine the effects of Agolin-Pig, a product containing micro-encapsulated essential oils, on milk composition and production. The treatment group (n = 13) consisted of sows fed 200 ppm of Agolin-Pig mixed in an in-house premix combined with a standard lactation diet (NRC, 2012). The control group (n = 13) consisted of sows fed the same diet without added essential oils. All sows were started on their corresponding diets 14 days before their calculated farrowing date. Sows were induced on day 114 of gestation if they had not already farrowed. Colostrum was collected within 2 hours of the onset of farrowing from all teats and mixed to form a 50 to 100 mL homogenate, representative sample. On days 3 and 14 of lactation, sows were administered 0.5 mL of oxytocin via their ear vein to induce milk ejection. Three teats were selected along the midline of the sow and milked completely into 3 separate, corresponding 50 mL conical tubes. All milk samples were stored at -20°C until analysis. Protein composition of the three teats was averaged by sow before statistical analysis. Weigh-suckle-weigh (WSW), an indirect measure of milk production, was performed on d 10 to 12 of lactation by removing piglets from the sow for 45 minutes before recording a litter weight. The piglets were then returned to the sow to nurse for 30 minutes and weighed again. Colostrum and milk samples were analyzed for protein composition via a Bradford assay using a bovine serum albumin (BSA) standard. The PROC Mixed procedure of SAS v9.4 (Cary, North Carolina) was used to evaluate the effects of Agolin-Pig on the protein composition of milk at day 0, day 3, and day 14 of lactation along with WSW data. Treatment and parity (P1 vs P ≥ 2) were main effects with day of collection as a repeated measure and the random effect of sow. There was a significant decrease for both groups in protein composition from day 0 to 3 (P = 0.0001) and day 0 to 14 (P < 0.0001) with no significant change between day 3 to 14, which is expected as colostrum transitions into whole milk. There were no significant differences between treatment groups in protein milk composition throughout lactation. WSW data showed no significant differences between treatments in milk production. While no significant differences were observed in milk composition and production, future analysis will show the effects of Agolin-Pig on milk fat and immunoglobulin composition during lactation.

Сезонные изменения биологической ценности белков молока ослиц киргизской породы

Due to its protein component, donkey’s milk is a multifunctional product with a wide range of beneficial physiological properties. It is known for its antioxidant, anti-inflammatory, rejuvenating, antimicrobial, and antitumor effects. However, the milk of Kyrgyz donkeys has not received proper scientific attention in this respect. This study analyzed the seasonal amino acid profile and biological value of milk obtained from Kyrgyz donkeys.
 The donkeys belonged to the Kyrgyz breed and inhabited the highlands of the Chui Region, Republic of Kyrgyzstan. The sampling took place in April, July, and September. The amino acid composition of milk proteins was determined by capillary electrophoresis. The biological value of proteins was assessed by amino acid score, index of essential amino acids (Auxerre index), utility ratio of essential amino acids, and utility ratio of amino acid composition.
 The analysis revealed 18 amino acids, including eight essential ones. The total content of amino acids in the spring samples was 1840.07 mg/100 g. In the summer samples, this value peaked at 2037 mg/100 g; in autumn, it dropped to 1264.35 mg/100 g. The changes could be explained by the seasonal differences in the diet. The ratio of essential to non-essential amino acids approached 1:1. The milk also proved to contain arginine, which is an essential amino acid for a juvenile organism. In the spring samples, its content was 2.5 times as big as in the autumn ones. Leucine and isoleucine were responsible for 1/3 of the essential amino acids (322.60 ± 19.35 mg/100 g). The summer samples demonstrated the maximal content of some other essential amino acids, except for valine and tryptophan, which appeared to be the limiting essential amino acids for donkey’s milk in the autumn period. Total essential amino acids in the spring, summer, and autumn samples amounted to 54.24, 59.26, and 34.77 g/100 g, respectively, which exceeded the value for the reference protein (27.46 g/100 g).
 Kyrgyz donkey’s milk proteins were of high biological value, regardless of the season, which means that donkey’s milk can become part of new functional products.

Peptidome comparison on the immune regulation effects of different casein fractions in a cyclophosphamide mouse model

The protein composition of human milk plays a crucial role in infant formula milk powder formulation. Notably, significant differences exist between bovine casein and human milk casein. Previous studies have shown that casein hydrolysates could enhance immune function; however, gastrointestinal dyspepsia in infants affects the type and function of peptides. Therefore, the present study used peptidomics to sequence and analyze hydrolyzed peptides from different casein fractions. Additionally, animal experiments were conducted to assess the functionality of these casein fractions and elucidate their differences. The results revealed variations in peptide composition among the different casein fractions of formula milk powder. Interestingly, milk powder formulated with both β- and κ-casein (BK) exhibited significant enrichment of peptides related to the immune system. Moreover, the BK group significantly alleviated immune organ damage in cyclophosphamide-treated mice and regulated serum levels of pro-inflammatory and anti-inflammatory factors. Furthermore, feeding different casein fractions influenced the intestinal microflora of cyclophosphamide-treated mice, with the BK group mitigating the changes caused by cyclophosphamide. In conclusion, the findings suggest that BK formula in milk powder has the potential to positively enhance immunity. This study provides a robust theoretical basis for human-emulsified formula milk powder development.

Developing flexible models for genetic evaluations in smallholder crossbred dairy farms

The productivity of smallholder dairy farms is very low in developing countries. Important genetic gains could be realized using genomic selection, but genetic evaluations need to be tailored for lack of pedigree information and very small farm sizes. To accommodate this situation, we propose a flexible Bayesian model for the genetic evaluation of milk yield, which allows us to simultaneously account for nongenetic random effects for farms and varying SNP variance (BayesR model). First, we used simulations based on real genotype data from Indian crossbred dairy cattle to demonstrate that the proposed model can separate the true genetic and nongenetic parameters even for small farm sizes (2 cows on average) although with high standard errors in scenarios with low heritability. The accuracy of genomic genetic evaluation increased until farm size was approximately 5. We then applied the model to real data from 4,655 crossbred cows with 106,109 monthly test day milk records and 689,750 autosomal SNPs. We estimated a heritability of 0.16 (0.04) for milk yield and using cross-validation, a genomic estimated breeding value (GEBV) accuracy of 0.45 and bias (regression of phenotype on GEBV) of 1.04 (0.26). Estimated genetic parameters were very similar using BayesR, BayesC, and genomic BLUP approaches. Candidate genes near the top variants, IMMP2L and ARHGEF2, have been previously associated with milk protein composition, mastitis resistance, and milk cholesterol content. The estimated heritability and GEBV accuracy for milk yield are much lower than those from intensive or pasture-based systems in many countries. Further increases in the number of phenotyped and genotyped animals in farms with at least 2 cows (preferably 3-5, to allow for dropout of cows) are needed to improve the estimation of genetic effects in these smallholder dairy farms.