Effect of milk protein content in Toddler formula on later BMI and obesity risk: protocol of the multicentre randomised controlled Toddler Milk Intervention (ToMI) trial

IntroductionReduction of milk protein content in infant formula provided during the first year of life has been shown to reduce early weight gain and obesity later in life. While rapid weight gain during the first 2 years of life is one of the strongest early predictors of obesity, the role of animal protein intake beyond the first year of life is unclear. The aim of this study is to examine the role of milk protein during the second year of life in healthy children on weight gain and obesity risk in preschool age.Methods and analysisThis randomised, double-blinded study enrolled 1618 children aged 11.5–13.5 months in Spain and Germany into two groups receiving isocaloric toddler milk with differing protein content during the second year of life. The experimental formula contains 1.5 g/100 kcal and the control formula 6.15 g/100 kcal protein and otherwise equal formula composition, except for modified fat content to achieve equal energy density. The primary endpoint is body mass index (BMI)-for-age z-score at the age of 24 months adjusted for BMI at 12 months of age. The children are followed until 6 years of age.Ethics and disseminationEthics approval was obtained from the ethical committees of the LMU University Hospital Munich, Germany (Nr. 555-15) and at Institut d’Investigació Sanitaria Pere Virgili, Reus, Spain (Ref. CEIm IISPV 013/2016). We aim at publishing results in peer-reviewed journals and sharing of results with study participants.Trial registration numberNCT02907502.

Metabolic and production parameters of dairy cows with different dry period lengths and parities

To assess the effects of dry period (DP) length on metabolic, reproductive, and productive parameters, second- (SP) and third- (TP) parity cows were assigned to a traditional (9 weeks, T) or short (5 weeks, S) DP, obtaining four subgroups: second-parity cows with traditional (SPT = 8) and short (SPS = 8) DP, third-parity cows with traditional (TPT = 8) and short (TPS = 10) DP. Plasma insulin-like growth factor-I (IGF-I) and non-esterified fatty acid (NEFA) levels were assessed from 5 weeks before to 14 weeks after parturition. IGF-I concentrations were affected by parity (P < 0.05) and by the interaction of time and DP length (P < 0.01). NEFA levels were affected only by time (P < 0.01). S DP cows showed a shorter interval between calving and ovarian cyclicity resumption (P < 0.01) and a higher milk yield (P < 0.01) and fat and protein corrected milk (P < 0.01) compared with T DP cows. Decreased milk protein content was found in the SPS group compared to the SPT (P < 0.05) and the TPS (P < 0.05) group. In conclusion, a short DP length does not affect reproductive performances, except for hastening the resumption of ovarian cyclicity. A short DP appears to increase milk production and is associated with higher IGF-I levels both in the prepartum and the postpartum period.

156 Genome-wide DNA Methylation Profile of Mammary Gland Tissues from Holstein Cattle Producing Various Milk Protein Yields

Milk protein content is attracting considerable attention due to increasing demand for high-quality products. Epigenetic marks including DNA methylation have demonstrated considerable potential to contribute to the achievement of increased gain in bovine milk traits. To investigate potential roles of DNA methylation in regulating milk protein productivity, whole genome bisulfite sequencing was used to profile the global DNA methylation of mammary gland (MG) tissues from Canadian Holstein cows producing milk with high protein (HMP) (&gt;4.0%, n = 5) or low protein (LMP) (&lt; 3.0%, n = 7) contents. Bioinformatics processing using standard tools and construction of the methylation landscape of MG was based on methylation sites with ≥10× coverage. A total of 2420 differentially methylated CpG (DMC) sites, including 1842 with higher and 578 with lower methylation levels (FDR&lt; 0.1) were identified when HMP group was compared with LMP group. DMCs were most abundant on chromosomes 2 (n=347) and 27 (N=535), respectively. The most DMCs were annotated to mRNAs, followed by lncRNAs, pseudogenes and rRNAs. Eight genes harbored five or more DMCs each, including LOC112443250 (5S ribosomal RNA) and LOC112443149 (liprin-alpha-1-like, LIP1) (harbored 20 hypermethylated and 1 hypomethylated sites, each), followed by miR-2287-1 (12 hypomethylated sites), etc. LIP1, a liprin family member interacts with LAR family members to play important roles in MG development. MiR-2287-1 and other family members are frequently identified in MG tissues and milk and are associated with many livestock diseases. Interestingly, among the DMCs that overlap with QTLs related to milk production were clusters on chromosomes 27 (N=534) and 14 (N=91) that associated with milk protein yield. In conclusion, DNA methylation showed potential involvement in the genetic variation underlying milk protein content and MG biological processes. More analysis with a higher sample size is however necessary to adequately quantify the involvement of DNA methylation in the regulation of milk protein content and mammary gland development.

A Study on Microbial and Macronutrient Composition of Breast Milk Varies with Lactation Duration

Complementary feeding and continuation of breast feeding is directed and advised by the national and international child health agencies. Breast milk, a complex biological fluid, shows changes in its cellular, microbial and nutrient composition as lactation progresses. In a cross-sectional study, hospital-based pilot project showed the composition of microbial and macronutrients and compared their differences before and after first six months of lactation. Staphylococcus aureus was the predominant bacterium found in breast milk, and 45% (15/33) of samples within first six months and only 13% (3/22) from those more than six months of lactation showed any bacterial growth (p=0.013). The protein content was less in breast milk samples after six months compared to those within six months of lactation (mean difference, 95% CI: 0.33 (0.10, 0.55) gm/dL, p=0.005). After controlling the lactation period, bacterial culture positivity in breast milk was associated directly with the breast milk protein content. Our pilot study observations indicate the need to study microbial and nutrient changes in breast milk as lactation advances, in a longitudinal study with larger sample size, and investigate its associations with maternal factors, infant growth, establishment of infant gut microbiota and possible role in environmental enteric dysfunction.

Dairy productivity of zaanen type goats hybrids from crossing with the nubian breed bucks

Изучена молочная продуктивность потомства I, II и III поколений при скрещивании молочных коз в типе зааненской породы с козлами нубийской породы. Установлено, что самый высокий удой за лактацию (576,5±11,62) был у чистопородных зааненских коз (n=72) — на 10,8—25,3% (P≦0,05) больше, чем у помесных животных за счет более длительной лактации (на 13,0%). Среднесуточный удой за лактацию был на 2,1% выше у помесей I поколения (n=26), чем у зааненских, на 4,9% — чем у помесей II (n=24) и на 13,5% — чем у помесей III поколений (n=21) (P≦0,05). Козоматки III поколения по содержанию жира превосходили сверстниц на 0,14—0,50 абс. процента, а белка — на 0,18—0,37 абс. процента. Среднесуточное количество молочного жира было выше у помесей I поколения на 0,9—7,3%, молочного белка — на 1,5—5,1%. За счет более продолжительного периода лактации козоматки зааненской породы превосходили своих помесных сверстниц по количеству молочного жира на 5,3—11,8% (1,2—2,5 кг) и по количеству молочного белка — на 7,7—11,3% (1,2—1,7 кг). Таким образом, поглотительное скрещивание является эффективным приемом для получения чистопородных животных нубийской породы. И может быть использовано в качестве селекционного приема в товарных хозяйствах для повышения качественных показателей молока коз в типе зааненской породы. Milk productivity of the offspring of generations I, II, and III during milk goat breeding in the type of the Saanen breed with goats of the Nubian breed was studied. It was found that the highest milk yield per lactation (576.5±11.62) was demonstrated by purebred Saanen goats (n=72) — by 10.8—25.3% (P≦0.05) more than in crossbred animals due to prolonged lactation (by 13.0%). Average daily milk yield per lactation was 2.1% higher in crossbred animals of generation I (n=26) compared to the Saanen breed, 4.9% higher than in crossbred animals of generation II (n=24), and 13.5% higher than in crossbred animals of generation III (n-21) (P≦0.05). By fat content the breeding goats of generation III are superior to their age-mates by 0.14—0.50 absolute percent, and by protein — by 0.18—0.37 absolute percent. Average daily milk fat content was 0.9—7.3% higher in crossbred animals of generation I; average daily milk protein content was 1.5—5.1% higher. Due to prolonged lactation breeding goats of the Saanen breed were superior to their crossbred age-mates in milk fat quantity by 5.3—11.8% (1.2—2.5 kg), and in milk protein quantity — by 7.7—11.3% (1.2—1.7 kg). Accordingly, accumulation cross breeding is an effective method of obtaining purebred animals of the Nubian breed. It can be used as a selection technique in commercial farming to increase qualitative characteristics of goat milk in the type of the Saanen breed.

Production and marginal analysis of lactating cows subjected to dietary cation-anion balances

The objective of this study was to evaluate productive, nutritional, and economic traits in lactating cows on pasture fed diets with different cation-anion balances (DCAB). Ten lactating ¾ Holstein × ¼ Dairy Gyr cows in the middle third of lactation, at an average age of 70 ± 4.6 months and an average body weight of 400 ± 55.2 kg, were distributed into five treatments in a 5 × 5 Latin square experimental design with two simultaneous squares. Treatments consisted of diets with DCAB of +237, +258, +294, +347, or +419 mEq dry matter (DM). No effects of intake were observed. There was no significant effect of DCAB on milk yield. The milk protein content was not influenced by the DCAB. Body condition score was not significantly affected by the DCAB. The apparent digestibilities of dry matter and nutrients (crude protein, neutral detergent fiber, ether extract, non-fibrous carbohydrates, and total digestible nutrients) were not affected by the DCAB. Marginal rate of return did not show significant differences. Under good conditions of pasture, forage availability, and quality associated with the lactation phases of the cows, all diets were efficient in milk production, dry matter intake, and digestibility. However, in economic terms, the most attractive DCAB was +237 mEq kg-1 DM.

43 Cow Performance and Lameness Are Affected by Housing in Drylots vs Pasture During the Summer

The objective was to compare the performance of cows housed in drylots or on pasture. Spring-calving, Simmental × Angus cow-calf pairs (n = 108; 77 ± 18 days postpartum) were stratified by age, body weight (BW), body condition score (BCS), calving date, and calf sex. Cows were allotted into six groups which were randomly assigned to drylot or pasture. Drylot cows were limit-fed a ration consisting of corn silage, dried distillers grain, corn stalks, cracked corn, and a corn-based supplement to meet protein and energy requirements. Cows on pasture were rotationally grazed with access to free-choice mineral. Cows were artificially inseminated on day 0. Cow BW, BCS, hair coat scores, locomotion scores, and lameness treatments were evaluated throughout the 110-day experiment. Milk production and composition were evaluated on day 56. Data were analyzed using the MIXED and GLIMMIX (binary data) procedures of SAS. Artificial insemination and overall pregnancy rates did not differ (P ≥ 0.79) between groups. Drylot cows were 22 and 51 kg heavier (P ≤ 0.02) than pasture cows on days 83 and 110, respectively. Drylot cow BCS was greater (P = 0.03) on day 110. Hair coat scores were more desirable (P = 0.03) in drylot cows than pasture cows on day 110. Drylot cows had greater (P = 0.04) milk production than pasture cows. Pasture cows had greater (P ≤ 0.03) milk protein content and milk urea nitrogen. Although locomotion scores did not differ (P ≥ 0.45) on days 0 and 34, they were less desirable (P = 0.02) for the drylot cows on day 110. A greater (P = 0.02) percentage of drylot cows (33%) were treated for lameness than pasture cows (7%). Housing cows in drylots increased BW, BCS, and milk production, but resulted in poorer locomotion scores and increased lameness treatments.

Variation in PLIN2 and its association with milk traits and milk fat composition in dairy cows

The current study investigated associations between variation in the bovine perilipin-2 gene (PLIN2) and milk traits (milk fat content, milk protein content, milk yield and milk fatty acid (FA) component levels) in 409 New Zealand pasture-grazed Holstein-Friesian × Jersey-cross (HF × J-cross or Kiwicross™) cows. Five nucleotide sequence variants were found in three regions of the gene, including c.17C>T in exon 2, c.53A>G in exon 3, c.595+23G>A and c.595+104_595+108del in intron 5, and c.*302T>C in the 3′-untranslated region. The c.*302T>C substitution produces two nucleotide sequence variants (A5 and B5), and this variation was associated with variation in milk protein content and milkfat composition for C10:0, C11:0, C12:0, C13:0 and C16:0 FA and medium-chain fatty acid (MCFA) and long-chain fatty acid (LCFA) groups. After correcting for the effect of variation in the diacylglycerol acyl-CoA acyltransferase 1 gene (DGAT1) that results in the amino acid substitution p.K232A, variation in the FA binding protein 4 gene (FABP4) and variation in the stearoyl-CoA desaturase (Δ-9-desaturase) gene (SCD) that results in the amino acids substitution p.A293V, significant differences between A5A5 and B5B5 cows were found for C10:0, C11:0, C12:0, C13:0, C16:0, and the MCFA, LCFA, total saturated FA and C10:1 index groups. This suggests that nucleotide sequence variation in PLIN2 may be affecting milk FA component levels.

Impacts of Heat Stress-Induced Oxidative Stress on the Milk Protein Biosynthesis of Dairy Cows

Heat stress (HS) is one of the most important factors posing harm to the economic wellbeing of dairy industries, as it reduces milk yield as well as milk protein content. Recent studies suggest that HS participates in the induction of tissue oxidative stress (OS), as elevated levels of reactive oxygen species (ROS) and mitochondrial dysfunction were observed in dairy cows exposed to hot conditions. The OS induced by HS likely contributes to the reduction in milk protein content, since insulin resistance and apoptosis are promoted by OS and are negatively associated with the synthesis of milk proteins. The apoptosis in the mammary gland directly decreases the amount of mammary epithelial cells, while the insulin resistance affects the regulation of insulin on mTOR pathways. To alleviate OS damages, strategies including antioxidants supplementation have been adopted, but caution needs to be applied as an inappropriate supplement with antioxidants can be harmful. Furthermore, the complete mechanisms by which HS induces OS and OS influences milk protein synthesis are still unclear and further investigation is needed.