The purpose of this investigation was to modify the procedure of Bills, Khatri and Day for use in the development of a suitable method for determining the quantitative distribution of the free fatty acids (FFA) in normal, heated, and rancid milk and milk fractions The method consists of extracting the FFA from lyophilized milk, separating the FFA from neutral fat, converting the FFA to methyl esters, and analyzing the methyl esters by gas-liquid chromatography (GLC). The salts of FFA present in lyophilized milk or milk fractions were released by lowering the pH of the sample with H₂SO₄, and subsequently extracted with ethyl ether. The extracted FFA were simultaneously isolated from the extract and methylated by using the one-step procedure of Bills, Khatri and Day. A specially designed concentration flask was employed with a reflux system to concentrate the methyl esters. The esters were then separated by GLC. Quantitative calculations were made from the GLC peak areas using internal standards. The major esterified fatty acids of milk are n-saturated, evennumbered 4:0-18:0 and unsaturated 18:1 and 18:2 acids. The distribution of major FFA in whole milks was found to be essentially the same as that of the esterified fatty acids of milk fat. Heat treatments of milk, whether pasturization or extended holding at 100°C, effect a progressive reduction in total FFA. Decreases in long chain fatty acids are also characteristic of extended heating. Milks determined to be rancid by acid degree value and organoleptic analysis showed high levels of FFA, 1.5-3.6% of the fat content of the sample. The increases in 6:0-12:0 resulting from lipase hydrolysis approximate the amounts shown by Al-Shabibi and co-authors to produce rancid flavor when added to good quality milk. Milk triglycerides, fat globule membrane, skim milk, and buttermilk show characteristic FFA patterns which appear to be related to the solubility properties of the individual acids. Seventy-one percent of the total FFA in a given portion of 40% cream was found in the triglyceride fraction, 26% in the crudie fat globule membrane preparation and 3% in the skim milk fraction. The total concentrations of FFA were found to be: 1% of the fat in whole milk or 0.04% of the fluid milk weight; 0.16% of the total weight of 40% cream; 0.28% of centrifuged triglycerides; 1.7% of the fat globule membrane; and 0.008% of the fluid weight of skim milk. / Graduation date: 1965

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Typescript (photocopy). / Digitized by Kansas Correctional Industries

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A total of 596 milk samples with varying fat (3.0 to 4.0%) and protein (3.0 to 4.0%) contents were used to make laboratory-scale cheese and to determine coagulating properties. Higher levels of fat and protein in milk were associated with higher cheese yield. Milk protein has greater effect on cheese yield than milk fat. Adjusted yield increased by 1.91 and 1.29% for every percentage increase in the protein and fat of milk, respectively. Higher levels of fat in milk produced a cheese containing higher fat content and lower protein content. Similarly, higher levels of protein in milk produced higher protein content and lower fat content of cheese. Higher protein to fat ratio (or casein to fat ratio) in milk was associated with better efficiency of fat retention in the cheese. Casein retention in the cheese was not affected by the levels of fat and protein, or protein to fat ratio in milk. Milk adjusted for fat and protein resulted in delayed coagulation and a significant decrease in the curd firmness when compared with unadjusted bulk tank milk having the same levels of the two components.

In conditions where supplementation of poor quality diets is a major challenge, forage legumes such as Sericea lespedeza can be a good alternative supplement for protein at lower cost than most commercial concentrates. From studies done on Sericea lespedeza it is found plausible and valuable to supplement urea with Sericea lespedeza to strategically combat the deleterious effect of condensed tannins in the Sericea lespedeza and provide nitrogen in the rumen. This study was aimed to evaluate the effect of replacing sunflower oilcake with urea (a rumen degradable protein RDP source) or Sericea lespedeza (rumen undegradable protein RUP source) mixed with urea as nitrogen/protein sources on nutrient utilization, milk yield and milk composition of Saanen dairy goats. A digestibility and lactation study were conducted at the University of Pretoria Research Farm and chemical analysis performed at the University Nutrilab. A 30 days digestibility study was conducted on male Saanen goats after the lactation study, with 23 days adaptation and 7 days data collection period. Nine male goats were randomised and allocated to the three treatments in metabolism cages. In the lactation study 36 dairy goats were blocked according to milk collected on first month of lactation into high, medium and low milk yielders, then allocated to the three treatments of total mixed rations containing sunflower oilcake (T1) at 7% main protein source, T2 (urea at 1%) and T3- Sericea lespedeza at 12.5% mixed with urea according to a complete randomised block design (CRBD). Milk samples were collected from individual goats monthly at two consecutive milking’s. The samples were analysed for milk fat, protein, lactose, somatic cell count and milk urea nitrogen using a Milko-Scan analyser (at Irene Lacto lab). In the digestibility study, dry matter intake was significantly higher for goats fed on Sericea lespedeza with urea (T3) diet than goats fed on T1 and T2 diet. Goats on T3 diet had also significantly higher organic matter and crude protein intake than those goats fed on the other two TMR diets. The results also shows that the mean daily milk yields for the goats in the T1, T2 and T3 were 2.56, 2.46 and 2.52 kg per day respectively. T2 group had higher milk fat % (3.61) and higher milk urea nitrogen (MUN - 25.70 mg N/dl) than the other two treatments. T1 had significantly higher milk protein %. There was a great difference in milk composition of the afternoon milk as compared to the morning milk. The three TMRs had no significant difference in the nitrogen utilization and nitrogen excretion. It is then concluded that Sericea lespedeza mixed with urea can be used as subsititutes for sunflower oilcake in the diets of dairy goats since no negetive effect was found. However further investigations are needed. / Dissertation (MSc Agric)--University of Pretoria, 2017. / DAAD-NRF / International Foundation for Science (IFS) / Animal and Wildlife Sciences / MSc (Agric) / Unrestricted

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Distribution and bioavailability of ⁴⁷calcium in milk labeled by extrinsic and intrinsic methods was investigated. Milk from Sprague Dawley rats was labeled by both methods, and milk from a cow was labeled by the extrinsic method. Retention of ⁴⁷Ca from milks administered to young male Sprague Dawley rats was determined through whole body counting for 6 days after administration of milk. Percent of ⁴⁷Ca dose retained was 72% for extrinsically labeled cow milk, 62% for extrinsically labeled rat milk, and 55% for intrinsically labeled rat milk. Samples were fractionated by ultracentrifugation and by gel exclusion chromatography. ⁴⁷Calcium distributions in rat milk labeled intrinsically or extrinsically were similar. The majority of ⁴⁷Ca was found in a particulate, > 30,000 molecular weight fraction (about 60% for cow milk, about 90% rat milks). The amount of milk calcium retained by rats appeared to be related to the amount of noncasein micelle-associated calcium. When administered by intraperitoneal injection into rats, ⁴⁵Ca specific activity of milk peaked in 60 to 90 minutes. Specific activity was highest in cytosol, and lower in Golgi apparatus and rough endoplasmic reticulum. Specific activities in subcellular fractions changed in parallel with specific activities of milk. Rapid turnover of Ca was observed in endoplasmic reticulum and Golgi apparatus; this was expected since secretory proteins and associated Ca are transported through these organelles for secretion. In vitro ⁴⁵Ca accumulation was compared in Golgi apparatus and endoplasmic reticulum from liver and mammary gland of lactating Dunkin Hartley guinea pigs. In the presence of ATP, highest accumulation per unit total fraction protein was found in Golgi apparatus (mammary gland 28% of available ⁴⁵Ca, liver 11%) while 8% was accumulated by endoplasmic reticulum fractions. Calcium accumulation was not the result of binding, as preincubation of vesicles with calcium ionophore resulted in less than 10% of the accumulation found without ionophore. The ATPase inhibitor sodium orthovanadate, and the ATP analog AMP-PNP, reduced ⁴⁵Ca accumulation in all fractions. Protonophore caused a small reduction in ⁴⁵Ca accumulation in all cases. Citrate accumulation by fractions was not observed under conditions used for ⁴⁵Ca accumulation. / Ph. D.

The quality of early milk produced by dams is affected by various factors (i.e. breed, age, parity, environment, nutrition, management). The impact of these factors on the quality of milk then have subsequent effects on calf health and development. Producers are responsible for following guidelines in order to ensure that they feed calves optimal quality milk in order to produce a healthy animal. They can also regulate factors such as environment and nutrition of the dam in order to produce better quality early milk. However, even after maximizing these factors there is still high mortality rate among pre-weaned calves, therefore, other factors such as mode of birth and genetics need to be studied to determine impacts on early milk quality and make further improvements to calf health and decrease mortality. Two experiments were conducted in order to study the effects of maternal and genetic factors on early milk production and to determine relationships that exist with calf health. The objective of the first study was to determine the effects that the mode of delivery had on early milk composition, and on the rumen microbiome of calves. We hypothesized that mode of birth would impact early milk composition, and, in turn, influence the microbial phyla in the calf gut. The second study had three objectives: 1) establish phenotypic relationships between colostrum composition traits, milk production traits, and calf health, 2) determine impact of breed and season on colostrum production and 3) ) elucidate the genetic parameters (i.e. heritability, genotypic, and phenotypic correlations) among colostrum production and milk production We hypothesized that colostrum composition and production differ among breeds and by season and that individual components influence calf health. Additionally, we hypothesized that colostrum quality traits (i.e. Brix score and volume) are heritable. For the first study Charolaise (CHAR; n = 23) and Angus (ANG; n = 15) dams were divided into two experimental groups; dams underwent vaginal (VD; n= 25) or cesarean (CD; n= 13) deliveries. Early milk samples were collected and quantified for protein, lactose, somatic cell count, and fatty acid concentrations. After parturition calves were separated based on dams experimental group. Rumen fluid was collected from calves on d 1, 3, and 28 post-partum. Extracted DNA from fluid were used for metagenomic sequencing (ANG calves, n=11; CHAR calves, n=13). Samples were run on the HiSeq 2500 platform as paired end reads according to Ilumina's standard sequencing protocol. A regression analysis was done in SAS using PROC GLM and regressing mode of birth on milk components for d 1,3, and 28. After, milk components found to be significantly impacted by mode of birth were regressed against microbial counts. Results showed that VD dams were more likely to have increased (P  0.05) protein, solids non-fat, and lactose on d 1 and 3, but decreased (P < 0.05) urea concentrations. Similarly, short, medium, and long-chain fatty acids were increased (P  0.05) in VD d 3 milk. Changes in true protein elicited a decrease (P  0.05) in rumen fluid Actinobacteria and Proteobacteria; whereas, both solids non-fat and lactose were associated with an increased (P  0.05) response in d 1 transition milk. No significant results for d 28 of sampling were observed. Based on our results we suggest that mode of birth influences protein concentrations in early milk. However, only a slight impact on the overall dynamics of the calf rumen was observed with the microbiome remaining relatively stable on the phyla level in response to changes in protein concentration. The second study looked into relationships between colostrum composition traits, management practices, and calf health, as well as determined heritability and genetic correlations for colostrum quality traits. Values for test-day milk, protein, fat, and somatic cell count (SCS) for Holstein (HO, n= 250) and Jersey (JE, n=289) cows were obtained from the Animal Genomic and Improvement laboratory server at the USDA. Brix score, colostrum weight, dam age, parity, and 3-month season of calving were also recorded. After, colostrum samples from JE cows were sent to DHIA where compositional measurements were obtained (i.e. true protein, fat, lactose, SCS, solid non-fats). Lactoferrin concentration for JE colostrum samples was also determined via ELISA. Calf blood samples were collected within 72 h post-partum and total serum protein (TSP) quantified to determine success of passive immunity transfer. Additionally, farm staff were instructed to record colostrum source for 1st feeding (i.e. dam, mix, other), freshness for 1st feeding (frozen vs fresh), Brix score of colostrum fed, volume of colostrum fed, and birth weight. A PROC Mixed with LSMEANS was performed in SAS to determine relationships between colostrum components, test day components, and quality traits for season, breed, and the interaction between season and breed. Also, PROC Mixed with LSMEANS was used to determine relationships of calf health with environment, management, and colostrum components. Additionally, a Pearson correlation was used to determine relationships between colostrum components and quality traits. Results for Holstein and Jersey showed that both colostrum Brix and volume (P < 0.001) differed by breed. Colostrum volume (P < 0.001), lactose (P < 0.001), and lactoferrin (P = 0.002) varied significantly by season. Additionally, test day milk (P = 0.046), fat (P = 0.012), and protein (P = 0.003) varied significantly by season. Moreover, a significant season and breed interaction (P = 0.028) was observed solely for colostrum volume. Calf health models indicated that TSP, colostrum total protein and solid non-fats impacted incidence of respiratory illness, but no factor significantly impacted incidence of scours. Results for Pearson correlation indicated strong correlations between true protein and solid non-fats and Brix (r = 0.99; 0.86). Lactoferrin also had moderate negative correlations with volume and lactose (r = -0.35; -0.33). Heritability and repeatability's were calculated using BLUPF90 family of programs. A single-trait repeatability animal model was used and included a 1-vector phenotype (Brix or Colostrum weight), fixed effects (i.e. calving year, parity, 3-month season of calving, and age at calving), additive genetic variance, random permanent environment effects, and random residual effects. A series of bivariate models were used to calculate genetic correlations of Brix score and colostrum weight with test-day compositional traits. Heritability estimates results for Holstein cow Brix and colostrum weight, were 0.25 and 0.15. Jersey cow heritability estimates were 0.36 and 0.47 respectively. We also observed some significant genetic correlations with Holstein Brix score and test-day milk (-0.23), fat (0.54), and SCS (0.29) having moderate correlations. Holstein colostrum weight had a strong correlation with test-day milk (0.96). Jerseys had strong genetic correlation of Brix score with colostrum weight (-0.98). Low to moderately heritability was observed for Brix score and colostrum weight in both breeds making them receptive to genetic selection in order to improve breeding programs. In conclusion, mode of birth significantly impacted colostrum composition which had subsequent effects on abundance of rumen microbiota. Colostrum Brix and volume were impacted by breed, season, and interaction, and calf incidence of disease was impacted by colostrum composition and environment. Additionally, two factors influencing colostrum quality (Brix score and colostrum weight) were found to be low to moderately heritable and have moderate to strong genetic correlations to compositional traits. Strong significant relationships were also found between colostrum compositional traits and colostrum quality traits. Therefore, incorporating quality traits into breeding programs has the potential to influence compositional traits which, in turn, can impact calf health and development by the interactions that exist between composition and microbial abundance in the rumen. / Master of Science in Life Sciences / Factors like breed, age, parity, nutrition, environment, and management can affect the quality of early milk produced. Many of these factors have been studied and guidelines developed in order to ensure producers feed the best quality milk to their calves which will allow for calves to develop properly. However, there is still a high mortality rate in pre-weaned calves and factors like mode of birth and genetics have not been readily studied. The purpose of our studies were to determine mode of birth impacts on composition of early milk and establish relationships between composition and rumen microbial phyla abundance. Additionally, establish relationships between colostrum composition traits, management practices, and calf health, and determine heritability and genetic correlations of colostrum quality traits to test-day composition traits. Our hypothesis was that colostrum quality traits such as Brix score and colostrum weight are heritable. We also hypothesized that mode of birth influences early milk composition and changes to composition has secondary effects to calf rumen microbial abundance. Charolaise (CHAR; n = 23) and Angus (ANG; n = 15) dams were divided into two experimental groups; dams underwent vaginal (VD; n= 25) or cesarean (CD; n= 13) delivery. Early milk samples were collected and sent to DHIA to quantify components. After parturition calves were separated based on dam's experimental group. Rumen fluid was collected from calves on d 1, 3, 28 post-partum and DNA extracted from fluid (ANG calves, n=11; CHAR calves, n=13). Results showed that VD significant differences in composition of VD and CD cows. Dams in VD group were more likely to have increased (P  0.05) protein, solids non-fat, and lactose but decreased (P < 0.05) urea concentrations. Similarly, short, medium, and long-chain fatty acids were increased (P  0.05) in VD. Changes in true protein elicited a decrease (P  0.05) in rumen fluid Actinobacteria and Proteobacteria. Results suggest that mode of birth influences protein concentrations in early milk and induces a slight impact on the overall dynamics of the calf rumen microbiome. A second study was conducted to establish relationships between colostrum components, management and calf health as well as determine genetic parameters of colostrum quality traits. Holstein (HO, n= 250) and Jersey (JE, n=289) cow test-day data was obtained from the Animal Genomic and Improvement laboratory server at the USDA. Brix score, colostrum weight, dam age, parity, and 3-month season of calving were also recorded. Colostrum samples from JE cows were sent to DHIA where compositional measurements were obtained (i.e. true protein, fat, lactose, SCS, solid non-fats). Lactoferrin concentration for JE cow colostrum samples was also determined via ELISA. Calf blood samples were collected within 72 h post-partum and TSP quantified. Farm staff recorded colostrum source for 1st feeding and colostrum freshness for 1st and feeding. A PROC Mixed was performed to determine impact of test-day milk composition traits on colostrum quality traits by breed, PROC Mixed with LSMEANS was used to determine relationships of environment, colostrum management, and colostrum components with incidence of scours and respiratory disease in calves. A Pearson correlation was used to determine relationships between colostrum components and quality traits Heritability and repeatability's were calculated using BLUPF90 family of programs. A series of bivariate models were used to calculate genetic correlations of Brix score and colostrum weight with test-day compositional traits. Results indicated that colostrum Brix and volume were impacted by season, breed, and the interaction of breed and season. Calf incidence of disease was impacted by colostrum components and total serum protein levels. Results for Pearson correlation indicated strong correlations between true protein and solid non-fats and Brix (r = 0.99; 0.86). Lactoferrin also had moderate negative correlations with volume and lactose (r = -0.35; -0.33). Heritability estimates results for Holstein Brix and colostrum weight were 0.25 and 0.15. Jersey cow heritability estimates were 0.36 and 0.47, respectively. We also observed some significant genetic correlations with Holstein Brix score and test-day milk (-0.23), fat (0.54), and SCS (0.29) having moderate correlations. Holstein colostrum weight had a strong correlation with test-day milk (0.96). Jerseys had strong genetic correlation of Brix score with colostrum weight (-0.98). Results indicated a low to moderately heritability for Brix score and colostrum weight in both breeds making them receptive to genetic selection in order to improve breeding programs. Strong significant relationships were also found between colostrum compositional traits and colostrum quality traits.

From Cache Valley Dairy Association in Smithfield, Utah, milk from two to three cheese vats plus the corresponding Swiss cheese trimmings, salted cheese, and whey were sampled each week from October 1981 to October 1982. The weights of the Swiss Cheese were recorded. Milk samples were analyzed for fat and protein; cheese samples were analyzed for fat, protein, and moisture; whey samples were analyzed for fat. By using Gauss-Newton nonlinear Least Squares method of iteration, the data was analyzed. Two formulas for predicting Swiss cheese yield were derived. A good relationship was found to exist between Swiss cheese yield and fat and protein. In this study it was found that the season affected the percentage of fat and protein in the milk and thereby the cheese yield. The highest cheese yields corresponded with the months with highest protein and fat percentage in the milk.