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Item Heritabilities and genetic and phenotypic correlations for milk production and fertility traits of spring-calved once-daily or twice-daily milking cows in New Zealand(Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association, 2023-03) Jayawardana JMDR; Lopez-Villalobos N; McNaughton LR; Hickson REThe objectives of this study were to estimate the genetic and phenotypic correlations and heritabilities for milk production and fertility traits in spring-calved once-daily (OAD) milking cows for the whole season in New Zealand and compare those estimates with twice-daily (TAD) milking cows. Data used in the study consisted of 69,252 first parity cows from the calving seasons 2015-2016 to 2017-2018 in 113 OAD and 531 TAD milking herds. Heritability estimates for production and fertility traits were obtained through single-trait animal models, and estimates of genetic and phenotypic correlations were obtained through bivariate animal models. Heritability estimates of production traits varied from 0.26 to 0.61 in OAD and from 0.13 to 0.63 in TAD. Heritability estimates for fertility traits were low in both OAD and TAD milking cow populations, and estimates were consistent (OAD: 0.01 to 0.10 and TAD: 0.01 to 0.08) across milking regimens. Estimates of phenotypic and genetic correlations among production traits were consistent across populations. In both populations, phenotypic correlations between milk production and fertility traits were close to zero, and most of the genetic correlations were antagonistic. In OAD milking cows, genetic correlations of milk and lactose yields with the start of mating to conception, 6-wk in-calf, not-in-calf, and 6-wk calving rate were close to zero. Interval from first service to conception was negatively genetically correlated with milk and lactose yields in OAD milking cows. Protein percentage was positively genetically correlated with 3-wk and 6-wk submission, 3-wk in-calf, 6-wk in-calf, first service to conception, 3-wk calving, and 6-wk calving rate in the TAD milking cow population, but these correlations were low in the OAD milking cow population. Further studies are needed to understand the relationship of protein percentage and fertility traits in the OAD milking system. The phenotypic correlations between fertility traits were similar in OAD and TAD milking populations. Genetic correlations between fertility traits were strong (≥0.70) in cows milked TAD, but genetic correlations varied from weak to strong in cows milked OAD. Further research is required to evaluate the interaction between genotype by milking regimen for fertility traits in terms of sire selection in the OAD milking cow population.Item Understanding the Effects of Lactose Hydrolysis Modeling on the Main Oligosaccharides in Goat Milk Whey Permeate(MDPI (Basel, Switzerland), 2019-09-10) Thum C; Weinborn V; Barile D; McNabb WC; Roy NC; Leite Nobrega de Moura Bell JM; Moreno DA; Villaño DEnzymatic hydrolysis of lactose is a crucial step to improve the efficiency and selectivity of membrane-based separations toward the recovery of milk oligosaccharides free from simple sugars. Response surface methodology was used to investigate the effects temperature (25.9 to 54.1 °C) and amount of enzyme (0.17 to 0.32% w/w) at 1, 2, and 4 h of reaction on the efficiency of lactose hydrolysis by Aspergillus oryzae β-galactosidase, preservation of major goat whey oligosaccharides, and on the de-novo formation of oligosaccharides. Lactose hydrolysis above 99% was achieved at 1, 2, and 4 h, not being significantly affected by temperature and amount of enzyme within the tested conditions. Formation of 4 Hexose (Hex) and 4 Hex 1 Hex and an increased de-novo formation of 2 Hex 1 N-Acetyl-Neuraminic Acid (NeuAc) and 2 Hex 1 N-Glycolylneuraminic acid (NeuGc) was observed in all treatments. Overall, processing conditions using temperatures ≤40 °C and enzyme concentration ≤0.25% resulted in higher preservation/formation of goat whey oligosaccharides.Item Modeling daily yields of milk, fat, protein, and lactose of New Zealand dairy goats undergoing standard and extended lactations(Elsevier Inc on behalf of the American Dairy Science Association, 2024-03) Boshoff M; Lopez-Villalobos N; Andrews C; Turner S-AThis study aimed to assess the milk production data for New Zealand dairy goats in either a standard lactation (SL; ≤305 d in milk [DIM]) or extended lactation (EL; >305 and ≤670 DIM) using a random regression (RR) with third- and fifth-order Legendre polynomials, respectively. Persistency of EL was defined as (B/A) × 100, where A was the accumulated yield from d 1 to 305, and B was the accumulated yield from d 366 to 670. On average, goats in SL produced 1,183 kg of milk, 37 kg of fat, 37 kg of protein, and 54 kg of lactose. The average production of milk, fat, protein, and lactose in EL were 2,473 kg, 78 kg, 79 kg, and 112 kg, respectively. The average persistences for milk, fat, protein, and lactose yields during EL were 98%, 98%, 102%, and 96%, respectively. The relative prediction errors were close to 10% and the concordance correlation coefficients >0.92, indicating that the RR model with Legendre polynomials is adequate for modeling lactation curves for both SL and EL. Total yields and persistency were analyzed with a mixed model that included the fixed effects (year, month of kidding, parity, and proportion of Saanen) as covariates and the random effects of animal and residual errors. Effects of year, month of kidding, and parity were significant on the total yields of milk, fat, protein, and lactose for both SL and EL. The total milk yield of first-parity goats with SL was 946 kg and the total milk yield of second-parity goats with SL was 1,284 kg, making a total of 2,230 kg over 2 years. The total milk yield of a first-parity goat with EL was 2,140 kg. Thus, on average, a goat with SL for the first and second parity produced 90 kg more milk than a first-parity goat subjected to EL. However, a second-parity goat subjected to EL produced 43 kg more milk (2,639 kg) than a goat with SL following the second and third parity (1,284 kg + 1,312 kg). These data, along with the various other benefits of EL (e.g., fewer offspring born and reduced risk of mastitis, lameness, and metabolic problems in early lactation), indicate that EL as a management strategy holds the potential to improve dairy goat longevity and lifetime efficiency without compromising milk production.Item Directional amorphous lactose crystallization : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Bioprocess Engineering at Massey University, Manawatu, New Zealand(Massey University, 2018) Ibell-Pasley, NicholasIt was proposed that during industrial drying of lactose crystals a surface layer of amorphous lactose may be formed in a flash drier and then crystallized during fluid bed drying. This crystallization is hypothesized to occur in one of two directions depending on the conditions, inside-out resulting in a dry product, and outside-in trapping moisture. In the inside-out case the moisture is driven outside the product, in the outside in case this moisture would be contained by a surface layer of crystalline lactose The trapped moisture from the outside-in case is proposed to slowly diffuse through the crystal layer during storage and cause handling problems, explaining observed differences between industrial products. To investigate this scenario the crystallization of amorphous lactose was modelled, and crystallization trials were conducted to try and achieve inside-out and outside-in crystallization. William-Landel-Ferry (WLF) and Arrhenius type kinetics were found to fit literature data for amorphous crystallization. Predictions made using these models showed that amorphous lactose crystallization under the high temperature conditions in a fluid bed dryer was possible. A method for isolating the enthalpy change associated with crystallization of amorphous lactose from simultaneous thermal analysis data was developed. This method shows promise for observing the crystallization process, but it may not be suitable for amorphous lactose quantification. Two methods were designed to achieve inside-out and outside-in crystallization of amorphous lactose. This required the temperature and water activity conditions to be precisely and independently controlled in lab trials. Simultaneous thermal analysis was used to monitor the crystallization of amorphous lactose samples under these conditions. Following the simultaneous thermal analysis, the samples were monitored for moisture release. Both the inside-out and outside-in crystallized samples were observed to slowly release moisture, increasing the measured relative humidity above the expected equilibrium value. Afterwards the samples were analysed and found to still contain low levels of amorphous lactose. The source of the rise in relative humidity could not be definitively attributed to either trapped moisture or ongoing crystallization but would not be expected had crystallization not been induced. Based on these findings it is recommended that a lactose crystal fluid bed drier is operated at conditions which would not allow for amorphous lactose crystallization. These conditions could be determined using the kinetic models fitted here.Item Lactose smearing in transport lines : a thesis presented in partial fulfilment of the requirements for the degree of Masters in Process Engineering at Massey University(Massey University, 2002) Mcleod, JeremyThe smearing of lactose in pneumatic conveying lines, leads to cakes of lactose building up within the lines. This is an undesirable situation as it leads to reduced throughput, caused by the narrowing of the lines and the increase in downtime required to unblock and clean the pipes. This study was carried out to investigate the causes of smearing and identify solutions to this problem. Impact testing was carried out, to look at the breakage behaviour of lactose. This identified that energy of impact is the main consideration for the breakage of lactose in pneumatic conveying. This is not only the energy contained before impact, but also the way in which the energy is dissipated during contact. The use of rubber proved an effective technique in lowering the amount of breakage, due to its ability to adsorb and disperse the impact energy during contact. Testing was carried out looking at the ability of sliding contact to cause the adhesion of lactose to a surface. The results showed that combination of the frictional forces and the sliding velocity can provide enough energy to cause the lactose to adhere. The conclusion drawn was the same as that for impact testing, with energy being the main consideration in the breakage and adhesion of lactose to surfaces. A link between amorphous lactose formation and the smearing was found, with the build up in the conveying lines having a higher amorphous concentration than was found on the free flowing lactose powder. An attempt to show a change in the amorphous concentration of α-lactose crystals after impact proved unsuccessful, although the use of a polarised microscope showed the formation of amorphous lactose on the impact surface. Calculations looking at the amount of amorphous lactose that would have formed after impact, identified that the concentrations were below the levels measurable using the methods available. Following on from impact testing work, a rubber lined bend was placed in a section of the conveying line at Lactose New Zealand. Monitoring of this bend showed it to be successful in preventing the adhesion of lactose to walls of the conveying pipe. However, there was a small amount of wear observed at the entrance of the bend. This was concluded to be due to a design defect as the rubber was raised above the level of the main line. More testing needs to be done, with a change in design, to allow a conclusion on the applicability of rubber for preventing lactose buildup to be drawn.Item Lactose fouling of ion exchange technology : a thesis presented in partial fulfilment of the requirements for the Masterate of Technology in Process Engineering at Massey University(Massey University, 1999) Smith, Antony CraigCheese whey is an ingredient used in infant formulae manufacture. Before addition, the cheese whey is fully demineralised using Ion Exchange (IE) technology. Investigation of the IE process revealed low lactose yields. The objective of this thesis was to provide an understanding of the mechanism causing these low yields. This understanding may be used to improve these yields during IE processing. Two mechanisms were proposed for the removal of lactose during IE processing namely resin entrapment and lactose mutarotation adsorption. Investigations of the mechanisms were performed with both continuous and batch benchtop methods. Whey, lactose and DMSO/lactose feed solutions were employed with various resins. DMSO/lactose solution experiments were inconclusive in determining the mechanism. Whey and lactose trials revealed lactose adsorption occurred predominantly onto the macroporous anion resin (0.09 g-lactose/g resin) compared with the gel cation resin (0.04 g-lactose/g resin). In comparison the maximum lactose adsorption onto an alternative gel structured anion resin was shown to be 0.05 g-lactose/g resin. Absorption isotherm results were dependent on the supernatant concentration. The majority of lactose adsorbed onto both the macroporous and gel anion resins was recovered with six and three equivalent volumes of water, respectively. The adsorption dependency on the resin structure and supernatant concentration coupled with the recovery of adsorbed lactose with water proved that the resin entrapment mechanism was causing the low lactose yields. In hindsight the DMSO results were also consistent with the resin entrapment mechanism causing the low lactose yields. It is recommended that to reduce lactose losses during IE processing by 43%, gel structured anion resin (A847S) should be coupled in series with the existing gel structured cation resin (C100H). The gel anion resin would also halve the anion water requirements during lactose recovery flushing.Item Inhibition of the lactose to ethanol fermentation of Kluyveromyces marxianus Y113 and attempts at its alleviation through media improvement : a thesis presented to Massey University in fulfillment of the thesis requirement for the degree of Master of Technology(Massey University, 1991) Grubb, Christopher FrancisInhibition of the lactose to ethanol fermentation of K.marxianus Y113 was investigated. The use of initial lactose concentrations of 150 g/litre or greater resulted in less biomass accumulation, lower ethanol productivity and incomplete substrate utilisation. Keeping the initial lactose concentration at 100 g/litre but increasing the medium osmolality by up to 5 times via the addition of non-utilised salt or maltose resulted in substantially reduced biomass accumulation and slightly lower ethanol productivity. This suggested that high medium osmolality inhibits the yeast in a non-specific way by increasing the energy required for cell maintenance at the expense of biomass production. Keeping the intial lactose concentration at 100 g/litre but adding up to 5% (by weight) ethanol reduced the amount and rate of biomass accumulation and led to incomplete substrate utilisation, as well as dramatically lowering the amount of ethanol produced by the least itself. The detrimental effects of added ethanol became significant only when more than 2 to 3% (by weight) was added. A maximum alcohol concentration of 4 to 5% (by weight) was observed in all cases, irrespective of the concentration of ethanol added initially. These results suggested that the ethanol inhibited the energy metabolism of the cell in some specific way and did not merely increase the requirement for cell maintenance energy. In the concentrations tried supplementation of the medium with yeast extract, magnesium, calcium and chitin all failed to produce any change in the performance of the fermentation. Supplementation with still bottoms was found to be quite strongly inhibitory to the fermentation. Demineralisation of the whey permeate medium reduced that the performance of the fermentation compared to that carried out on standard whey permeate medium. K.marxianus Y113 was able to ferment a medium of defined composition but the biomass growth, ethanol productivity and lactose utilisation were not as good as those achieved using complex media such as whey or lactose broth. increasing the concentration of nutrients in the defined medium was of small benefit but the performance was still well below that seen on complex media.Item A genetic and economic evaluation of lactose in the New Zealand dairy industry : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science(Massey University, 2016) Sneddon, Nicholas WilliamMilk composition in New Zealand is heavily influenced by the selection for Breeding Worth (BW) and the breed composition of the national herd. Under selection for BW a greater emphasis is placed upon protein (39% of emphasis) than fat yield (13% of emphasis) with a penalty on milk volume (14% of emphasis). The export orientated product portfolio influences the development of economic values for fat and protein in the BW, to date lactose has not been considered despite its importance in the manufacture of whole milk powder (WMP). The milk produced on farm is in deficit for lactose based on the current export product portfolio. This thesis evaluated the potential of altering New Zealand milk through the modification of the selection objective around milk lactose selection. Genetic parameters were estimated including lactose yield to construct selection objectives and indices to evaluate the effect on lactose production under a number of different product portfolio scenarios. Genetic parameters were estimated from daily and total milk records with moderate heritabilities found for both lactose yield and lactose content. The genetic correlations between lactose yield and milk volume was estimated to be 0.98, which is a potential problem as this correlation effectively gives lactose a negative economic value due to the negative value on milk volume. Using an existing industry milk processing model, the lactose deficit was estimated to be 129,000 tonnes in 2012 which is consistent with industry records. A genetic gains model developed from this thesis, combined with an existing industry model estimated that the deficit in lactose would increase by 60%, to 204,000 tonnes by 2022 if no changes were made to the current selection objective and index. Including lactose yield in the selection objective with an economic value of $2.04, 14.7% relative emphasis within the objective, would reduce the lactose deficit by 8.7% to 194,000 tonnes. Overall the results of this thesis indicate that including lactose yield in the selection objective has the potential to modify the composition of milk to make it more suitable for the production of WMP and increase the potential for profit in the industry.Item Development of a continuous process to produce the 1:1 [beta]/[alpha] mixed lactose crystal : a thesis in partial fulfilment of the requirements for the degree of Master of Engineering at Massey University(Massey University, 2007) Anantpure, PreyasA new lactose crystal was formed at Massey University in 1997 while studying the effects of superheated steam on the production of β-lactose. The crystal typically had 50-52% β-lactose content and an X-ray diffraction pattern that did not match with either β-lactose or β-lactose monohydrate, and so it was thought to be an entirely new lactose crystal. Preliminary work was then done at Massey University to determine the conditions under which the crystal could be produced. The new crystal was produced in a batch process in a superheated steam environment between the temperatures of 125°C to l55°C and at very fast drying rates. The present work attempts to develop a continuous process to produce this new lactose crystal. During the late stages of the project it was found that a similar crystal was already documented in the literature and its crystal structure defined. So the crystal found at Massey University could not be termed as a new crystal. The crystal found in the literature was formed by a high thermal treatment to solid-state β-lactose monohydrate and amorphous lactose and had a β/α anomeric ratio of 1:1. The present work attempts to develop a continuous process to produce the 1:1 β/α mixed lactose crystal from a liquid state and in a superheated steam environment. A roller drier was thought to be the best option to produce the new crystal in a continuous process. Different arrangements were developed to create the required conditions under which it was expected that the 1:1 β/α mixed lactose crystal would be produced. Lactose solution sprayed on the roller drier using spray nozzles at temperatures of 125°C to 155°C and flow rates in the range of 1lOml/min to 40ml/min with varying drum speeds consistently produced 85% β-lactose. Lactose solution was smeared on the drum surface which also produced about 80% β-lactose. Lactose solution that was sprayed over a tray which was designed to allow only small amount of the solution (about 3ml/min) to pass through produced about 58% β-lactose. X-ray diffraction showed that the crystal was a mixture of 1:1 β/α mixed lactose crystal and β-lactose crystal. This confirmed that, to produce the 1:1 β/α mixed lactose crystal very low flow rates were required (1.5ml to 3ml/min flow rate). It was observed that the 1:1 β/α mixed lactose crystal was formed when the lactose solution formed a rubbery amorphous lactose solution and then quickly crystallized in the superheated steam environment. To confirm this hypothesis, spray dried amorphous lactose was crystallised over the roller dried inside the superheated steam environment at 125°C, 135°C and 145°C. The resulting product was a mixture of the 1:1 β/α mixed lactose crystal and β-lactose crystal. To produce an amorphous phase from the solution, the solution was injected in air for a few seconds before introducing it into the superheated steam environment. Lactose solution at 90 °C injected onto the roller with a temperature of 145°C for 10 sec in air and 15 minutes in superheated steam produced a crystal having a structure different to that of a β-lactose crystal or α-lactose crystal and it had a similar X-ray diffraction pattern to that of the 1:1 β/α mixed lactose crystal documented in the literature and the crystal formed at Massey in 1997. It was also shown that in the absence of superheated steam, β-lactose crystals were formed. It was clearly shown that a noticeable amount of the 1:1 β/α mixed lactose crystals are formed in products having β-lactose contents below 60%. The formation of 1:1 β/α mixed lactose crystal was found to be very problematic and thus the results were not repeatable. Further investigation should be carried out with better control of all the parameters. Moisture content (mc) was thought to be a contributing factor that needs to be investigated further.Item Lactose hydrolysis by immobilized whole cells of K. lactis CBS 2357 : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Bioprocess Engineering at Massey University(Massey University, 1999) Marasabessy, AhmadThe application of immobilized yeast for lactose hydrolysis was investigated. The enzyme stability was tested as a function of pretreatment. The stability of K. lactis CBS 2357 cells after treatment with glutaraldehyde (GA) and the β-galactosidase activity of whole cells after immobilization in alginate bead and corn particles were studied. Permeabilization using ethanol and chloroform (10% and 2%, respectively) at 37 °C and 120 rpm for 5 min, followed by stabilization with 10 mM glutaraldehyde at 30 °C for 1 hour with gently shaking deactivated 2.5% of the initial whole cells β-galactosidase activity, tested with the ONPG method. The glutaraldehyde treatment could significantly maintain β-galactosidase activity in phosphate buffer pH 6.5 containing 0.1 mM MnCl2. Manganese and potassium ions in the Mn-Buffer were found to be essential to enhance the activity. The biomass activity of GA stabilized cells in Mn-Buffer can be maintained above 70% during 72 hours of incubation at 30 °C. An increase of incubation temperature from 30 to 37 °C deactivated 10% of biomass activity after 72 hours. Direct stabilization of alginate biocatalyst with glutaraldehyde caused a significant reduction of β-galactosidase activity with the resulting deactivation depending on glutaraldehyde and alginate concentrations. When 40 g of biocatalyst containing 2x109 cells/g alginate was stabilized in 100 ml of 0 to 4 mM glutaraldehyde, the optimum range of glutaraldehyde concentration was between 0.5 to 1.0 mM. When this concentration range was applied to stabilize 2%- to 3%-alginate biocatalyst, the average biocatalyst activity remained within 56-74% of the initial activity. It was shown that the adsorption of K. lactis on corn particles through a "double liquid cultivation stage" followed by permeabilization of biocatalyst gave a higher activity. The activity obtained was 0.84 μmol lactose hydrolyzed /min/g biocatalyst under the conditions tested. This activity was about 5 times higher than the case without permeabilization and about 2 times higher than that of the permeabilized biocatalyst prepared with a "single liquid cultivation stage". When tested in the packed-bed reactor, during the initial stages the degree of hydrolysis (d.h.) was 45% within the operational conditions tested. Free enzyme was detected during the first 5 hours of operation, especially when non-stabilized corn biocatalyst was used. After 5 hours, free enzyme was no longer detected in the reactor outlet, suggesting that direct adsorption might have rendered good cell confinement inside the corn particles.