Higher Milk Fat Content Research Articles

Productive performance and milk composition of dairy ewes supplemented with corn silage (Zea mays L.), sunflower (Helianthus annuus) silage and their mixture.

The work reported in the Research Communication investigated in vitro rumen gas kinetics and fermentation profile as well as in vivo performance of lactating ewes fed corn silage (CS), sunflower silage (SFS) and their 50 : 50 mixture (CS-SFS). For the in vivo experiment, nine early-lactation Suffolk × Texel ewes were grouped in a replicated 3 × 3 Latin square design of three 21-d periods. Treatments were based on ad libitum CS, SFS, and CS-SFS supplemented with concentrate at 48 g/kg LW0.75. In vitro results showed that the CS had the highest dry matter degraded substrate and microbial crude protein production followed by CS-SFS. The in vivo data showed that animals fed on CS had higher digestibility of dry matter and organic matter than CS-SFS, while SFS were intermediate. Nitrogen (N) intake, fecal N excretion, and urine N excretion were similar between groups, however, milk N excretion was lower in SFS than CS. Milk yield was higher for CS and CS-SFS than SFS group, however, SFS-fed ewes had higher milk fat content than either CS or CS-SFS (all differences reported here were significant, P < 0.05 or better). Overall, CS-SFS could be used as dietary roughage for dairy ewes without deleterious effects on nutrient intake, N-balance and milk yield whilst potentially offering a more sustainable alternative to CS.

Impact of milking interval and time on milk spontaneous lipolysis and composition in dairy cows

Milk lipolysis is defined as the hydrolysis of triglycerides, the major component of milk fat, resulting in the release of short-chain fatty acids (FA) responsible for rancid flavor and partial glycerides that impair functional properties such as foaming and creaming abilities. Milk lipolysis is a complex phenomenon that depends on both animal parameters and breeding factors. Milk spontaneous lipolysis is known to be higher in milk from evening milkings than from morning milkings. This may be related to the longer length of overnight milking intervals or to the nycthemeral cycle. In this experiment, our objective was thus to study the impact of both milking intervals and time of day on milk spontaneous lipolysis in twice-daily-milking systems with one of 3 milking intervals: Short Day - Long Night (SD-LN, 6.30 a.m. and 4.30 p.m.,); Long Day - Short Night (LD-SN, 6:30 a.m. and 8:30 p.m.,); and Balanced Day and Night (BDN, 6:30 a.m. and 6:30 p.m.,). To achieve this goal, 21 multiparous dairy cows in mid-lactation were used in a 3 × 3 Latin square design over 3 periods. The experiment lasted 5 weeks, corresponding to 3 experimental periods of 6 d alternating with 8 d of milking with conventional hours (morning-evening gap of 10 h). We confirmed that milk spontaneous lipolysis was influenced by milking interval, but not the milking time. Indeed, we observed more lipolysis in SD-LN evening milk (+0.20 mEq/100 g fat) and LD-SN morning milk (+0.22 mEq/100 g fat), both of which corresponded to a 10 h interval between successive milkings. High lipolysis milk came from cows that produced less milk with a higher milk fat content. No significant difference between milkings was observed for BDN. Milk protein, total P and citrate contents increased according to the duration of mammary gland storage of milk (from 10 to 14 h). There was no effect of milking intervals on milk fat globule diameter. The milk Na+/K+ ratio, indicating an opening of tight junctions in the mammary gland, increased only in evening milkings with BDN and LD-SN. In conclusion, we found that the effect of milking intervals on lipolysis is stronger than that of the nycthemeral cycle.

Effects of Brown Seaweed (Ascophyllum nodosum) Supplementation on Enteric Methane Emissions, Metabolic Status and Milk Composition in Peak-Lactating Holstein Cows.

The dairy industry contributes significantly to anthropogenic methane emissions, which have an impact on global warming. This study aimed to investigate the effects of a dietary inclusion of brown seaweed Ascophyllum nodosum on enteric methane emissions (EMEs), hematological and blood biochemical profiles, and milk composition in dairy cows. Eighteen Holstein cows were divided into three groups: CON (non-supplemented cows), BS50 (50 mL of 10% A. nodosum), and BS100 (100 mL of 10% A. nodosum). In each cow, measurements of EME, dry matter intake (DMI), and milk yield (MY), as well as blood and milk sampling with respective analyzes, were performed before supplementation (P1), after 15 (P2) days, and after 30 (P3) days of supplementation. A. nodosum reduced (p < 0.05) methane production, methane yield, and methane intensity in both BS50 and BS100, and raised DMI (p < 0.05) only in BS50. Total bilirubin (p < 0.05) was higher in BS50 compared to CON cows in P2, and triacylglycerols were lower (p < 0.05) in BS50 than in CON cows in P3. Higher milk fat content was found in BS50 than in CON cows in P3. C16:0 proportions were higher (p < 0.05) in BS50 and BS100 than in CON cows, while C18:3n-3 was higher (p < 0.05) in BS100 than in BS50 and CON cows in P3. Dietary treatment with A. nodosum reduced EMEs and showed the potential to increase DMI and to improve energy status as well as milk composition in peak-lactating dairy cows.

Продуктивность коров при разной комбинации линий

The purpose of the study was to study the milk productivity of cows with different combinations of lines. The object of the study were first-calf cows of the black-and-white breed of the line Vis Back Aidiala 101341, Reflection Soveringa 198998, Montvik Chiefteina 95679. Cows obtained by intraline selection of the Aidial line have a high level of milk productivity, with milk yield of 5571 kg of milk, milk fat yield of 226 kg and protein yield of 171 kg, while significantly (P&lt;0.05-0.01) superior to first-calf heifers, belonging to the Sovering line for 102 kg, 4 kg of fat and 4 kg of protein, and to the Chieftain line - for 259 kg of milk, 16 kg of fat and 11 kg of protein, respectively. When crossing the Ideal-Sovering lines, the highest milk yield is observed (5667 kg), with good milk fat content (4.01 %), high yield of milk fat (227 kg) and milk protein (172 kg). With the reverse cross Sovering-Idial, slightly lower milk productivity rates were obtained. When using bulls of the Aidial line on cows of the Governer line, high milk fat content (4.07 %) and milk fat yield (228 kg) were obtained, with average values of milk yield (5596 kg), protein mass fraction (3.01 %) and its yield (168 kg). Unsuccessful combinations of lines in both forward and reverse directions are crosses of the Idial and Chieftain lines. The descendants of such combinations have the lowest milk productivity. Thus, the use of line manufacturers R. Sovering and V.B. Idiala, both with intraline selection and interline combination, gives the best milk productivity indicators. Consequently, it is necessary to evaluate bulls according to the compatibility of lines; this has a great influence on the productivity of the offspring, since sires of the same line, when inseminating cows of the same lines, produce offspring of different productivity.

Evaluation of the Metabolic Relationship between Cows and Calves by Monitoring Calf Health and Cow Automatic Milking System and Metabolic Parameters.

With this study, we investigated the relationship between a cow's and calf's metabolic state, and its effect on health status. To achieve this, 20 calves of primiparous and 20 calves of multiparous cows were selected. The calves were monitored for 30 days and scored for signs of disease, as described in McQuirk (2008); according to score, they were divided into healthier calves; the Low calf score group (LCS, 5-8), Medium calf score group (MCS, 9-12) and High calf score group (HCS, 14-17); or calves most prone to disease. Their mothers were monitored for the same period with a Lely Astronaut 3 herd management system (Lely, Maassluis, The Netherlands) for rumination time, milk yield, milk fat, protein, lactose concentrations and milk fat to protein ratio. Both cows and calves were sampled for blood, and concentrations of glucose with β-hydroxybutyrate were registered. The results indicate that primiparous cows had a 16% higher blood glucose concentration (3.03 mmol/L SE = 0.093) compared with multiparous cows (2.61 mmol/L, SE = 0.102) (p < 0.01), but no difference in calf glucose was recorded. Β-hydroxybutyrate levels did not differ significantly between cows and calves by parity group. Rumination time was longest in the HCS group at 550.79 min/d. and was 16% longer compared with the LCS group (461.94 min/d.; p < 0.001) and 8% longer compared with the MCS group (505.56 min/d.; p < 0.001). The MCS group rumination time mean was statistically significantly higher compared with the LCS group by 8% (p < 0.001). Milk yield was also highest in the HCS group (44.8 kg/d.): 19% higher compared with the MCS group (36.31 kg/d., p < 0.001) and 13% higher than the LCS group (38.83 kg/d., p < 0.001). There was also a significant difference between the MCS and LCS groups of 6% (p < 0.001). The HCS group had the highest milk fat concentration (4.47%): it was 4% higher compared with the LCS group (4.28%, p < 0.001) and 5% higher than the MCS group (4.25%, p < 0.001). Milk fat to protein ratio was highest in the HCS group (1.21) and was 7% higher than in the MCS group (1.12, p < 0.001) and 8% higher than in the LCS group (1.11, p < 0.001). The LCS group was determined to have the highest concentration of milk lactose (4.66%). It was 1% higher compared with the MCS group (4.62%, p < 0.001) and 1.07% higher than the HCS group (4.61%, p < 0.001). We can conclude that parity did not affect calf health status and that cows of the HCS group showed symptoms of negative energy balance expressed through higher milk yield, higher milk fat concentration and higher milk fat to protein ratio, with lower milk lactose concentration. Further and more thorough research is needed to evaluate the relationship between pregnant cows and calves.

МОЛОЧНАЯ ПРОДУКТИВНОСТЬ КОРОВ, ПРОИСХОДЯЩИХ ИЗ ПЕРСПЕКТИВНЫХ ВЕТВЕЙ ГОЛШТИНСКОЙ ПОРОДЫ

The aim of the study was to study the milk productivity of cows originating from different promising branches and lines of the Holstein breed. The population studied was Wis Back Idial 101341, Reflection Sovering 198998, Montvik Chieftain 95679, Siling Traijun Rokita 252803 and Roseife City 267150. The best indicators were established in cows of the line V.B. Ideal for the 1st and 3rd lactation (7086 and 7431 kg of milk with the amount of milk fat 271 and 285 kg and the amount of milk protein 225 and 238 kg), and the difference is statistically significant (P&lt;0.05-0.001) in relation to other lines. In second place are the animals of the Reflection Sovering line. Cows of the line S.T. Rokita had a high milk fat content (3.85 and 3.94%) at P&lt;0.05. In V. Aidial's line, the best milk yield indicators are shown by first-calf heifers of the SWEET-HAVEN TRADITION branch (7143 kg). In the R. Sovering line, cows of the TO-MAR BLACKSTAR-ET branch showed the greatest increase in milk yield by 89-1226 kg, milk fat yield by 4-42 kg, milk protein yield by 2-37 kg (P&lt;0.001), and high milk fat content (3.86%) of the cow of the S-W-D VALIANT line (P&lt;0.01-0.001). According to the 3rd lactation in the line of R. Sovering, cows of the S-W-D VALIANT branch show an advantage in milk yield by 353-831 kg of milk, mass fraction of fat - by 0.05-0.08%, milk fat yield - by 20-36 kg and milk protein yield - by 12-26 kg (P&lt;0.05-0.01). As a result of the study, it was found that the use of animal branches of SWEET-HAVEN TRADITION, ROCKALLI SON OF BOVA, TO-MAR BLACKSTAR-ET and WALKWAY CHIEF MARK makes it possible to obtain high milk productivity from them.

Survival and predictive modeling of Listeria monocytogenes under simulated human gastric conditions in the presence of bovine milk products

Listeria monocytogenes is an opportunistic foodborne pathogen which has been implicated in many outbreaks of foodborne diseases. This study evaluated the effects of gastric acidity and gastric digestion time of adults, L. monocytogenes strain and food type on the survival of L. monocytogenes under simulated stomach conditions of adults in in vitro gastric models with dynamic pH changes occurring throughout the exposure. Individual strains as well as a cocktail of L. monocytogenes, inoculated at 8 log CFU/mL in filtered bovine milk products, 0 % milk, 2 % milk, 2 % chocolate milk and 3.25 % milk, were introduced to the gastric models for 2 h. The survival of L. monocytogenes depended on a combination of factors, including gastric acidity and gastric digestion time of adults, L. monocytogenes strain, food type and recovery method (P < 0.05). The survival rates of L. monocytogenes inoculated in 2 % milk after a 2-h exposure to simulated gastric fluids with pH values of 1.5, 2.0 and 3.0 were 0.003 to 0.040 %, 22.7 to 43.4 % and 16.6 to 27.2 %, respectively. Fluid milk containing a higher milk fat content (3.25 % vs 0 % milk) protected L. monocytogenes from being inactivated when they were exposed to the human stomach model with a gastric acidity of pH 2.0. Compared to 0 % and 3.25 % milk, L. monocytogenes survived the best in 2 % chocolate milk, which appears to be due to the presence of milk fat (2 %) and the additional nutrients that are present in chocolate milk. A predictive mathematical model was developed that captured the population of the strains of L. monocytogenes under the in vitro conditions. This study advances our understanding of the behaviour of L. monocytogenes under various human gastric conditions and provides key parameters that can affect the survival of L. monocytogenes in the stomachs of adults. The mathematical models developed in this study can be used as a supplementary tool to help predict the survival of L. monocytogenes under similar scenarios and for relevant risk-assessment studies.

Formation of signs of milk productivity of cows depending on their origin by father

When breeding dairy cattle, productivity is of the greatest economic and economic importance. A sufficient number of highly productive animals and their effective use in herds reveals the breed's potential, contributes to increasing the genetic potential of cows and the effectiveness of selection and breeding work as a whole. At the same time, it should be noted that according to many scientists, fathers of cows have the most significant influence on the formation of signs of milk productivity. In dairy cattle breeding, about 90 % of the genetic progress of the population is provided by bulls. However, the research of different farms shows that bulls do not have the same effect on the productivity of their daughters. Therefore, it must be taken into account when planning work on improving the productive qualities of dairy cattle. In view of the above, the goal of our research was to find out the influence of bulls on the formation of milk productivity of daughters in different farms. The research was carried out in farms located in different climatic zones of Ukraine, namely: in the SE EF “Olexandrivske” in Vinnytsia region (Forest Steppe zone, n = 714), LLC AE “Imeni Volovikova” in Rivne region (Polyssia zone, n = 1840) and SE “Experimental farm “Askaniyske” (Steppe zone, n = 926) on first-calf heifers and adult cows (III lactation) of the Ukrainian Black-and-White dairy breed. It was established that during the first lactation, the highest milk yield and milk fat output in the SE Oleksandrivske were characterized by the daughters of the bull Dzhorin (6936 and 248.9 kg), during the third – the daughters of the bull Detektiv (8148 and 295.2 kg), and the most fat-milk the above lactations were, respectively, daughters of Zhames (3.68 %) and S. Aristotl (3.63 %). In LLC AE “Imeni of Volovikova” the daughters of the bull R. Baltimor (7509 and 7486 kg and 267.8 and 281.9 kg, respectively) had the highest milk yield and milk fat output for the two studied lactations, daughters of Derbi (3.74 %) for the first lactation had the best indicators of fat content in the milk, for the third – daughters of Tirs (3.64 %). In the SE "Experimental Farming “Askaniyske” first-calf heifers – daughters of N. Bolt were the most productive (7348 kg), in terms of milk fat output - daughters of Surguch (292.2 kg), and in terms of milk fat – daughters of Latur (4.31 %). The highest productivity during the third lactation was observed in the daughters of the bull Akord (8,329 kg of milk fat, 320.8 kg of milk fat), and the highest milk fat content was observed in the daughters of Polarshtern (4.37 %). The influence of bulls on the fertility of cows in controlled farms was in the range of 14.9–46.2 %, on the fat content in milk - in the range of 7.4–20.2 %.

Transcriptome Profile in Dairy Cows Resistant or Sensitive to Milk Fat Depression

Feeding linseed to dairy cows results in milk fat depression (MFD), but there is a wide range of sensitivity among cows. The objectives of this study were to identify target genes containing SNP that may play a key role in the regulation of milk fat synthesis in cows resistant or sensitive to MFD. Four cows were selected from a dairy farm after a switch from a control diet to a linseed-rich diet; two were resistant to MFD with a high milk fat content in the control (4.06%) and linseed-rich (3.90%) diets; and two were sensitive to MFD with the milk fat content decreasing after the change from the control (3.87%) to linseed-rich (2.52%) diets. Transcriptome and SNP discovery analyses were performed using RNA-sequencing technology. There was a large number of differentially expressed genes in the control (n = 1316) and linseed-rich (n = 1888) diets. Of these, 15 genes were detected as key gene regulators and harboring SNP in the linseed-rich diet. The selected genes MTOR, PDPK1, EREG, NOTCH1, ZNF217 and TGFB3 may form a network with a principal axis PI3K/Akt/MTOR/SREBP1 involved in milk fat synthesis and in the response to diets that induced MFD. These 15 genes are novel candidate genes to be involved in the resistance or sensitivity of dairy cows to milk fat depression.

ANALIZA PRODUKCYJNOŚCI I WSKAŹNIKÓW ROZRODU KRÓW RASY POLSKIEJ HOLSZTYŃSKO-FRYZYJSKIEJ W TRZECH KOLEJNYCH LAKTACJACH

The aim of the research was to determine the productivity and reproduction indices of the Polish Holstein-Friesian Black-and-White variety cows in three consecutive lactations. The research was carried out in the Experimental Station of the National Research Institute Kołbacz on the Dębina farm. The herd of 1025 cows were kept in free-stall barns and fed with TMR system. The yield (kg) of milk, FCM milk, protein and fat was analyzed; content (%) of protein and fat and selected reproductive parameters such as age at the first calving, as well as inter-pregnancy periods and calving interval, period service, postpartum downtime in three consecutive 305-day lactations. The studies indicated that the average yield of milk, fat and protein showed an increasing tendency in the next three lactations. The average protein and fat content were similar. The highest results of these ingredients were obtained in cows in the second lactation. Lactation efficiency influenced the value of the analyzed fertility indices. With the increase in cows’ productivity, the calving interval and inter-pregnancy period, including period service and postpartum downtime, were significantly longer. The longest calving interval and inter-pregnancy period were observed in the third lactation, and the shortest in the first lactation of cows. With the extended of the calving period, the yield of milk, protein, and fat increased. The age at the first calving was the lowest in the 2nd and the highest in the 3rd lactation. The cows calving first for the first time had the highest milk fat content and the shortest calving period. The service period was the longest in the 2nd lactation and occurred in cows with the highest fat content. Postpartum downtime in the studied herd of cows was the longest in the third lactation. The resting period was extended with the increase in the yield of: milk, FCM milk, protein and fat

Utilization of Wool Integral Lipids to Determine Milk Fat Content in Suffolk Down Ewes

The identification of higher fat content in ewe milk during lactation can help to improve the nutritional value and quality of the derived dairy products. In this study, we characterized fatty acids from the wool of Suffolk ewes at two time points during lactation and assessed whether they were related to milk fat content through discriminant analysis and, thus, could be potentially used to identify ewes with a high fat content. Eighty single-bearing Suffolk ewes of similar body weight, body score, and age were selected for this study. The overall fat contents of milk and wool were determined, as well as the fatty acids in the wool. The wool fat content was 1.14% on average. The proportions of wool fatty acids were 65.82% saturated, 21.70% monounsaturated, and 12.48% polyunsaturated fatty acids. The wool fatty acid concentrations of C18:1n9c, C18:2n6c, and C22:2 were higher in ewes whose milk had a high fat content at both time points. Moreover, the levels of these fatty acids were positively correlated with milk fat content. Discriminant analyses using C18:1n9c and C18:2n6c were the best candidates for the prediction of high milk fat content, with an accuracy of 87.50%. The wool fatty acids C18:1n9c and C18:2n6c could potentially be used to determine the milk fat content of ewes.

Single nucleotide polymorphism in STAT5A could not endorse variation in milk production traits in Indian bovine population.

The Signal Transducer and Activator of Transcription 5A (STAT5A) gene involved in activating the transcription of milk protein genes was predicted to be influencing milk production traits. The present study was undertaken to investigate the suitability of the polymorphism of STAT5A as a marker for milk traits in Ongole, crossbred cattle and Murrah buffaloes from Southern India. Blood samples (n = 502) for DNA isolation and milk samples (n = 222) from different genetic groups were collected from various farms. The gene variants upon polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) on the exon 7 region of STAT5A were subjected to GLM analysis to evaluate their association with milk production traits. The frequencies of C and T alleles at the STAT5A/AvaI locus were 0.98 and 0.02 (Jersey crossbred), 0.94 and 0.06 [Holstein-Friesian (HF) crossbred], 0.97 and 0.03 (Ongole). T allele was not observed in Murrah buffaloes. The least squares mean lactation milk yield of CC and CT genotypes of STAT5A were 2,096.90 ± 48.63 and 2,294.41 ± 215.85 kg in Jersey crossbred, 2,312.92 ± 91.01 and 2,392.82 ± 207.66 kg in HF crossbred and 528.40 ± 22.10 and 396.37 ± 76.17 kg in Ongole cattle, respectively. The milk fat content of the CC genotype was higher (P > 0.05) in Jersey crossbred cattle. The CT genotypes of Ongole and HF crossbred cattle recorded a higher fat per cent than the CC genotypes. Significant associations were not observed in support of STAT5A as a marker for milk production traits in either Ongole or crossbred cattle of indicine admixture and no reason could be found to consider this locus as universal markers for milk production traits in indicine cattle and buffaloes. Considering the monomorphic nature of the gene in buffaloes and their higher milk fat content as compared to bovine milk, much remains to be explored regarding the underlying differences across the bovine and the bubaline species.

Use of Holstein bulls in improvement of black pied cattle

Sires play an important role in improvement of productive qualities of bred livestock. Most researchers and breeders estimate their impact to be at least 90%. In order to evaluate the results of using different Holstein breeding bulls, we compared the productivity of their offspring with the average values for all bulls. The following methods of variation statistics were used: observation, data grouping, and correlation analysis. It was found that the best are the descendants of the bull Estuary 2186 of the Montwick Chieftain line. Besides, Liman 2186 bull’s daughters excelled in high milk fat content - 4.46%. Daughters of Punch 2748 bull of Pabst Governor line were the best in protein content of milk (3.27%). Daughters of Liman 2186 bull had the highest fat and protein yield during 305 days of lactation. It was established that the direction and value of correlation between the main features of milk yield of cows of different lineages have a rather high degree of variation. Presence of positive genetic correlation between milk yield and protein content in milk in some lines of animals enables breeding cows by two traits simultaneously (milk yield and protein content in milk).

Milk production, rumen function, and digestion in dairy cows fed diets differing in predominant forage and concentrate type

The objective was to determine the effect of dietary ratio of neutral detergent fibre (aNDFom) to starch within diets differing in grass to maize silage ratio on rumen function, diet digestion, serum haptoglobin, and production of lactating dairy cows. Four isonitrogenous diets were formulated with a forage to concentrate ratio of 50:50, with the forage proportion containing either a high or low ratio of grass silage to maize silage (82:18 [GS] or 18:82 [MS] on a dry matter [DM] basis, respectively) and the concentrates containing either a high (F) or low (S) aNDFom to starch ratio, giving 4 dietary ratios of aNDFom to starch. Diets were fed to 4 early lactation Holstein dairy cows in a 4 × 4 Latin square design with 28-d periods. Feed intake, eating behaviour, milk production and composition, total tract digestion, nitrogen (N) excretion, aNDFom passage rate and in-situ degradation, rumen pH, and serum haptoglobin were measured during the last week of each period. Cows fed the MS diets consumed 1.34 kg/d more DM (P = 0.047) and 2.38 kg/d more starch (P = 0.001) compared to GS diets and produced 2.46 kg/d more milk (P = 0.038). Milk fat concentration was higher (+2.88 g/kg) for cows fed GS diets compared to MS diets (P = 0.007), while cows fed S concentrates had a higher milk fat concentration (+1.8 g/kg) irrespective of forage source (P = 0.033). Digestibility of aNDFom was higher (+0.106 kg/kg) for GS diets than for MS diets (P = 0.004). Similarly, aNDFom digestibility was higher (+0.057 kg/kg) for F concentrates (P = 0.031). Rumen and total-tract particle retention times were higher (+11.9 and +9.1 h, respectively) for cows fed GS diets (P = 0.009 and P = 0.037, respectively). Milk N yield/N intake was higher for the MS diets versus GS diets (P = 0.045), due to a greater (+130 g/d) milk protein yield (P = 0.015). Cows fed the MS diets spent 187 min/d more with rumen pH below 5.8 compared to GS diets (P = 0.006). Serum haptoglobin concentration, a purported marker of gut inflammation, was 5.3 ng/ml higher for cows fed S concentrates versus F concentrates (P = 0.023). In conclusion, changes in concentrate aNDFom:starch ratio had little effect on DM intake, milk yield and composition, rumen function, and eating behaviour compared to effects of silage source (MS vs GS), where replacing a portion of diet GS with MS increased feed intake, milk yield, rumen passage rate, and N digestion, but also reduced fibre digestion and milk fat concentration. These observations suggest a greater effect of forage type on lactation performance than concentrate type per se under the conditions of the current study.

Analysis of Milk from Different Sources Based on Light Propagation and Random Laser Properties

Milk is a valuable contributor to a healthy diet as it contains nutritional components such as fats, proteins, carbohydrates, calcium, phosphorous and vitamins. This research aimed to differentiate milk from animal, plant and human sources based on light propagation and random-laser properties. Experimental, statistical and theoretical analyses were used. Light propagation in different types of milk such as almond milk, oat milk, soy milk, fresh milk, goat milk and human breast milk was measured using the spectrometry method. Near-IR and visible light transmission through the diluted milk samples were compared. Soy milk and fresh milk have the highest absorbance and fluorescence of light, respectively, due to a high content of fat, protein and carbohydrates. Principal component analysis was used to determine the accuracy of the experimental results. The research method is comprehensive as it covers light propagation from 350 nm to 1650 nm of wavelength range and non-intrusive as it does not affect the sample. Meanwhile, analysis of milk was also conducted based on random-laser properties such as multiple emission peaks and lasing threshold. Higher fat content in milk produces a lower random lasing threshold. Thus, we found that milk from animals, plants and humans can be analyzed using light absorption, fluorescence and random lasers. The research method might be useful for future study of milk contaminants that change the properties of milk.

325 The Diagnosis of Sub-acute Ruminal Acidosis (SARA) in Dairy Cows on Commercial Farms Using the Milk Fatty Acid Profile

Abstract The accuracy of the milk fatty acid profile as a diagnostic tool for the diagnosis of sub-acute ruminal acidosis (SARA) has been determined when SARA was experimentally induced. This had not yet been done not on commercial dairy farms, where SARA can occur naturally. The objective of this study was to determine this accuracy in individual cows on commercial dairy farms. A total of 336 cows from 24 commercial dairy farms in Quebec were included. Farms were blocked based on geographical location and management, with each block having one high risk SARA farm and one low risk SARA farm. Farm Risk of SARA was determined based on the milk fat content and the proportions of de novo fatty acids and long chain unsaturated fatty acids in the bulk tank. On each farm, 7 early/mid-lactation (&amp;lt; 150 days in milk DIM) and 7 mid/late lactation (&amp;lt; 150 DIM) cows were randomly selected. The fatty acid profile of pooled milk samples from these cows were determined by gas chromatography. Farm risk of SARA did not affect the milk fat proportion of fatty acids, with the exception of trans 10 cis 12 C18:2, which was higher in At Risk Farms. Later lactation cows had a higher milk fat content and higher milk fat proportions of de novo, C16 fatty, and odd and branch chain fatty acids. The prevalence of SARA was likely higher in earlier lactation cows than in later lactation cows, but non-SARA related animal and dietary factors also affect the milk fatty acid profile. Hence, the milk fatty acid profile alone may not be accurate enough to diagnose SARA on farm. This profile can, however, contribute to this diagnosis, the identification of causes of milk fat depression, and the development of strategies to optimize the milk fatty acid profile.

PSXIV-15 The effects of body condition score on the milk production and energy balance of transition dairy cows

Abstract Our objective was to evaluate the effects of body condition score (BCS) on the milk production and energy balance of transition dairy cows. Seventy-five multiparous dairy cows were separated into four groups according to the BCS, HH (4.25 ± 0.23 and 3.35 ± 0.19 BCS, pre and postpartum, respectively, n = 17), HM (4.14 ± 0.15 and 2.92 ± 0.24, n = 19), MM (3.10 ± 0.21 and 2.78 ± 0.17, n = 23), ML (2.88 ± 0.23 and 2.46 ± 0.19, n = 16). The milk yield, rumen pH, etc., data were collected and analyzed using a one-way ANOVA model in SAS (SAS version 9.4, SAS Institute Inc., Cary, NC, USA). The ML group had a higher milk yield and total solid yield than the MM group (P &amp;lt; 0.05), while the HH and HM groups had no difference with other groups. The HM and ML groups had a higher milk fat content than the MM group (P &amp;lt; 0.05), while the HH group had no difference with other groups. Milk protein content in the HH group was higher than the ML group (P &amp;lt; 0.05). The milk lactose, total solids, urea content in these groups had no difference. The ML group had a higher milk acetone content than the HH group (P &amp;lt; 0.05). The BCS change in the HH and HM groups was higher than the MM and ML groups, and that in the ML group was higher than the MM group (P &amp;lt; 0.05). The rumen pH had no difference within these groups. These findings collectively indicated the prepartum dairy cow with middle BCS would have a more efficient body fat utilization and a better milk production performance. Furthermore, reducing body fat loss is necessary to avoid the negative energy balance.

Improving dairy performance through molecular characterization of SREBP-1 gene in Sarda sheep breed

This research has two aims: (i) to characterize the coding sequence of the SREBP-1 gene in dairy sheep in order to investigate possible relationships between single nucleotide polymorphisms (SNPs) and milk traits; and (ii) to investigate possible relationship between SREBP-1 gene expression and nucleotide variation. Four hundred adult and multiparous lactating Sarda breed ewes were selected from two farms. Milk samples were collected from Day 30 to Day 150 of lactation to determine the mean yield, somatic cell count, lactose, fat, and protein content of the milk. RNA was extracted from the milk samples, after which the SREBP-1 gene coding regions were amplified and sequenced to scan mutations. Whilst eight SNPs were identified, none had statistically significant association with the analysed milk traits. Moreover, the identified expression patterns were not affected by the SNP or combined genotypes. High SREBP-1 gene expression levels were found to be correlated with high milk fat content (P < 0.01), indicating the crucial role of this gene in the milk fat synthesis. In conclusion, the polymorphisms found within SREBP-1 gene exhibited no significant associations with milk traits or with individual SREBP-1 mRNA expression patterns. The findings thus suggest that this small genetic variability may derive from the selection carried out in Sarda breed to improve milk yield.

STUDY OF β-CASEIN GENE POLYMORPHISM AND ITS RELATIONSHIP WITH MILK COMPOSITION OF UKRAINIAN BLACK-AND-WHITE DAIRY COWS

In the breeding herds of the Ukrainian Black-and-White Dairy breed, the research was conducted to study the polymorphism of β-casein gene and its effect on the qualitative composition of cow's milk. Genotyping of 146 heads of cattle was carried out. Determination of β-casein gene polymorphism was performed in the genetic laboratory of Bohomolets Institute of Physiology. The TagMan@Genotyping system and a set of primers and probes were used for allelic discrimination. It was found that the frequencies of alleles A1 (0.421) and A2 (0.579) in the locus of β-casein gene were different, the latter being higher. Consequently, the frequencies of genotypes A1A1, A1A2 and A2A2 were different, 25%, 35% and 40% respectively. According to genetic and statistical analysis, there was an excess of homozygous variants of A1A1 and A2A2 in the β-casein locus, and a lack of heterozygous A1A2. There was a difference in the quality characteristics of milk between animals of different genotypes. The content of individual milk constituents did not vary equally depending on the β-casein genotype, but this difference was statistically insignificant. The average content of constituents in the milk of cows corresponded to the breed standards in terms of fat content and was slightly inferior to it in terms of protein content. Cows of Ukrainian Black-and-White Dairy breed with heterozygous A1A2 genotype exceeded others in terms of protein, lactose and dried skimmed milk remainder. Homozygous genotypes A1A1 and A2A2 had higher fat content in milk than heterozygotes. As there is no statistically significant difference in the main milk constituents (fat, protein) between animals of different genotypes for β-casein, the formation of herds with A2A2 genotype for β-casein will not adversely affect the productive traits of cows and thus ensure sufficient quality indicators of milk of new herd types. Livestock breeders need to pay some attention to selection and technological measures to increase the protein content in milk.

Anti-freeze effect of Enoki mushroom extract on the quality preservation of frozen whipped cream

The alkaline extract of Enoki mushroom (Flammulina velutipes) has been shown to have ice crystal growth inhibiting activity, and its beneficial effect on the quality preservation of frozen foods is highly expected. The purpose of this study was to investigate the effect of Enoki mushroom extract which has an ice recrystallization inhibiting activity on the quality of frozen whipped creams. Whipping creams with different milk/vegetable fat compositions were prepared. The proportion of % milk fat and % vegetable fat was given as follows; 0:37, 10:28, 20:20 and 40:0, respectively. Whipped foam samples were frozen and stored at −20 °C, then the effect of adding 0.1% Enoki mushroom extract was tested. Fresh dairy flavor and smooth melt in mouth texture was deteriorated during the course of frozen storage for 37 days, and the frequency is higher in whipped creams with high milk fat content. Addition of 0.1% Enoki mushroom extract ameliorated these quality changes and significantly retained moisture content. Microscopic observation of the internal structure of frozen foam samples by cryo-SEM revealed that the ice crystal aggregates grown in the emulsified solid phase were reduced by adding Enoki mushroom extract. GC/MS analysis of the flavor components revealed that the content of furan compounds (furfural and 2-furanmethanol) was increased by 1.7 times in control foam samples during frozen storage, whereas the furan compounds in whipped foam sample containing Enoki mushroom extract did not increase after frozen storage. Based on these findings, it is proposed that ice crystal growth at the emulsified solid phase causes the sublimation of water on the surface of frozen whipped cream and destruction of the network structure of fat globules results in the quality changes after thawing. Enoki mushroom extract was found to retard ice crystal growth in whipped cream, thus supposed to reduce the quality changes during frozen storage.