Lipid composition of bovine teat canal keratin

Keratin was obtained by scraping the teat canals of excised teats from 12 lactating and 12 dry cows immediately after slaughter. Teats from four lactating and four dry cows were also stored at -20 degrees C for 2 wk to assess whether keratin composition was affected by frozen storage. Lipids were extracted from keratin of individual teats with 2:1 chloroform-methanol. Neutral lipid classes were determined by TLC and fatty acids by capillary GLC. Total lipid content of keratin was 4% of wet weight. Lipid composition of keratin from fresh and frozen teats was similar. Differences were observed in several lipid classes between keratin from lactating and dry cows. Triglycerides were higher in keratin from lactating cows, 58.4 vs. 28.1%, whereas cholesterol was lower in keratin from lactating cows, 18.5 vs. 37.5%. Short-chain and medium-chain fatty acids were 3x lower in keratin from dry than from lactating cows; 18:2 and polyunsaturated fatty acids were 2x higher in keratin from dry than from lactating cows. Results indicated that large differences exist between the detailed lipid composition of keratin from dry and lactating dairy cows.     

Effect of clinical and subclinical mastitis on lipid composition of teat canal keratin.

Two experiments were conducted to investigate lipid composition of teat canal keratin when different conditions of bacterial colonization and quarter inflammation were present. In Experiment 1, 11 multiparous cows with subclinical mastitis (bacteria present but no visible inflammation) in at least one quarter were selected for study. Quarters that were sampled and found negative for bacterial growth were classified as control. In Experiment 2, 10 multiparous cows with clinical mastitis in one or more quarters were selected. Milk samples from inflamed quarters were cultured to identify mastitis pathogens; these quarters were classified as clinical; all other quarters were classified as control. Teat canal keratin was collected from all quarters just before an a.m. milking, samples were weighed, and lipid determinations were conducted by TLC. Keratin from subclinical quarters compared with keratin from control quarters did not differ in either neutral lipid or fatty acid composition. Total lipid was significantly higher in keratin from teats of clinical quarters than in keratin from control quarters (27.8 vs. 21.5 microgram/mg). Neutral lipid composition of keratin was similar between teats from clinical quarters and teats from control quarters. In Experiment 2, quarter foremilk samples were also obtained to determine lipid composition. The FFA in milk from clinical quarters contained fewer short-chain fatty acids, whereas polyunsaturated fatty acids were significantly higher in milk from clinical quarters.     

Methods of collection and lipid composition of teat canal keratin in dry and lactating cows.

Methods for collecting keratin from the teat canal were examined to select a procedure to obtain representative samples for lipid analysis. Data obtained by solvent extraction of excised teats were compared with those obtained by scraping keratin from dissected teats of lactating and dry cows. Solvent extraction with petroleum ether or 2:1 chloroform-methanol yielded similar dry weights of material. However, both solvents removed large amounts of material other than keratin from the teat canal. The lipid class and fatty acid profiles of the material extracted by solvent flushing were not similar to profiles obtained by scraping keratin from the teat canal. A metal tapestry needle was suitable for collection of keratin from the teat canal of living cows. About 78% of the keratin present in the teat was collected with the needle. Lipid composition of keratin collected with the needle was the same as in keratin scraped from excised teats. The tapestry needle was suitable as a tool for collecting repeatable, representative samples of keratin for analysis from single teat canals of living cows.     

Closing forces of the bovine teat canal

The magnitude of the forces causing closure of the bovine teat canal was estimated by measuring the pressure required to cause retrograde flow of milk into the canal from a manometer attached to the external teat orifice. Before milking, the hydrostatic pressure required to cause retrograde flow was 12 kPa or greater. Retrograde flow occurred at a pressure of 4-6 kPa once the teat canal surface had been wetted. This 2- or 3-fold fall in the closing forces presumably resulted from the combined effects of fracturing the teat canal epithelium and loss of initial resting tension in the smooth muscle fibres surrounding the teat canal. After milking, retrograde flow into any teat canal occurred at a pressure approximately 1 kPa lower than the wetted, pre-milking value. This small drop, and subsequent recovery approximately 30 min after milking, reflects the change in tonicity of the smooth muscle fibres which are stretched during milking. At hydrostatic pressures below 7-9 kPa, retrograde flow could be arrested momentarily by the occurrence of a teat contraction. At 4-7 kPa, the wave of contraction was also capable of expelling 4-14 microliters milk from the teat canal indicating the outwardly directed, peristaltic nature of the phasic muscular activity.     

Regeneration of teat canal keratin in lactating dairy cows.

This study was designed to determine the regeneration rate of teat canal keratin in two groups of 10 lactating Holstein cows. The weight of keratin obtained upon successive collections of keratin was determined. Intervals between successive collections were varied between 8 and 72 h. Following initial collection, the quantity of keratin removed was regenerated within 1 to 2.5 d. The rate of keratin regeneration per teat was approximately 1.5 mg of wet weight or .6 mg of dry weight per 24 h. The concentration (microgram lipid/mg keratin, wet weight) of lipid in keratin samples collected during regeneration was almost twice that present initially or after regeneration was complete. With the exception of free cholesterol, composition (%) of lipid components of keratin did not differ between samples collected initially, those collected early in the process of regeneration, and those collected after the mass of keratin removed had been replaced. Although data suggest that keratin matures during the process of regeneration, maturation appears complete by the time mass of keratin is fully regenerated. Additionally, the quantity of keratin recovered at initial sampling was inversely correlated with milk production. We hypothesize that as milk production increases, more keratin is lost during milking.     

Effects of teatcup liner tension on teat canal keratin and teat condition in cows

The effect of tension of teatcup liners on teat end condition and quantity of keratin in the teat canal was investigated. Liner tension was increased by using longer teatcup shells. The first experiment used six Holstein cows in early lactation. Left quarters were milked with liners under medium or normal tension by using Conewango liners in 142 mm shells. Right quarters were milked with liners under high tension by mounting the liners in teatcup shells 149 mm in length. By day 16 teat end condition and sensitivity to manipulation were worsened by thrice daily milking when liners were under a higher tension. Two subsequent experiments each used 12 different Holstein cows. These cows were in mid lactation and were milked twice daily for 10 or 30 d. Left quarters were milked with liners under high tension Right quarters were milked with liners under low tension by using teatcup shells 126 mm in length. The quantity of keratin removed during milking was not influenced by liner tension: however, the quantity of keratin at the end of the experiments was increased 10-20% in teats that were milked using liners under higher tension. Histological analysis and keratin content were consistent with epithelial hyperplasia induced by milking with liners under increased tension.     

Lipid composition of teat canal keratin collected before and after milking from Holstein and Jersey cows.

In three experiments, keratin was collected from individual teats of 40 Holstein and 20 Jersey cows immediately before and after milking. In Experiments 1 and 2, keratin collected from teats of 20 Holstein cows before milking was compared with keratin collected after milking. In Experiment 3, keratin was collected from two teats of 20 Jersey and 20 Holstein cows before milking and compared to the other two teats of the same cows after milking. All three experiments yielded similar results. In Holsteins, keratin weight before milking was 1.6 times greater than keratin weight after milking (3.1 vs. 1.9 mg). In Jerseys, only small amounts of keratin were removed during milking (3.5 mg before vs. 3.1 mg after) In Holsteins and Jerseys, neutral lipid concentration was 1.6 times greater after milking than before, suggesting that when keratin was removed during milking, only moderate amounts of lipid were removed. In Holsteins, total lipid collected per teat was similar before or after milking (59.2 vs. 48.5 micrograms). Results demonstrate that keratin collected after milking had a different lipid composition than keratin collected before milking.     

Increased susceptibility to intramammary infection following removal of teat canal keratin.

Influence of teat canal keratin on susceptibility to intramammary infection was investigated in lactating Jersey cows. In each of two replicate trials, keratin was removed from the left teats of 20 cows immediately before milking. Immediately after milking, all teats were exposed to bacterial challenge by immersion in a suspension of Streptococcus agalactiae (5 x 10(7) cfu/ml). Bacterial challenge was repeated after the next four milkings. Foremilk samples were obtained for 8 d after keratin removal to determine infection status. A mammary quarter was classified as infected based solely upon the bacteriological criteria outlined by the National Mastitis Council. The rate of infection in quarters from which keratin was removed was greater than that in control quarters. Infection rates were 26.3% for keratin-removed quarters and 8.3% for control quarters in trial 1 and 13.5 and 0%, respectively, in trial 2. When more stringent criteria (recovery of greater than 100 cfu of S. agalactiae/ml in three or more successive milk samples and a SCC of greater than 10(6)) were used to identify a subset of infections that were clearly intramammary, infection rates were 9.3% for keratin-removed quarters and 1.4% for control quarters. Thus, partial removal of keratin from the teat canal compromised the ability of the teat to prevent passage of bacterial pathogens from the external environment into the mammary gland.     

The bovine teat canal: information from measurement of velocity of milk flow from the teat

The velocity of milk flow from the teat during the peak flow rate period of milking was estimated to be approximately 8.5 m/s with a liner vacuum of 50 kPa and 7.5 m/s at 40 kPa. These results confirm the applicability of the Bernoulli theorem for estimating velocity of milk flow through the teat canal during milking. Concurrent measurements of mass flow rate and velocity indicate that the effective diameter of the open teat canal is approximately 2 mm. Further calculations indicate that the shear force due to milk flow acting to debride the surface of the open teat canal is about 1.8 X 10(-2) N. The opposing surfaces of the 'closed' teat canal may be approximately 100 micron apart immediately after milking. If so, bacteria present in the milk residue within the teat canal would never be more than 50 micron from a surface.     

Effects of a 1.94% sulfonic acid teat dip and a 1% iodophor teat dip on teat canal infections in lactating dairy cows

Sixty-three cows were used in a natural exposure trial for 1 yr to determine the effects of a 1.94% linear dodecyl benzene sulfonic acid and a 1% iodophor teat dip on teat canal and intramammary infections. Overall, total teat canal infections increased 28.9% and total intramammary infections increased 30% in quarters dipped with the linear dodecyl benzene sulfonic acid compared with a 14.3% increase in teat canal infections and a 17.4% decrease in intramammary infections for the iodophor group. Higher frequencies were observed for teat canal and intramammary infections caused by Staphylococcus epidermidis in the linear dodecyl benzene sulfonic acid group. Staphylococcus hyicus was the predominant organism isolated from teat canal and intramammary infections in the iodophor group. No difference was observed between the two teat dips in the persistence of Staphylococcus aureus teat canal infections. A greater number of S. hyicus teat canal infections persisted in the iodophor group, whereas teat canal infections produced by S. epidermidis and Staphylococcus xylosus persisted longer in the sulfonic acid group. Results of this study indicated that use of a linear dodecyl benzene sulfonic acid teat dip for 1 yr was not associated with increased S. aureus teat canal infections and intramammary infections. However, linear dodecyl benzene sulfonic acid appeared to affect the distribution of coagulase-negative staphylococci isolated from teat canal infections and intramammary infections.     

Fatty acid composition of trout oil

Fatty acid analysis of oils from farmed trout of the species Oncorhynchus mykiss was carried out by gas-liquid chromatography with a flame ionisation detector (FID). Results show an influence of trout age and sex in fatty acid composition of the oils analysed. Trout oil has more docosahexaenoic acid (DHA) than eicosapentaenoic acid (EPA) and, while the EPA content does not change during growth, DHA diminishes during trout development, especially in females. In the group of medium sized trout (140–200 g), the ratios of SFA:MUFA:PUFA are similar to those recommended by the American Heart Association.     

Effect of postmilking teat antisepsis on teat canal infections in lactating dairy cows

Effects of a .18% iodophor teat dip and a fatty acid plus lactic acid teat dip on teat canal infections were studied in two separate trials under experimental challenge procedures using Staphylococcus aureus and Streptococcus agalactiae. The iodophor teat dip was 90% effective in preventing new S. aureus teat canal infections and 95.6% effective in reducing progression of S. aureus teat canal infections to intramammary infections. The dip also reduced persistence of S. aureus teat canal colonizations from week to week by 94.4%. The fatty acid plus lactic acid dip had no effect on preventing S. aureus teat canal infections but reduced progression of S. aureus teat canal infections to intramammary infections by 43.8%. The fatty acid plus lactic acid dip also reduced the persistence of S. aureus teat canal infections by 39%. An insufficient number of Strep. agalactiae teat canal infections was detected in both trials for valid analyses. Neither dip had any effect on prevalence of naturally occurring, coagulase-negative staphylococcal teat canal infections or on teat canal infections by other organisms.     

Fatty acid composition of Camellia oleifera oil

Camellia oleifera originates from China and is important for the economy of southern China. Seeds from the cultivars LCDG, YAYC, and CR3 of Camellia oleifera were analyzed for their amount of 14 different fatty acids (unsaturated, monounsaturated, polyunsaturated, and saturated). In contrast to former investigations additional kinds of fatty acids could be isolated from Camellia oleifera seeds: The composition of this oil is very similar to olive oil, comprising 67.7?C76.7?% oleic acid, 82?C84?% unsaturated fatty acids, 68?C77?% monounsaturated fatty acids, and 7?C14?% polyunsaturated acids. Moreover, Camellia oleifera oil has many advantages to rapeseed oil, peanut oil, soybean oil, safflower seed oil, and especially pig oil.     

澳洲坚果油脂肪酸组成分析

采用气相色谱-质谱联用技术对澳洲坚果油中的脂肪酸组成进行分析.结果表明,澳洲坚果油有10种脂肪酸,主要有棕榈油酸、油酸和11-二十烯酸等不饱和脂肪酸(相对含量77.23%)以及月桂酸、肉豆蔻酸、棕榈酸、硬脂酸、花生酸等饱和脂肪酸(相对含量22.39%),其中油酸相对含量达58.60%.     

Fatty acid composition of rice oils.

Analysis of rice oil methyl esters of two varieties by gas-liquid chromatography showed that oil from bran-polish and oil from milled rice extracted with petroleum ether had similar fatty acid composition and had oleic/linoleic acid ratios of about 1.0. However, milled rice oil extracted with chloroform/methanol had a higher linoleic acid content and a lower oleic acid content than oil extracted with petroleum ether.     

Fatty acid composition of the lipids of whitefish

The fatty-acid composition of lipids was studied in the muscular tissue and internal organs of whitefish living in Siberian rivers, that had been moved to lakes where it had not lived before. Changes in the lipid composition were recorded in mature fish moved into the lakes and in this year's brood. It was found that lipids of mature fish were resistant to oxidizing damage.     

几种风吹楠属植物脂肪酸成分分析

采用索氏提取法对滇南风吹楠、风吹楠和琴叶风吹楠3种风吹楠属植物的油脂含量进行测定,并将油脂样品进行甲酯化处理后,利用气相色谱-质谱联用技术(GC-MS)对其脂肪酸组成及相对含量进行分析。结果表明:3种植物的种仁含油率都在54%以上,属于高含油植物;总脂肪酸中二十碳以下的脂肪酸含量都在99%以上,是比较理想的生物柴油的原料。     

Fatty acid composition of Hibiscus ficulneus seed oil

The fatty acid composition of seed oil from Hibiscus ficulneus (Malvaceae) was analysed by thin-layer and gas-liquid chromatography. In addition to normal saturated and unsaturated fatty acids, three hydrogen bromide-reactive fatty acids were also identified. These were shown to be epoxyoleic (4.9%), malvalic (4.2%), and sterculic (1.0%) acids. Seed oils of Vernonia anthelmintica and Sterculia foetida were used as reference standards.     

Investigating the cow skin and teat canal microbiomes of the bovine udder using different sampling and sequencing approaches

There is a need for standardized, efficient, and practical sampling methods to support large population-based studies of the internal and external epithelial microbiomes of the bovine udder. The primary objective of this study was to evaluate different sampling devices for the isolation of microbial DNA originating from the internal and external teat epithelium. Secondary objectives were to survey and compare the microbial diversity of external and teat canal epithelial microbiomes using amplicon and shotgun metagenomic sequencing approaches. To address these objectives, we enrolled a convenience sample of 24 Holstein dairy cows and collected samples from the external epithelium at the base of udder, the external teat barrel epithelium, the external teat apex epithelium, and the teat canal epithelium. Extracted DNA was quantified and subjected to PCR amplification of the V4 hypervariable region of the 16S rRNA gene and sequenced on the Illumina MiSeq platform (Illumina Inc., San Diego, CA). A subset of samples was subjected to a shallow shotgun metagenomic assay on the Illumina HiSeq platform. For samples collected from the external teat epithelium, we found that gauze squares consistently yielded more DNA than swabs, and Simpson's reciprocal index of diversity was higher for gauze than for swabs. The teat canal epithelial samples exhibited significantly lower diversity than the external sampling locations, but there were no significant differences in diversity between teat apex, teat barrel, and base of the udder samples. There were, however, differences in the microbial distribution and abundances of specific bacteria across external epithelial surfaces. The proportion of shotgun sequence reads classified as Bos taurus was highly variable between sampling locations, ranging from 0.33% in teat apex samples to 99.91% in teat canal samples. These results indicate that gauze squares should be considered for studying the microbiome of the external epithelium of the bovine udder, particularly if DNA yield must be maximized. Further, the relative proportion of host to non-host DNA present in samples collected from the internal and external teat epithelium should be considered when designing studies that utilize shotgun metagenomic sequencing.