Methanogenic Population and CH4 Production in Swedish Dairy Cows Fed Different Levels of Forage

Methanogenic community structure, methane production (CH(4)), and volatile fatty acid (VFA) profiles were investigated in Swedish dairy cows fed a diet with a forage/concentrate ratio of 500/500 or 900/100 g/kg of dry matter (DM) of total DM intake (DMI). The rumen methanogenic population was evaluated using terminal restriction fragment length polymorphism (T-RFLP) analysis, 16S rRNA gene libraries, and quantitative real-time PCR (qRT-PCR). Mean CH(4) yields did not differ (P > 0.05) between diets, being 16.9 and 20.2 g/kg DMI for the 500/500 and 900/100 diets, respectively. The T-RFLP analysis revealed that populations differed between individual cows and that each individual population responded differently to the diets. The 16S rRNA gene libraries revealed that Methanobrevibacter spp. dominated for both diets. CH(4) production was positively correlated with a dominance of sequences representing T-RFs related to Methanobrevibacter thaueri, Methanobrevibacter millerae, and Methanobrevibacter smithii relative to Methanobrevibacter ruminantium and Methanobrevibacter olleyae. Total numbers of methanogens and total numbers of Methanobacteriales were significantly higher with the 500/500 diet (P < 0.0004 and P < 0.002, respectively). However, no relationship was found between CH(4) production and total number of methanogens. No differences were seen in total VFA, propionic acid, or acetic acid contents, but the molar proportion of butyric acid in the rumen was higher for the 500/500 diet than for the 900/100 diet (P < 0.05). Interestingly, the results also revealed that a division of the identified methanogenic species into two groups, suggested in the work of King et al. (E. E. King, R. P. Smith, B. St-Pierre, and A. D. G. Wright, Appl. Environ. Microbiol. 77:5682-5687, 2011), increased the understanding of the variation in CH(4) production between different cows.     

Incidence of Mycobacterium paratuberculosis in Bulk Raw and Commercially Pasteurized Cows' Milk from Approved Dairy Processing Establishments in the United Kingdom

Over a 17-month period (March 1999 to July 2000), a total of 814 cows' milk samples, 244 bulk raw and 567 commercially pasteurized (228 whole, 179 semiskim, and 160 skim), from 241 approved dairy processing establishments throughout the United Kingdom were tested for the presence of Mycobacterium paratuberculosis by immunomagnetic PCR (to detect all cells living and dead) and culture (to detect viable cells). Overall, M. paratuberculosis DNA was detected by immunomagnetic PCR in 19 (7.8%; 95% confidence interval, 4.3 to 10.8%) and 67 (11.8%; 95% confidence interval, 9.0 to 14.2%) of the raw and pasteurized milk samples, respectively. Confirmed M. paratuberculosis isolates were cultured from 4 (1.6%; 95% confidence interval, 0.04 to 3.1%) and 10 (1.8%; 95% confidence interval, 0.7 to 2.8%) of the raw and pasteurized milk samples, respectively, following chemical decontamination with 0.75% (wt/vol) cetylpyridinium chloride for 5 h. The 10 culture-positive pasteurized milk samples were from just 8 (3.3%) of the 241 dairy processing establishments that participated in the survey. Seven of the culture-positive pasteurized milk samples had been heat treated at 72 to 74°C for 15 s; the remainder had been treated at 72 to 75°C for the extended holding time of 25 s. When typed by restriction fragment length polymorphism and pulsed-field gel electrophoresis methods, some of the milk isolates were shown to be types distinct from those of laboratory strains in regular use within the testing laboratory. From information gathered at the time of milk sample collection, all indications were that pasteurization had been carried out effectively at all of the culture-positive dairies. That is, pasteurization time and temperature conditions complied with the legal minimum high-temperature, short-time process; all pasteurized milk samples tested phosphatase negative; and postprocess contamination was considered unlikely to have occurred. It was concluded that viable M. paratuberculosis is occasionally present at low levels in commercially pasteurized cows' milk in the United Kingdom.     

Ketosis Treatment and Milk Yield in Dairy Cows Related to Milk Acetoacetate Levels

Milk yield and milk acetoacetate (M-acac) were measured weekly for the first 6 weeks of lactation in 5 herds with a ketosis problem. Ketosis treatments and the corresponding ketotest score, were also recorded. The treatment rate was highest 7–16 days after calving. Most of these early cases were associated with low ketone levels in milk, whereas the treatment ratefor cows with high ketone levels was highest 17–31 days after calving. Nearly half of the treated cows were low-ketone animals. They were classified as ketosis cases in the cow health card records, although probably suffering from other post partum disturbances in many instances. About 40 % of the cows with high ketone levels recovered spontaneously. Reduction in milk yield associated with peak M-acac levels was transient and moderate. It was concluded that health card statistics overestimates the severity of the ketosis problem in Norway.     

Differential Cell Counting in Fraction-Collected Milk from Dairy Cows

Cell con-centrations and cell populations were studied in fraction-collected milk by use of cytofluorometric methods. The results indicate differences in the condition of udders producing milk with more and less than 100 000 cells per ml, respectively     

Repeated Isolation of Yersinia enterocolitica from Pasteurized Milk in a Holding Vat at a Dairy Factory

Yersinia enterocolitica biotype 1 serotype 5a was repeatedly isolated from pasteurized milk in the same holding vat at a particular dairy factory. It is considered that the occurrence of this organism in pasteurized milk may be partially attributed to its ability to multiply at refrigeration temperatures and survive in inadequately 'disinfected' vats.     

Effect of Zinc Methionine or Zinc Sulfate Supplementation on Milk Production and Composition of Milk in Lactating Dairy Cows

Eighteen lactating dairy cows were used to compare the effects of organic and inorganic Zn supplements on milk production and chemical composition of milk. Animals received three diets in a randomized block design: basal diet with no supplemental Zn (control, 42 mg Zn/kg), basal diet plus 500 mg Zn/kg of dry matter (DM) as zinc sulfate monohydrate (ZnS) and basal diet plus 500 mg Zn/kg of DM as zinc methionine (ZnM). Results showed that milk and fat-corrected milk yield in dairy cows were not significantly affected by Zn source although a numerical increase was observed. The percentages of protein, lactose, fat, solid nonfat, total solid, and density of milk were not significantly different between treatments. However, dairy cows that received ZnM tended to produce more milk and fat-corrected milk with a lower somatic cell count as compared to controls. The zinc concentration in milk in the ZnM and ZnS groups was higher (P < 0.05) than in milk from the control group, but there were no significant differences between ZnS and ZnM groups.     

Choline and Choline Metabolite Patterns and Associations in Blood and Milk during Lactation in Dairy Cows

Milk and dairy products are an important source of choline, a nutrient essential for human health. Infant formula derived from bovine milk contains a number of metabolic forms of choline, all contribute to the growth and development of the newborn. At present, little is known about the factors that influence the concentrations of choline metabolites in milk. The objectives of this study were to characterize and then evaluate associations for choline and its metabolites in blood and milk through the first 37 weeks of lactation in the dairy cow. Milk and blood samples from twelve Holstein cows were collected in early, mid and late lactation and analyzed for acetylcholine, free choline, betaine, glycerophosphocholine, lysophosphatidylcholine, phosphatidylcholine, phosphocholine and sphingomyelin using hydrophilic interaction liquid chromatography-tandem mass spectrometry, and quantified using stable isotope-labeled internal standards. Total choline concentration in plasma, which was almost entirely phosphatidylcholine, increased 10-times from early to late lactation (1305 to 13,535 µmol/L). In milk, phosphocholine was the main metabolite in early lactation (492 µmol/L), which is a similar concentration to that found in human milk, however, phosphocholine concentration decreased exponentially through lactation to 43 µmol/L in late lactation. In contrast, phosphatidylcholine was the main metabolite in mid and late lactation (188 µmol/L and 659 µmol/L, respectively), with the increase through lactation positively correlated with phosphatidylcholine in plasma (R ² = 0.78). Unlike previously reported with human milk we found no correlation between plasma free choline concentration and milk choline metabolites. The changes in pattern of phosphocholine and phosphatidylcholine in milk through lactation observed in the bovine suggests that it is possible to manufacture infant formula that more closely matches these metabolites profile in human milk.     

Comparison of Effects of Potassium Iodide and Iodosalicylates on the Antioxidant Potential and Iodine Accumulation in Young Tomato Plants

Iodine (I) is classified as a beneficial element for plants. Until now, there have been only hypotheses regarding the uptakes of organic iodine compounds by plant roots. The purpose of our research was to compare the uptakes and effects of the application of the following mineral and organic iodine compounds on young tomato plants: KI, 5-iodosalicylic (5-ISA), and 3,5-diiodosalicylic (3,5-diISA) acids. An additional control combination included the treatment with salicylic acid (SA) alone. All compounds were introduced into the nutrient solution in 5, 10, 25, and 50 μM I concentrations. It was established that after the application of 5-ISA and 3,5-diISA, iodine is taken up to a smaller extent than from KI. The tested KI, 3,5-diISA, and 5-ISA doses had no negative impact on the growth and development of plants, apart from the reduction of shoot biomass after the application of 3,5-diISA in 10 and 25 µM I doses. All applied compounds, except for SA, caused a reduction of ascorbic acid (AA) content and increase of dehydroascorbic acid (DHA) content in leaves. A significant increase of APX activity was noted only for the highest doses of KI and 5-ISA. None of the iodine compounds, in most tested doses, have substantially increased the CAT and POX activities in tomato leaves. Application of KI decreased the levels of all analyzed sugars in tomato leaves. The effect of iodosalicylates on sugar content varied depending on the compound: when applied in the highest dose 5-ISA increased, while 3,5-diISA decreased the sugar accumulation in tomato plants. In all tested treatments, a reduction of SA content in leaves was noted. We conclude that organic iodine compounds, i.e., 3,5-diISA and 5-ISA, can be taken up by the roots of tomato plants at an early stage of development.

     

Unexpected Decrease in Milk Production after Fenbendazole Treatment of Dairy Cows during Early Grazing Season

Gastrointestinal nematodes (GIN) infection can impair milk production (MP) in dairy cows. To investigate whether MP would be optimized by spring targeted-selective anthelmintic treatment in grazing cows, we assessed (1) the effect on MP of an anthelmintic treatment applied 1.5 to 2 months after turn-out, and (2) herd and individual indicators associated with the post-treatment MP response. A randomized controlled clinical trial was conducted in 13 dairy farms (578 cows) in western France in spring 2012. In each herd, lactating cows of the treatment group received fenbendazole orally, control cows remained untreated. Daily cow MP was recorded from 2 weeks before until 15 weeks after treatment. Individual serum pepsinogen and anti-Ostertagia antibody levels (expressed as ODR), faecal egg count and bulk tank milk (BTM) Ostertagia ODR were measured at treatment time. Anthelmintic treatment applied during the previous housing period was recorded for each cow. In each herd, information regarding heifers’ grazing and anthelmintic treatment history was collected to assess the Time of Effective Contact (TEC, in months) with GIN infective larvae before the first calving. The effect of treatment on weekly MP averages and its relationships with herd and individual indicators were studied using linear mixed models with two nested random effects (cow within herd). Unexpectedly, spring treatment had a significant detrimental effect on MP (-0.92 kg/cow/day on average). This negative MP response was particularly marked in high producing cows, in cows not treated during the previous housing period or with high pepsinogen levels, and in cows from herds with a high TEC or a high BTM ODR. This post-treatment decrease in MP may be associated with immuno-inflammatory mechanisms. Until further studies can assess whether this unexpected result can be generalized, non-persistent treatment of immunized adult dairy cows against GIN should not be recommended in early grazing season.