Lamellar arrangements of linear polyethylene in ultrathin films

The crystal orientations of linear polyethylene films on silicon substrates are investigated using grazing incidence X‐ray diffraction and atomic force microscopy. From diffraction analysis, we can identify the structural arrangement of PE crystals in ultrathin film. The orientation of lamellar crystal in PE films changes from edge‐on to flat‐on with the decrease of film thickness in the film thickness below ～ 100 nm. The slightly inclined lamellae relative to the substrate are found to coexist with the flat‐on lamellae in thin PE films that we have investigated. We find that the crystal orientation and structures is governed by the constraint imposed by film thickness rather than enthalpy gain as the film got thinner especially in the thickness below 200 nm. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

The Role of Exosomal Epigenetic Modifiers in Cell Communication and Fertility of Dairy Cows

Abnormal uterine function affects conception rate and embryo development, thereby leading to poor fertility and reproduction failure. Exosomes are a nanosized subclass of extracellular vesicles (EV) that have important functions as intercellular communicators. They contain and carry transferable bioactive substances including micro RNA (miRNA) for target cells. Elements of the cargo can provide epigenetic modifications of the recipient cells and may have crucial roles in mechanisms of reproduction. The dairy industry accounts for a substantial portion of the economy of many agricultural countries. Exosomes can enhance the expression of inflammatory mediators in the endometrium, which contribute to various inflammatory diseases in transition dairy cows. This results in reduced fertility which leads to reduced milk production and increased cow maintenance costs. Thus, gaining a clear knowledge of exosomal epigenetic modifiers is critical to improving the breeding success and profitability of dairy farms. This review provides a brief overview of how exosomal miRNA contributes to inflammatory diseases and hence to poor fertility, particularly in dairy cows.     

微多蛋白素饲喂产奶牛生物活性试验

微多蛋白素饲喂产奶牛试验,通过对试验组和对照组在各阶段产奶量变化的比较及乳品质量指标的测定表明,微多蛋白素饲喂产奶牛具有明显的增奶效果,其奶质量亦得到改善,产奶牛日粮添加微多蛋白素 １００ｇ／头,可增奶 １．７９ｋｇ／头,替代豆饼组饲喂微多蛋白素 １００ｇ／·日,可增奶 ０．２７ｋｇ／头·日。     

玉米秸秆生物产氢菌的分离培养及鉴定研究

以牛粪为菌种来源,利用玉米秸秆进行厌氧发酵产氢实验,在产氢效果达160 mL/h,秸秆产氢能力225 mL/g的最佳状态下,从实验中提取发酵菌液进行细菌的分离培养,并对产氢效果最好的R-3菌种进行生理生化试验研究和初步鉴定,确定产氢细菌为Clostridium sp.Fanp2.     

Exosomal Cargo May Hold the Key to Improving Reproductive Outcomes in Dairy Cows

The reproductive status of dairy cows remains a challenge for dairy farmers worldwide, with impaired fertility linked to a significant reduction in herd profitability, due in part to impaired immunity, increased metabolic pressure, and longer postpartum anestrous interval (PPAI). Exosomes are nanovesicles released from a variety of cell types and end up in circulation, and carry proteins, bioactive peptides, lipids, and nucleic acids specific to the place of origin. As such, their role in health and disease has been investigated in humans and animals. This review discusses research into exosomes in the context of reproduction in dairy herds and introduces recent advances in mass-spectrometry (MS) based proteomics that have a potential to advance quantitative profiling of exosomal protein cargo in a search for early biomarkers of cattle fertility.     

Lower temperature hydrothermal pretreatment improves the anaerobic digestion performance of spent cow bedding

The anaerobic digestion (AD) performance of spent cow bedding was investigated with different hydrothermal pretreatment (HP) conditions. Spent cow bedding was pretreated with low temperatures (50, 70, and 90℃) and different pretreatment times (2-72 h) with ammonia and without ammonia. The results showed that spent cow bedding was a good raw material for AD. After pretreatment, the concentration of volatile fatty acids (VFAs) in the group of hydrothermal pretreatments with ammonia (HPA) was higher than that in the HP group at the same pretreatment temperature and time. The optimal pretreatment condition was achieved with an HPA of 50℃ holding for 72 h. At the optimal condition, the highest concentration of VFAs was 1.58-10.85 times higher than that of the other pretreated groups. The highest hemicellulose and lignin removal rates were 58.07% and 10.32%, respectively. The highest methane yield was 163.0 ml·(g VS)^-1, which was 48.9% higher than that of the untreated group. The VFAs, pH, and reducing sugars showed positive relationships with the methane yield. Therefore, HP at low temperature can enhance the AD performance of spent cow bedding.     

Hay to reduce dietary cation-anion difference for dry dairy cows

Timothy grass has a lower dietary cation-anion difference [DCAD = (Na + K) - (Cl + S)] than other cool-season grass species. Growing timothy on low-K soils and fertilizing it with CaCl₂ could further decrease its DCAD. The objective of this study was to evaluate the effects of feeding low-DCAD timothy hay on dry dairy cows. Six nonpregnant and nonlactating cows were used in a replicated 3 × 3 Latin square. Treatments were as follows: 1) control diet (control; DCAD = 296 mEq/kg of dry matter); 2) low-DCAD diet based on low-DCAD timothy hay (L-HAY; DCAD = - 24 mEq/kg of dry matter); and 3) low-DCAD diet using HCl (L-HCl; DCAD = - 19 mEq/kg of dry matter). Decreasing DCAD with L-HAY had no effect on dry matter intake (11.8 kg/d) or dry matter digestibility (71.5%). Urine pH decreased from 8.21 to 5.89 when L-HAY was fed instead of the control. Blood parameters that decreased with L-HAY were base excess (− 0.4 vs. 3.8 mM) and HCO₃⁻ (23 vs. 27 mM), and blood parameters that increased were Ca²⁺ (5.3 vs. 5.1 mg/dL), Cl⁻ (30.5 vs. 29.5 mg/dL), and Na⁺ (60.8 vs. 60.1 mg/dL). Compared with the control, L-HAY resulted in more Ca in urine (13.4 vs. 1.2 g/d). Comparing L-HAY with L-HCl, cow dry matter intake tended to be higher (11.5 vs. 9.8 kg/d), and blood pH was higher (7.37 vs. 7.31). Urine pH; total dry matter; Ca, K, P, and Mg apparent absorption; and Ca, K, Na, Cl, S, P, and Mg apparent retention were similar. Absorption as a percentage of intake of Na and Cl was lower for L-HAY as compared with L-HCl. In an EDTA-challenge test, cows fed L-HAY regained their initial level of blood Ca²⁺ twice as quickly as the control treatment (339 vs. 708 min); there were no differences between L-HAY and L-HCl. This experiment confirms that feeding low-DCAD hay is an effective means of decreasing the DCAD of rations and obtaining a metabolic response in dry dairy cows.     

The effect of out-wintering pad design on hoof health and locomotion score of dairy cows

This study compared locomotion, hoof health, and lameness of dairy cows confined in either indoor free stalls (FS) or 1 of 3 out-wintering pad (OWP) designs. Out-wintering pad treatments were 1) uncovered OWP with a concrete feed apron (UP); 2) covered OWP with a concrete feed apron (CO); and 3) uncovered OWP on top of which grass was ensiled so that the cows could self-feed (SP). Cows were assigned to treatment at drying off using a randomized complete block design. They remained on treatment until calving, when they were turned out to pasture. Sole lesions, heel erosion, dermatitis, and claw hardness on both hind feet were scored according to severity at assignment to treatment, at calving, and 9 and 14 wk postpartum. Locomotion score was recorded weekly after calving for 14 wk. Incidence of clinical lameness was recorded during the treatment period and in the subsequent lactation. Treatment had no effect on sole lesion score, but scores increased over time (calving = 5.5 ± 1.3, wk 9 = 10.8 ± 1.3, wk 14 = 14.2 ± 1.3, mean ± SE). Self-fed cows had higher heel erosion scores (6.4 ± 0.4) than FS and CO cows (4.7 ± 0.4 and 4.7 ± 0.4, respectively) at calving. Cows on SP had the highest dermatitis scores [1.14 (0-2) mean (interquartile range)] and FS cows the lowest [0.51 (0-0)]. Hooves were hardest at assignment to treatment (43.9 ± 0.6) with a significant reduction in hardness at calving (40.0 ± 0.6). The hooves of CO cows were harder than those of SP and UP cows (CO = 43.3 ± 0.7, SP = 41.7 ± 0.7, UP = 41.7 ± 0.7, Shore D scale). There was no treatment effect on locomotion scores or lameness incidence. Higher dermatitis scores and heel erosion in SP may be due to exposure to excreta and moisture, because the SP treatment had no manure removal system at the feed face. In FS, the alleys and the feed face were cleaned regularly by automatic scraper, explaining the lower dermatitis scores recorded indoors. Providing shelter for OWP likely reduced exposure to environmental moisture. This ensured that the hooves of CO cows remained as hard as those of FS cows. Low correlations between hardness and pathologies indicate that other factors are involved in the development of hoof pathologies. Confining dry dairy cows on OWP does not increase locomotion scores or lameness incidence.     

Effects of milking frequency on phagocytosis and oxidative burst activity of phagocytes from primiparous and multiparous dairy cows during early lactation

The objective of this study was to investigate the effect of milking frequency on the phagocytosis and respiratory burst activity of polymorphonuclear neutrophils (PMN) and monocytes of primiparous and multiparous cows under 2 nutritional management regimens during early lactation. At calving, 12 primiparous and 12 multiparous cows were randomly assigned to 1 of 4 treatments, in which animals were milked once (OAD) or twice a day at a high or low nutritional level. Blood samples were taken 1 to 7 d before calving (prepartum) and 1 to 7, 14 to 21, and 42 to 49 d postpartum. Phagocytic and oxidative burst activity of PMN and monocytes were determined in whole blood and analyzed separately by flow cytometry. Once-a-day milking reduced significantly the percentage of phagocytic PMN and tended to decrease the number of bacteria ingested by these cells. The percentage of oxidative burst positive cells and overall respiratory burst activity of monocytes also tended to be reduced by OAD milking. The reduction of oxidative burst activity of monocytes was more pronounced 1 to 7 d postpartum compared with the prepartum sample and other postpartum samples. Oxidative burst activity of PMN and monocytes of multiparous cows was impaired compared with primiparous cows. The percentage of oxidative burst positive monocytes from multiparous cows was reduced prepartum and also 1 to 7 d postpartum. Once-a-day milking reduced the mean respiratory burst activity of PMN from primiparous cows to levels similar to that of multiparous cows. Therefore, an OAD milking regimen reduces phagocytic activity of PMN and monocytes and would be detrimental for the immune system in high-yielding dairy cows during early lactation.     

Risk factors associated with colostrum quality in Norwegian dairy cows

The objectives of the present study were to evaluate colostrum quality in Norwegian dairy cows based on IgG content, and to identify associations between possible risk factors and low colostral IgG. A longitudinal cross-sectional survey on calf health in Norway was performed between June 2004 and December 2006. The participating dairy herds were randomly selected among herds registered in the Norwegian Dairy Herd Recording System as having at least 15 cow years. The participating farmers were requested to sample 10 mL of colostrum from the first milking after calving from 12 cows that had calved during the defined project period of 365 d. Colostrum samples from 1,250 cows from 119 herds were collected. The material consisted of 451, 337, 213, and 249 samples collected from cows in their first, second, third, and fourth parity or more, respectively. Analysis was performed on IgG content by using single radial immunodiffusion. Mixed models with herd as a cluster were fit by using grams of IgG per liter of colostrum as the dependent variable for the statistical analyses. The IgG content in the colostrum sampled ranged from 4 to 235 g/L, with a median of 45.0 g of IgG/L, with the 10th, 25th, 75th, and 90th percentiles being 23.1, 31.4, 63.6, and 91.6 g of IgG/L, respectively. Altogether, 57.8% of the samples contained less than the desired 50 g of IgG/L of colostrum. Cows in their fourth parity or more were found to have significantly higher levels of IgG per liter of colostrum than cows in their first or second parity. Colostrum from cows in their second parity had the lowest level of IgG. Cows calving during the winter months (December, January, and February) produced colostrum with a significantly lower IgG content compared with cows calving in any other season of the year. Somatic cell count, measured after calving, was significantly higher in cows producing colostrum of inferior quality compared with those producing high-quality colostrum. Of the total variation in colostrum quality, 13.7% could be explained by cluster effects within herd. The variation in IgG content in colostrum produced by Norwegian dairy cows indicates a need for improved colostrum quality control and subsequent adjustment of the colostrum feeding regimen to ensure a protective immunological status for newborn calves.