Effect of Feeding Mixed Forage Diets on Milk Production

End of Project ReportsFor dairy farmers involved in winter milk production a high intake of forage is required by autumn calved dairy cows to produce a high milk yield with a moderate level of concentrate supplementation. Since intake of grass silage is often limiting, alternative forages or feeds may be needed to maximise forage intake. In areas not suitable for growing maize alternative forages need to be considered. These could include limited amounts of very high quality grass silage (DMD 750-800 g /kg), grazed autumn pasture or bulky by-product feeds, e.g. superpressed sugar beet pulp. An experiment was conducted involving 5 treatments in which a standard good quality grass silage (S) was partially replaced with either very high quality grass silage, which was either unwilted (U) or wilted (W), ensiled pressed sugar beet pulp (P) or with autumn pasture (G). These additional feeds were fed at a level of 5 kg DM/day to autumn calved cows in early lactation over a period of 8 weeks from late October to late December. The pressed pulp diet (P) included 0.5 kg DM soyabean meal to increase its protein level. The autumn grass was cut daily and fed indoors. The additional feeds were fed on top of the standard silage in individual feeding boxes and the standard silage was fed ad libitum to cows on all treatments. The cows were fed concentrates at 6 kg/day in two feeds on all treatments. The digestibility of the standard grass silage (754 g DMD/kg) was higher than planned and was only slightly less than that of the high quality supplementary silages (783 g DMD/kg). Feeding the U and W silages did not increase total forage intake but did increase milk yield by 1.7 - 1.9 kg/day compared with silage S alone. Milk fat and protein concentration tended to be reduced on the diets containing U and W silages, consequently yield of fat and protein were not significantly increased compared with silage S. Forage intake was increased by 8% (0.8 kg DM/day) when silage S was supplemented with autumn grass and milk yield was increased by 1.5 kg/day without affecting milk composition. Intake of silage was reduced by 37% by feeding grass. Feeding the pressed pulp supplement (P) increased intake of forage (+1.1 kg DM/day), increased milk yield by 2.7 kg/day and also improved milk protein concentration and yield (+121 g/day). Cows gained in liveweight to a similar extent on all diets. It was concluded that feeding pressed pulp with a good quality grass silage had the greatest effect on forage intake and milk production whereas feeding high quality grass silages or autumn grass had a smaller effect. Larger increases in intake and milk production would be expected from these feeds if the standard grass silage was of lower digestibility (~700 g DMD/kg), similar to average quality first cut silage.European Union Structural Funds (EAGGF

The Corticomedial Amygdala and Learning in an Agonistic Situation in the Rat

Social agonistic behaviour of intact male rats is strongly reduced by the experience of defeat by a dominant male conspecific. Small electrolytic lesions in the corticomedial amygdala strongly affected this behavioural change due to defeat. No effects of the lesions were observed before and during the defeat. Some learning is still possible in corticomedial amygdala lesioned animals. A comparison of the effects of lesions made before the defeat with lesions made after the defeat revealed that the lesions primarily produce a retention deficit in social learning.

Maize silage for milk production - Part 2: Effect of concentrate quality and quantity fed withmaize silage based forages on milk production

End of Project ReportIn some of the studies outlined in Part 1 of this report, mixed forages containing grass silage and a high proportion (60%) of maize silages varying in maturity and starch content were supplemented with concentrates at different levels to compare the response in milk production with a maize silage based forage and with good quality grass silage as the sole forage. The most suitable type of energy ingredient in the concentrate, i.e. high starch or low starch, high fibre ingredients, as supplements to maize silage based forages or grass silage was investigated. A range of levels of crude protein in the concentrate were examined in one study to determine the optimum level of crude protein in the supplement for maize silage based forages compared with grass silage.European Union Structural Funds (FEOGA

Evaluation and Refinement of the French Protein System (PDI) under Irish Conditions

End of Project ReportThe CP and DM degradability of grazed grass (between April and October, inclusive) and grass silage samples (differing in cut number and treatment) was determined using the in situ technique and the results obtained were used to calculate the PDIE and PDIN values. The degradability data on 12 concentrate ingredients from a previous study (Woods, 2000) were used to estimate PDIE and PDIN values for these feedstuffs. The mean PDIE and PDIN values determined for grass were 81 g/kg and 127 g/kg DM, respectively and for grass silage were 60 g/kg and 94 g/kg DM. Regression analysis resulted in equations to predict the PDIN of samples of grazed grass (PDIN = 3.8 + 0.628 CP) (R²= 0.999) and grass silage (PDIN = 5.9 + 0.605 CP) (R²= 0.997), and the PDIE of grazed grass (PDIE = 181.4 - 0.104 NDF - 0.195 ash - 0.047 OMD) (R²= 0.987) and grass silage (PDIE = 27.7 + 0.083 DMD - 0.147 CP) (R²= 0.812). The PDIE and PDIN values of 11 of the 12 concentrate ingredients were similar to those used in the French Tables but the maize distillers’ grains in this study and those used in France would appear to be quite different products. The response to PDIE and PDIN in the diet of lactating cows was evaluated and the effect of better balancing the PDIE and PDIN supply on the efficiency of N utilisation was assessed. Twenty autumn calving cows were blocked in a complete Latin Square design and assigned to four different diets varying in PDIN and PDIE content. Each of the four treatments consisted of a concentrate, maize silage and grass silage in the proportions 37:38:25 on a DM basis. There were 4 periods of 4-week duration each. Diet A contained 92 g/kg DM of PDIE and 116 g/kg DM of PDIN. Diet B contained 103 g/kg DM of PDIE and 122 g/kg DM of PDIN. Diet C and D over supplied PDIN at 137 g/kg and 153 g/kg, respectively relative to PDIE at 111 g/kg DM. Dry matter intake increased significantly with the excess dietary PDIN relative to PDIE but there were no significant differences in milk yield and composition. Decreasing the supply of PDIE in the diet (i.e. diet A vs. B) resulted in no significant effect on milk or constituent yields but did significantly reduce the efficiency (kg milk / kg DMI) of milk production. There was also a significant reduction in the efficiency of milk produced per kg DMI with increasing dietary concentrations of PDIN and increasing PDIN: PDIE balance (B>C>D). Increasing the dietary PDIN from 122 to 153 g/kg DMI increased urine N (+54%), faecal N (+11%) and plasma urea concentrations (+75%). The results indicate that the optimum concentration of dietary PDI is approximately 103 g/kg DM for cows producing about 35 kg of milk per day. A better balance between PDIE and PDIN supply improves the efficiency of conversion of DM to milk and dietary protein

Systems of Winter Milk Production based on all Autumn Calving Cows

End of Project ReportA supply of winter milk is needed by certain milk processors for the production of high value dairy products with a short shelf life to balance the high level of commodity based products which are mainly manufactured from seasonal milk produced from spring calving herds. Winter milk is generally produced by suppliers with split calving herds. A proportion of the cows (30-50%) calve in Autumn (September-December) to supply winter milk for which they receive a winter bonus for a contracted supply for the months of October to February. The remainder of the herd calve in Spring (Feb-April) and produce milk mainly off grass for which no bonus is paid. This system evens out the supply of milk throughout the year but complicates management, as it involves running two herds on the farm, with two calving seasons, two breeding seasons and two sets of replacement heifers to be reared. Also there is no break from milking. A system of winter milk production based on calving all of the cows in Autumn would be simpler, as it would involve only one herd, with a break from milking in late Summer and would appeal to many winter milk producers. In this study the feasibility of operating an all Autumn calving herd was examined, in terms of management, calving, winter feeding, reproduction and summer grazing. The herd was located in the Ballyderown farm attached to the Moorepark Research Centre. Alternative winter feeding systems were put in place over a three year period to compare the feed requirements and milk production of each system. A control system based on grass silage as the sole forage was compared with one where grass silage was supplemented with extended grazing of grass in late Autumn and early Spring or with a system based on a mixed forage diet based on grass silage, maize silage, brewers grains or a brewers grains/beet pulp mix. Grass silage and maize silage was produced within each system and the cows on each system were grazed separately within their own farmlets. The overall stocking rate for each system was 2.7 cows/ha using 350 kg N fertiliser/ha in addition to cattle slurry. Cows were dried off in mid-late July and were grazed tightly until calving down. The calving season extended from early September to early December. Most cows calved down outdoors at pasture or in a calving paddock without assistance. Cows were housed from early November to late March and were allocated to their respective diets in batches according to milk yield, lactation number and calving date. The cows given access to winter grass were given a daily allocation of grass (6-8 kg DM/cow) and grazed between morning and evening milking

Genetic Variants of Milk Proteins - Relevance to Milk Composition and Cheese Production.

End of Project ReportObjectives: (i) to develop rapid screening procedures for the determination of milk protein polymorphism (genetic variants) (ii) to determine the frequency distribution of milk protein genetic variants in a large population of Irish Holstein-Friesians and to determine if there was an association between κ-casein variant and milk yield and composition in this group of animals, and (iii) to make Cheddar and low-moisture part-skim Mozzarella cheese from different κ-casein genetic variant milks and to assess any effect on cheese yield, composition and functional characteristics. Conclusions:Analysis of 6,007 individual Irish Holstein-Friesian milks showed that the phenotype distribution of the κ-casein BB variant was very low at 1.98% compared to 53.07% for κ-casein AA and 44.95% for κ-casein AB. While no statistically significant associations were observed between κ-casein variant and milk yield and composition, κ-casein BB variant milks had superior rennet coagulation properties to that of the AA or AB variants. Generally, κ-casein variant had little effect on compositional attributes of cheese apart from FDM (fat in dry matter) which was significantly higher in cheeses from κ-casein BB milk than in those from κ-casein AA milk. Generally, κ-casein variant had no significant effects on either primary or secondary proteolysis, or on the sensory and/or textural characteristics of Cheddar or Mozzarella cheese throughout ripening; or on the functional characteristics (e.g. flow and stretch) of baked Mozzarella on storage for 90 days at 4°C. However, κ-casein BB variant milk gave significantly higher actual, and moisture adjusted yields of Cheddar and Mozzarella cheese than either κ-casein AB or AA variant milks. For example, the moisture adjusted Cheddar yield from κ-casein BB milk was 8.2% higher than from κ-casein AA milk. In the case of Mozzarella, the moisture adjusted yield was 12% higher. Based on the results, it is estimated that the actual yield of cheese in a plant producing 20,000 tonnes per year from κ-casein AA milk would increase to approximately 21,180 tonnes of Cheddar, or 21,780 tonnes of Mozzarella if made from κ-casein BB milk. Where κ-casein AB milk is used instead of κ-casein BB milk, the estimated yield of Mozzarella would increase to 21,580 tonnes.Department of Agriculture, Food and the Marin

Genome-Wide Studies Reveal that H3K4me3 Modification in Bivalent Genes Is Dynamically Regulated during the Pluripotent Cell Cycle and Stabilized upon Differentiation

Indexación: Web of Science; Scopus.Stem cell phenotypes are reflected by posttranslational histone modifications, and this chromatin-related memory must be mitotically inherited to maintain cell identity through proliferative expansion. In human embryonic stem cells (hESCs), bivalent genes with both activating (H3K4me3) and repressive (H3K27me3) histone modifications are essential to sustain pluripotency. Yet, the molecular mechanisms by which this epigenetic landscape is transferred to progeny cells remain to be established. By mapping genomic enrichment of H3K4me3/H3K27me3 in pure populations of hESCs in G2, mitotic, and G1 phases of the cell cycle, we found striking variations in the levels of H3K4me3 through the G2-M-G1 transition. Analysis of a representative set of bivalent genes revealed that chromatin modifiers involved in H3K4 methylation/demethylation are recruited to bivalent gene promoters in a cell cycle-dependent fashion. Interestingly, bivalent genes enriched with H3K4me3 exclusively during mitosis undergo the strongest upregulation after induction of differentiation. Furthermore, the histone modification signature of genes that remain bivalent in differentiated cells resolves into a cell cycle-independent pattern after lineage commitment. These results establish a new dimension of chromatin regulation important in the maintenance of pluripotencyhttp://mcb.asm.org/content/36/4/61

Atrial fibrillation detection using insertable cardiac monitor after stroke: a real-word cohort study

First published: 09 November 2022Objective: This study aimed to report the real‐world atrial fibrillation (AF) diagnostic yield of the implantable cardiac monitor (ICM) in patients with stroke or transient ischemic attack (TIA), and compare it to patients with an ICM for unexplained syncope. Methods: We used patient data from device clinics across the United States of America with ICM remote monitoring via PaceMate™, implanted for stroke or TIA, and unexplained syncope. Patients with known AF or atrial flutter were excluded. The outcome was AF lasting ≥2 min, adjudicated by International Board of Heart Rhythm Examiners certified cardiac device specialists. Results: We included a total of 2469 patients, 51.1% with stroke or TIA (mean age: 69.7 [SD: 12.2] years, 41.1% female) and 48.9% with syncope (mean age: 67.0 [SD: 17.1] years, 59.4% female). The cumulative AF detection rate in patients with stroke or TIA was 5.5%, 8.9%, and 14.0% at 12, 24, and 36 months, respectively. The median episode duration was 73 (interquartile range: 10–456) min, ranging from 2 min to 40.9 days, with 52.3%, 28.6%, and 4.4% of episodes lasting at least 1, 6, and 24 h, respectively. AF detection was increased by age (adjusted hazard ratio [for every 1‐year increase]: 1.024, 95% confidence interval: 1.008–1.040; p = .003), but was not influenced by sex (p = .089). For comparison, the cumulative detection rate at 12, 24, and 36 months were, respectively, 2.4%, 5.2%, and 7.4% in patients with syncope. Conclusion: Patients with stroke or TIA have a higher rate of AF detection. However, this real‐world study shows significantly lower AF detection rates than what has been previously reported.Jean J. Noubiap, Gijo Thomas, Melissa E. Middeldorp, John L. Fitzgerald, Curtis Harper, Prashanthan Sander

Sex disparities in enrolment and reporting of outcomes by sex in contemporary clinical trials of atrial fibrillation

Background:Underrepresentation of females in randomized controlled trials (RCTs)limits generalizability and quality of the evidence guiding treatment of females. This study aimed to measure the sex disparities in participants' recruitment in RCTs of atrial fibrillation (AF) and determine associated factors, and to describe the frequency of outcomes reported by sex. Methods:MEDLINE was searched to identify RCTs of AF published between January 1, 2011, and November 20, 2021, in 12 top‐tier journals. We measured the enrollment of females using the enrollment disparity difference (EDD) which is the difference between the proportion of females in the trial and the proportion of females with AF in the underlying general population (obtained from the Global Burden of Disease). Random‐effects meta‐analyses of the EDD were performed, and multivariable meta‐regression was used to explore factors associated with disparity estimates. We also determined the proportion of trials that included sex‐stratified results. Results:Out of 1133 records screened, 142 trials were included, reporting on a total of 133 532 participants. The random‐effects summary EDD was−0.125 (95%confidence interval [CI] =−0.143 to−0.108), indicating that females were under‐enrolled by 12.5 percentage points. Female enrollment was higher in trials with higher sample size (750, adjusted odds ratio [aOR] 1.065, 95% CI:1.008–1.125), higher mean participants' age (aOR: 1.006, 95% CI: 1.002–1.009), and lower in trials conducted in North America compared to Europe (aOR: 0.945, 95% CI:0.898–0.995). Only 36 trials (25.4%) reported outcomes by sex, and of these 29(80.6%) performed statistical testing of the sex‐by‐treatment interaction. Conclusion:Females remain substantially less represented in RCTs of AF, and sex‐stratified reporting of primary outcomes is infrequent. These findings call for urgent action to improve sex equity in enrollment and sex‐stratified outcomes' reporting in RCTs of AF.Jean Jacques Noubiap, Gijo Thomas, Ulrich Flore Nyaga, John L. Fitzgerald, Celine Gallagher, Melissa E. Middeldorp, Prashanthan Sander