Comparison of a Calan gate and a conventional feed barrier system for dairy cows: feed intake and cow behaviour

peer-reviewedThere is little published information on comparisons of individual and group feeding systems for dairy cows. Twenty-four dairy cows were used in a three-period incompletely balanced, change-over design study, to examine food intake and feeding behaviour of dairy cows offered their food via group-access electronic Calan gates, or via a conventional feed-barrier system. The food offered was in the form of a complete diet, and comprised grass silage and concentrates (60:40 dry matter (DM) basis). With the conventional feed-barrier system a maximum of eight animals were able to feed at any one time, while the Calan-gate system allowed a maximum of three animals to feed at any one time. Method of offering the ration had no effect on daily DM intake. During the 8-h period after animals were given access to fresh food, the mean number of animals feeding at any one time was 5.4 and 3.0 for the conventional and Calan-gate systems, respectively, while total intake over this period was 11.0 and 9.2 kg DM per cow, respectively. When access to feed was restricted by the use of Calan gates, animals responded by increasing their intake rate. It is concluded that total DM intake was unaffected by the use of a group Calan-gate feeding system as animals modified their feeding behaviour to maintain food intake

Impact of slurry application method on phosphorus loss in runoff from grassland soils during periods of high soil moisture content

peer-reviewedPrevious studies have reported that the trailing shoe application technique reduces phosphorus (P) in the runoff postslurry application when compared to the traditional splash-plate application technique. However, the effectiveness of the trailing-shoe technique as a means of reducing P losses has not been evaluated when slurry is applied during periods of high soil moisture levels and lower herbage covers. To address this issue, three treatments were examined in a 3 × 4 factorial design split-plot experiment, with treatments comprising three slurry treatments: control (no slurry), splashplate and trailing-shoe, and four slurry application dates: 7 December, 18 January, 1 March and 10 April. Dairy cow slurry was applied at a rate of 20 m3/ha, while simulated runoff was generated 2, 9 and 16 days later and analysed for a range of P fractions. Dissolved reactive P concentrations in runoff at day two was 41% lower when slurry was applied using the trailing-shoe technique, compared to the splash-plate technique (P < 0.05). In addition, P concentrations in runoff were higher (P < 0.05) from slurry applied in December and March compared to slurry applied in January or April, coinciding with periods of higher soil moisture contents. While the latter highlights that ‘calendar’-based non-spreading periods might not always achieve the desired consequences, the study demonstrated that further field-scale investigations into the trailing shoe as a mitigation measure to reduced P loss from agricultural soils is warranted

A short survey of key silage-making practices on Northern Ireland dairy farms, and farmer perceptions of factors influencing silage quality

peer-reviewedNorthern Ireland dairy farmers (n = 174) were surveyed to identify key silage-making practices, and factors perceived to influence the quality of grass silage made on their farms. The majority of farmers (65%) harvested grass for silage three times/year: 62% normally used a contractor, while 47% routinely used a silage additive. Delays to mowing and delays to harvesting due to adverse weather or poor ground conditions were perceived to have a large or very large impact on silage quality (68% and 53% of farmers, respectively). Inadequate wilting, poor-quality swards on owned land, on rented land and “contamination” of first-cut grass with autumn or winter growth herbage were all perceived as having a large or very large impact on silage quality (32%, 27%, 40%, 30% of farmers, respectively). Over the previous decade, 11%, 41% and 37% of farmers claimed a small, moderate or large improvement in silage quality, mainly due to earlier cutting of grass and ensiling better quality swards

Immunological effects of altering the concentrate inclusion level in a grass silage-based diet for early lactation Holstein Friesian cows

Concentrate inclusion levels in dairy cow diets are often adjusted so that the milk yield responses remain economic. While changes in concentrate level on performance is well known, their impact on other biological parameters, including immune function, is less well understood. The objective of this study was to evaluate the effect of concentrate inclusion level in a grass silage-based mixed ration on immune function. Following calving 63 (45 multiparous and 18 primiparous) Holstein Friesian dairy cows were allocated to one of three isonitrogenous diets for the first 70 days of lactation. Diets comprised of a mixture of concentrates and grass silage, with concentrates comprising either a low (30%, LC), medium (50%, MC) or high (70%, HC) proportion of the diet on a dry matter (DM) basis. Daily DM intakes, milk yields and BW were recorded, along with weekly body condition score, milk composition and vaginal mucus scores. Blood biochemistry was measured using a chemistry analyzer, neutrophil phagocytic and oxidative burst assessed using commercial kits and flow cytometry, and interferon-γ production evaluated by ELISA after whole blood stimulation. Over the study period cows on HC had a higher total DM intake, milk yield, fat yield, protein yield, fat+protein yield, protein content, mean BW and mean daily energy balance, and a lower BW loss than cows on MC, whose respective values were higher than cows on LC. Cows on HC and MC had a lower serum non-esterified fatty acid concentration than cows on LC (0.37, 0.37 and 0.50 mmol/l, respectively, P=0.005, SED=0.032), while cows on HC had a lower serum β-hydroxybutyrate concentration than cows on MC and LC (0.42, 0.55 and 0.55 mmol/l, respectively, P=0.002, SED=0.03). Concentrate inclusion level had no effect on vaginal mucus scores. At week 3 postpartum, cows on HC tended to have a higher percentage of oxidative burst positive neutrophils than cows on LC (43.2% and 35.3%, respectively, P=0.078, SED=3.11), although at all other times concentrate inclusion level in the total mixed ration had no effect on neutrophil phagocytic or oxidative burst characteristics, or on interferon-γ production by pokeweed mitogen stimulated whole blood culture. This study demonstrates that for high yielding Holstein Friesian cows managed on a grass silage-based diet, concentrate inclusion levels in early lactation affects performance but has no effect on neutrophil or lymphocyte immune parameters

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

The Cholecystectomy As A Day Case (CAAD) Score: A Validated Score of Preoperative Predictors of Successful Day-Case Cholecystectomy Using the CholeS Data Set

Background Day-case surgery is associated with significant patient and cost benefits. However, only 43% of cholecystectomy patients are discharged home the same day. One hypothesis is day-case cholecystectomy rates, defined as patients discharged the same day as their operation, may be improved by better assessment of patients using standard preoperative variables. Methods Data were extracted from a prospectively collected data set of cholecystectomy patients from 166 UK and Irish hospitals (CholeS). Cholecystectomies performed as elective procedures were divided into main (75%) and validation (25%) data sets. Preoperative predictors were identified, and a risk score of failed day case was devised using multivariate logistic regression. Receiver operating curve analysis was used to validate the score in the validation data set. Results Of the 7426 elective cholecystectomies performed, 49% of these were discharged home the same day. Same-day discharge following cholecystectomy was less likely with older patients (OR 0.18, 95% CI 0.15–0.23), higher ASA scores (OR 0.19, 95% CI 0.15–0.23), complicated cholelithiasis (OR 0.38, 95% CI 0.31 to 0.48), male gender (OR 0.66, 95% CI 0.58–0.74), previous acute gallstone-related admissions (OR 0.54, 95% CI 0.48–0.60) and preoperative endoscopic intervention (OR 0.40, 95% CI 0.34–0.47). The CAAD score was developed using these variables. When applied to the validation subgroup, a CAAD score of ≤5 was associated with 80.8% successful day-case cholecystectomy compared with 19.2% associated with a CAAD score >5 (p < 0.001). Conclusions The CAAD score which utilises data readily available from clinic letters and electronic sources can predict same-day discharges following cholecystectomy

A comparison of the feeding and grazing behaviour of primiparous Holstein-Friesian and Jersey × Holstein-Friesian dairy cows

Peer-reviewed articleFood intake and feeding behaviour of Holstein-Friesian (HF) and Jersey × Holstein- Friesian (J × HF) dairy cows (14 primiparous cows of each genotype) were measured during a 54-day confinement period [cows offered a complete diet comprising conserved forage and concentrates; 66:34 dry matter (DM) basis], while herbage intakes and grazing behaviour were measured on three occasions during a 96-day grazing period. Throughout the experiment HF cows had a higher milk yield than J × HF cows (P < 0.05), while fat + protein yield was unaffected by genotype. During the confinement period HF cows had a higher food intake than the J × HF cows (P < 0.01), although DM intake/kg metabolic live weight (live weight0.75) was unaffected by genotype. With the exception of the number of ruminating bouts/day (P < 0.05), and idling time/day (P < 0.05), both of which were highest with the J × HF cows, genotype had no significant effect on any of the feeding behaviours examined during the confinement period. Herbage intake did not differ between genotypes during the grazing period, although when expressed on a kg live weight0.75 basis, intakes were highest with the J × HF cows (P < 0.05). While the smaller J × HF cows had fewer grazing bouts per day (P < 0.01), the mean duration of each grazing bout was longer (P < 0.001), resulting in a longer total grazing time (P < 0.05) and a greater number of grazing bites each day (P < 0.01). The smaller crossbred cows had to ‘work harder’ during the grazing period to achieve the same intakes as the larger HF cows.Department of Agriculture and Rural Development for Northern Ireland (DARD); Agri-Searc

Effects of dietary crude protein concentration on animal performance and nitrogen utilisation efficiency at different stages of lactation in Holstein-Friesian dairy cows

Nitrogen (N) excretion from livestock production systems is of significant environmental concern; however, few studies have investigated the effect of dietary CP concentration on N utilisation efficiency at different stages of lactation, and the interaction between dietary CP levels and stages of lactation on N utilisation. Holstein-Friesian dairy cows (12 primiparous and 12 multiparous) used in the present study were selected from a larger group of cows involved in a whole-lactation study designed to examine the effect of dietary CP concentration on milk production and N excretion rates at different stages of lactation. The total diet CP concentrations evaluated were 114 (low CP), 144 (medium CP) and 173 (high CP) g/kg DM, with diets containing (g/kg DM) 550 concentrates, 270 grass silage and 180 maize silage. During early (70–80 days), mid- (150–160 days) and late (230–240 days) lactation, the same 24 animals were transferred from the main cow house to metabolism units for measurements of feed intake, milk production and faeces and urine outputs. Diet had no effect on BW, body condition score, or milk fat, protein or lactose concentration, but DM intake, milk yield and digestibilities of DM, energy and N increased with increasing diet CP concentration. The effect of diet on milk yield was largely due to differences between the low and medium CP diets. Increasing dietary CP concentration significantly increased urine N/N intake and urine N/manure N, and decreased faecal N/N intake, milk N/N intake and manure N/N intake. Although increasing dietary CP level significantly increased urine N/milk yield and manure N/milk yield, differences in these two variables between low and medium CP diets were not significant. There was no significant interaction between CP level and stage of lactation on any N utilisation variable, indicating that the effects of CP concentration on these variables were similar between stages of lactation. These results demonstrated that a decrease in dietary CP concentration from high (173 g/kg DM) to medium level (144 g/kg DM) may be appropriate for Holstein-Friesian dairy cow to maintain milk production efficiency, whilst reducing both urine N and manure N as a proportion of N intake or milk production