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An experiment was carried out to examine the effects of offering beef cattle five silage diets. These were perennial ryegrass silage (PRGS) as the sole forage, tall fescue/perennial ryegrass silage (FGS) as the sole forage, PRGS in a 50:50 ratio on a dry matter (DM) basis with lupin/triticale silage (LTS), lupin/wheat silage (LWS) and pea/oat silage (POS). Each of the five silage diets was supplemented with 4 and 7 kg of concentrates/head/day in a five silages × two concentrate intakes factorial design. A total of 90 cattle were used in the 121-day experiment. The grass silages were of medium digestibility and were well preserved. The legume/cereal silages had high ammonia N, high acetic acid, low lactic acid, low butyric acid and low digestible organic matter concentrations (542, 562 and 502 g/kg DM for LTS, LWS and POS, respectively). Silage treatment did not significantly affect liveweight gain, carcass gain, carcass characteristics, the instrumental assessment of meat quality or fatty acid composition of the M. longissimus dorsi muscle. In view of the low yields of the legume/cereal crops, it is concluded that the inclusion of spring-sown legume/cereal silages in the diets of beef cattle is unlikely to be advantageous.
An experiment was carried out to examine the effects of offering beef steers grass silage (GS) as the sole forage, lupins/triticale silage (LTS) as the sole forage, a mixture of LTS and GS at a ratio of 70:30 on a dry matter (DM) basis, vetch/barley silage (VBS) as the sole forage, a mixture of VBS and GS at a ratio of 70:30 on a DM basis, giving a total of five silage diets. Each of the five silage diets was supplemented with 2 and 5 kg of concentrates/head/day in a 5 × 2 factorial design to evaluate the five silages at two levels of concentrate intake and to examine possible interactions between silage type and concentrate intake. A total of 80 beef steers were used in the 122-day experiment. The GS was well preserved while the whole crop cereal/legume silages had high ammonia-nitrogen (N) concentrations, low lactic acid concentrations and low butyric acid concentrations For GS, LTS, LTS/GS, VBS and VBS/GS, respectively, silage DM intakes were 6.5, 7.0, 7.2, 6.1 and 6.6 (s.e.d. 0.55) kg/day and live weight gains were 0.94, 0.72, 0.63, 0.65 and 0.73 (s.e.d. 0.076) kg/day. Silage type did not affect carcass fatness, the colour or tenderness of meat or the fatty acid composition of the intramuscular fat in the longissimus dorsi muscle.
Prenatal adversity shapes child neurodevelopment and risk for later mental health problems. The quality of the early care environment can buffer some of the negative effects of prenatal adversity on child development. Retrospective studies, in adult samples, highlight epigenetic modifications as sentinel markers of the quality of the early care environment; however, comparable data from pediatric cohorts are lacking. Participants were drawn from the Maternal Adversity Vulnerability and Neurodevelopment (MAVAN) study, a longitudinal cohort with measures of infant attachment, infant development, and child mental health. Children provided buccal epithelial samples (mean age = 6.99, SD = 1.33 years, n = 226), which were used for analyses of genome-wide DNA methylation and genetic variation. We used a series of linear models to describe the association between infant attachment and (a) measures of child outcome and (b) DNA methylation across the genome. Paired genetic data was used to determine the genetic contribution to DNA methylation at attachment-associated sites. Infant attachment style was associated with infant cognitive development (Mental Development Index) and behavior (Behavior Rating Scale) assessed with the Bayley Scales of Infant Development at 36 months. Infant attachment style moderated the effects of prenatal adversity on Behavior Rating Scale scores at 36 months. Infant attachment was also significantly associated with a principal component that accounted for 11.9% of the variation in genome-wide DNA methylation. These effects were most apparent when comparing children with a secure versus a disorganized attachment style and most pronounced in females. The availability of paired genetic data revealed that DNA methylation at approximately half of all infant attachment-associated sites was best explained by considering both infant attachment and child genetic variation. This study provides further evidence that infant attachment can buffer some of the negative effects of early adversity on measures of infant behavior. We also highlight the interplay between infant attachment and child genotype in shaping variation in DNA methylation. Such findings provide preliminary evidence for a molecular signature of infant attachment and may help inform attachment-focused early intervention programs.
Agriculture is one of the major sources of methane in the UK and the major contribution is that from the ruminant animal. Most current inventories include emissions from growing and adult cattle and it has been assumed that the young calf contributes little to the methane flux. There is a dearth of information for young cattle (65-110 kg liveweight) and the objective here was to provide methane data for this group of ruminants to assist in improving the UK inventories for methane.
Nitrogen-deficient fibrous crop residues are widely used as basal diets in less developed countries, particularly in dry seasons when alternative foods are often in short supply. One approach to improving animal performance on crop residue based diets is to include a supplement of improved quality food to provide fermentable protein and energy. There are no established in vitro methods for investigating interactions between foods but the in vitro gas production method shows promise in this regard (Prasad et al., 1994). This paper describes the interactions observed in vitro; an accompanying paper (Murray et al., 1998) describes in vivo responses to supplementation and relationships between in vitro and in vivo data.
The in situ and in vitro techniques have been adopted to estimate the degradability of organic matter (OM) in the rumen on the basis that this provides an estimate of ATP for microbial protein synthesis. However this assumption may be incorrect since ATP production requires the fermentation of degraded carbohydrate and Beever (1993) has shown that some degraded hexose can be used synthetically without ATP production. In addition, degraded OM from protein is likely to produce less ATP than the same amount of degraded carbohydrate. The gas production (GP) technique measures end products of fermentation and may be a better guide to ATP production. On the assumption that the in situ and in vitro techniques provide satisfactory estimation of OM degradability, the work discussed here used the GP technique to estimate the effective unfermentable OM fraction of the degraded OM (EUFDOM) for a range of concentrate foods.
Ruminants in many less developed countries may consume poor quality roughages such as straws, stovers and senescent native pasture as a major part of their diet, particularly during the dry season when high-quality forages are in short supply. The majority of these roughages are high in fibre, low in protein and the intake of digestible nutrients often is not enough to meet maintenance requirements. Intake and digestibility of poor-quality roughages may be increased by supplementation. The response to supplementation can be attributed to an increase in the supply of nitrogen and/or readily fermentable carbohydrate, resulting in an increase in rumen cellulolytic micro-organisms and therefore enhanced fibre degradation.
When a food is ingested by a ruminant animal, the carbohydrate fraction of the food is fermented by the rumen micro-organisms to produce gas (predominantly carbon dioxide and methane) as well as volatile fatty acids (VFA). The gas production technique simulates this fermentation process and provides an estimate of both the rate and extent of fermentation. Comparing the gas production (GP) profiles of foods enables a comparison to be made of the fermentative characteristics of different foods. However, the technique uses a bicarbonate-based medium system with the rumen liquor. This complicates the GP profile because of the production of ‘indirect’ gas resulting from the reaction between the VFA and the bicarbonate ions.
Beuvink and Spoelstra (1992) measured the volume of gas produced from buffered rumen fluid when known amounts of VFA were added and observed that 20·8 ml gas were released per mmol VFA. However, there is variation between laboratories in terms of the composition of the medium that is used. Even when the same medium is used, significant differences have been observed in the GP profile when different types of apparatus were employed (Rymer and Givens, 1997). Media are gassed with carbon dioxide before they are added to the gas production system and it is possible that the concentration of carbon dioxide dissolved in the medium varies between experiments. The objective of this experiment, therefore, was to determine whether the volume of indirect gas produced was affected by the composition of the medium, the addition of carbon dioxide, and the technique employed to measure gas production.
Fat content is one of the main factors affecting the degradability and fermentability characteristics of oil-rich foods estimated by means of the in situ, in vitro and gas production techniques. Filtered fat, considered degraded/fermented, is of limited value to the rumen microbes and may inhibit fermentation. Pre-extraction of oil may be one way to solve this problem. The rumen organic matter degradability (OMD) and fermentability (FOM) of concentrate foods were evaluated in this study with and without oil extraction.
Pell and Schofield (1993) described a gas production technique where cumulative pressure is related to gas production and hence organic matter (OM) fermentation. This technique has been used to describe rates of carbohydrate degradation for use in the Cornell net carbohydrate and protein system (CNCPS, Barry et al., 1994). Increasingly the CNCPS model is being utilized in the United Kingdom (UK) to ration dairy cows and, as a result, a UK foodstuff database has been developed containing the chemical description of the protein and carbohydrate pools. It was necessary to establish whether the gas production technique could be reproduced in a UK laboratory in order to provide rates of fermentation of the carbohydrate pools. Gas production techniques commonly used in the UK do not allow the vessel gas pressure to accumulate so a comparison of methodology was required.
Whilst it is recognized that most foods contain a number of different carbohydrate pools most applications of the gas production technique do not allow them to be differentiated despite their likely different nutritional attributes. Schofield and Pell (1995) reported that improved fermentation kinetics of the carbohydrate pools could be obtained by making gas production measurements on the whole food and on its neutral-detergent fibre (NDF) fraction, the data on the neutral-detergent solubles (NDS) being calculated by difference. More recently Doane et al. (1996) proposed an expansion of this to include incubation of the ethanol insoluble residue, to enable the NDS fraction of the food to be separated into a soluble carbohydrate and organic acids fraction and a starch and pectin fraction. Another approach is that of Groot et al. (1996) who used a multiphasic model of whole food gas production to show that the gas is produced from more than one food fraction. The objective of the present work was to combine these two approaches to examine the value of the multiphasic model applied to gas production from the isolated NDF and NDS fractions.
Cost effective performance from birth to slaughter must be achieved in order for beef producers to maximise income and survive in a subsidy-free, market led environment. The aim of the present study was to evaluate the effects of gender, plane of nutrition during the growing and finishing indoor feeding periods, and stocking rate and concentrate supplementation from weaning to finishing on meat quality.
A considerable proportion of beef produced in the UK is a byproduct of the dairy industry. Young animals from this source are generally regarded as low in quality and meat from animals of this type is usually destined for the commodity minced beef market. The objective of the present study was to evaluate the effect of slaughter weight on sensory characteristics of meat from Holstein-Friesian bulls and steers offered a cereal-based ration.
Meat from Holstein-Friesian bulls, which are bred for dairy traits, is generally regarded as low quality and is usually destined for the commodity (mince) market. However, given their ready availability as a by-product from the dairy herd, it is important to determine if meat from these animals would be suited to higher-priced markets. Furthermore, meat from bulls is generally considered to be lower quality than that from steers, though there is a paucity of data comparing meat from both sources. Hence, the objective of this study was to evaluate the effect of slaughter weight on meat quality characteristics of Holstein-Friesian bulls and steers offered a cereal-based ration.
Feed is a major cost in beef production during the winter feeding period. One potential method of reducing cost is to purchase grain at harvest. However, grain must be processed either by rolling or milling prior to feeding and this is a labour intensive process. Currently labour is an expensive and scare resource on many beef units. Recently different techniques have been developed for storing and feeding grain to beef cattle, which involve the processing of the grain prior to storage. The objective of the current study was to evaluate the effects of grain storage and processing method, and grain feed level on the meat quality of beef cattle offered two contrasting grass silages.
There is much interest in the manipulation of the fatty acid composition of milk fat so as to improve its health characteristics in the human diet. In an earlier study there was an indication that the concentration of fatty acids in milk may change with time when feeding whole oilseeds rich in polyunsaturated fatty acids (PUFA). In particular a tendency for an increase in CLA and C18:1 and a reduction in C18:2 and C18:3 concentrations with time were seen. The present study was therefore undertaken to examine the changes in the fatty acid composition of milk from high yielding dairy cows fed diets rich in monounsaturated fatty acids (MUFA) or PUFA over an extended period.
The most important factors known to influence the eating quality of beef are well established and include both pre- and post-slaughter events with many of the determinants interacting with each other. A substantial programme of work has been conducted by the Agri-Food and Biosciences Institute in Northern Ireland aimed at quantifying those factors of most importance to the local beef industry. Post-slaughter effects such as carcase chilling and electrical stimulation, ageing, carcase hanging and cooking method have been shown to have a significant impact on eating quality when compared with pre-slaughter activities such as animal handling and lairage time in the Northern Ireland studies. However, the effect of animal breed, particularly the use of dairy breed animals, was shown to significantly improve eating quality. Many of these factors were found to interact with each other.
Dolginov (1977) pointed out that a non spherical distribution of molecular weight μ can drive a Biermann type “battery” mechanism in a star and so generate a toroidal magnetic field. We consider uniformly rotating axisymmetric models of this type, containing a ‘primeval’ poloidal field, in which the currents maintaining the toroidal field flow along poloidal field lines, thus ensuring that the configuration is torque free. When the molecular weight distribution is chosen so as to produce a meridional circulation which exactly cancels the Eddington-Sweet circulation, then battery fields of order 1000 gauss can be maintained against ohmic decay in models appropriate to Ap stars near the main sequence with period of order 5 days.
This study explores an excellent mid-latitude Oligocene calcareous neritic succession that spans the Eocene/Oligocene boundary to the Miocene. Rapid changes in sea level and climate should have a palpable influence on macroevolution and the Eocene-Oligocene transition marks one of the most substantial changes for the Cainozoic.
Stratigraphic ranges of some 130 benthic and 20 planktic species occurring in two contrasting marine environments, one relatively restricted (low plankton - Murray Basin) and another more open (high plankton - Otway Basin) to oceanic processes, were identified and correlated with signals derived from changes in the physical environment. The signals include: the ‘Exxon’ sea-level curve, deep sea stable isotope curves, and prominent lithological changes.
There is a significant turnover of species at the Eocene/Oligocene boundary. This event impacts on all assemblages and correlation metrics indicate that there is an ‘across-the-board’ response. Interestingly, the turnover corresponds to a local Saint Vincent Basin lithological change from the grey-green, organic rich facies of the Blanche Point Formation to the red-yellow-brown, well oxidized, quartz and bryozoa rich facies of the Port Willunga Formation. This switch is in turn coincident with the saltatory positive deviation in the δ18O top and bottom water curves derived from oceanic sections.
The turnover pattern is not repeated at the major sea level fall predicted for the mid Oligocene (at 30 million years), neither is there any comparable lithological transition. Geographically widespread species (common to all environments) cross this supposed prominent type one sequence boundary, there is a signal but the impact on the fauna is less than that detected for the Eocene/Oligocene boundary. Those faunas that were more restricted to open ocean processes exhibited shorter stratigraphic ranges and appeared to be controlled primarily by sea level fluctuation and salinity changes. There is evidence to suggest that foraminiferal faunas of the more restricted environment in southern Australia were less responsive to the well mixed, thermohaline driven ocean of the Oligocene. Generally, Oligocene benthic assemblages are dominated by Cibicides, Notorotalia and Buliminid species in consistently high numbers, indicating a high dominance of relatively few taxa, that is, large populations and low diversity. Faunas of open ocean assemblages demonstrate relatively subdued turnover patterns compared to those of more restricted environments.
The Late Eocene displays parallel patterns of foraminiferal turnover and the Oligocene is characterised by inter-basin contrasts. In comparison to the Eocene, faunas appear to be more robust in the psychrosphere constrained ocean of the Oligocene. It is proposed that these patterns indicate that the Latest Eocene was dominated by species adapted to a specialist life strategy while the Oligocene reflect patterns more often associated with opportunist colonization.
We have studied axisymmetric nonlinear αω-dynamo models taking the interaction between even and odd parities fully into account. It turns out that the dominating type of symmetry is not always determined uniquely, but it can vary on a very long time scale compared to the period of the magnetic cycle. In some cases the frequency of this long term variation is close to the beat frequency of the two solutions with purely dipolar and purely quadrupolar parity. The occurrence of a second frequency is typical of solutions whose trajectory describes a torus in the phase space. We argue that this finding is of relevance for understanding secular variations observed in the Sun. For example measurements of sunspots indicate that the spot number on the northern hemisphere at present exceeds the number on the southern hemisphere. The reverse seems to have been the case at the end of last century.