In the wetter parts of the UK where maize production is marginal, whole crop cereals can be used to boost milk yield from home grown forages, and thereby maintain profitability in the current climate of falling milk prices. In spite of the fact that barley and oat production are more suited to such wetter, marginal areas of the UK (Lockhart and Wiseman, 1978), most of the nutritional studies on whole crop cereals have been conducted on wheat. In Denmark which has a more established tradition of producing whole crop cereals, barley is the cereal of choice (Kristensen, 1992). This study therefore evaluated the chemical composition, in vivo digestibility and animal performance from fermented whole crop barley (WCB) and whole crop oats (WCO) to determine their potential as winter feeds in marginal areas of the UK.

Development of early maturing forage maize varieties has enabled the crop to be grown in more marginal areas of the UK, consequently the crop is harvested at a range of maturities and dry matter (DM) concentrations. Digestibility of maize silage DM is reported to remain relatively constant over a wide range of maturities; however very mature maize is known to suffer reduced DM digestibility (Bal, Coors and Shaver, 1997). The objective of this experiment was to measure nutrient digestibility of maize silage harvested at stages of maturity commonly experienced in the UK.

Crop maturity at harvest affects the intake potential of maize silage. A short feeding trial with young beef heifers (Browne, Bryant, Beever and Thorp, 1998) identified a significant depression in intake when low DM silage was fed, yet no significant effect on live weight gain was recorded. The objective of this experiment was to determine if these results were repeated in a longer intake study using finishing beef cattle and to examine the effect of maize maturity on carcass quality.

Forage maize was harvested at three stages of maturity (LOW, MED and HIGH) during September 1997. At each stage of maturity, the crop was cut and ensiled in a separate AgBag during one day, without the use of an additive. The respective silage DM concentrations were 297, 339 and 393 g/kgFWt.

There is considerable interest in the effect of dietary supplementation with probiotics or yeast cultures on dairy cow performance. Yeast cultures such as Diamond V ‘XP’ are produced by growing selected yeast strains on a semi-solid medium under stressed conditions, which are then dried. They are now used by a majority of the high yielding herds in North America (McCullough, 1995) and have been shown to have a significant effect on butterfat and protein yield with grass silage fed UK dairy cows (Rowlinson et al., 1995). The objective of this work was to evaluate the effect of feeding a yeast culture to a medium-high yielding (8,100 kg) herd of dairy cows fed a diet based on grass and maize silage.

Inflation of a balloon in the rumen of forage-fed ruminant animals depresses intake. This might be due to the unpleasant over-stimulation of stretch receptors or to mimicking the pleasant after-effects of eating. If the former then cows would be expected to avoid stimuli which they had learned to associate with distension, while if the latter, they should be attracted to such stimuli. The experiment reported here paired small meals of flavoured concentrates with inflation of a balloon in the rumen of dry cows on several occasions and examined their subsequent preferences for the flavour of concentrates.

12 individually-tethered adult Holstein cows, neither pregnant nor lactating, were fed freshly-chopped sugar cane ad libitum with 4 kg/day soya bean meal sprinkled over it. At 1200 h the basal food was removed and 30 min later 6 cows had a balloon inserted into the rumen via a cannula which was filled with 12 litres of water and remained in place for 120 min.

Diets based on restrictively fermented grass silage do not provide sufficient gluconeogenic precursors in high-yielding dairy cows (Huhtanen 1998). In principle, manipulating the glucose supply of cows may be done either by increasing the proportion of propionate in rumen volatile fatty acids or by increasing glucose supply to the intestines. The objective of this experiment was to compare casein, glucose, propionic acid, and starch as glucose sources in dairy cows fed diets based on restrictively fermented grass silage.

Four rumen cannulated Finnish Ayrshire cows 15-16 weeks into their 4. or 5. lactation were used in an experiment designed as a 4 x 5 incomplete Latin square with 14-d periods. The five treatmens allocated to four animals were continuous infusions of 1) water (Control), 2) casein 300 g/d (Cas), 3) glucose 300 g/d (G), 4) propionic acid 247 g/d (P) and 5) barley starch 270 g/d (S). Substrates dissolved in water were infused either into the rumen (P) or the abomasum (other substrates).

The current pricing structure of the UK milk industry considers milk quality with higher premiums paid for milk protein content than for fat. Attempts to alter milk protein content by feeding extra protein(Bequette et al.,1998) or infusing amino acids(AA) in dairy cows has not always given consistent results. The present study is the first in a series where the objective is to use explants prepared from rat mammary glands to start identifying which AA may be (limiting) most important in regulating milk protein synthesis. Such information could be useful to identify specific AA which should be supplemented in the diet of the cow.

Seasonal variation in feed supply, is recognised as an important constraint to animal production in the tropics. However, day to day fluctuations in quantity and quality of feed are also common in stall-fed animals on smallholder dairy farms. Opportunistic use of feeds available in small amounts, such as residues from food crops, weeds and purchased fodder is common. In addition, amounts of cut green fodder may be reduced or absent on some days. Ruminant animals require time to adapt to a given feed and it might be expected that frequent and abrupt changes of this type might have a negative effect on feed utilisation and animal performance. The objective of the experiment was to determine whether the way in which two fodders, with significantly different DM, CP and fibre contents, were offered, would influence digestibility and liveweight gain in cross-bred cattle.

The amount and source of nitrogen required to optimize microbial protein synthesis has been widely discussed in the literature. However, information available on factors affecting microbial protein synthesis in young heifers fed high concentrate diets is limited. Our objective was to study the effect of CP concentration on ruminal fermentation and urinary excretion of purine derivatives, used as an index of microbial yield, in heifers fed concentrate and barley straw, both ad libitum, from 100 to 230 kg LW.

Ten crossbreed beef heifers (101±4.5 kg LW), of which 6 where ruminally cannulated, were individually penned and randomly offered (115% of previous day consumption) a concentrate (14%, L or 17%, H) and barley straw diet once daily. Concentrates (H and L) were composed of ground corn (32; 38%), barley (27%), cassava (17%) and sunflower meal (5.8%) and soya bean meal included either at 16% or 9%, respectively.

Wheat is a good source of carbohydrates for ruminants, and recent low prices in the UK suggest that usage is likely to increase. However, there is a shortage of information on the digestibility of wheat in the rumen. Such information is vital for predicting the relative value of wheat as a source of fermentable metabolisable energy or by-pass starch. Digestibility is likely to be affected by growing conditions and genetics. Genetic differences are found between wheat varieties, but comparisons of named varieties yield limited information because many characteristics vary simultaneously. This problem can be overcome by using near-isogenic lines of wheat that vary only in a limited number of known characteristics. The objective of this study was to determine the rumen digestion characteristics of different near-isogenic wheat lines grown under the same agronomic conditions.

Alkanes have been used for a number of years to estimate food intake in ruminants. The technique requires animals to be dosed with synthetic even-chained alkanes, usually C32 and C36; faecal concentrations of these are then compared with naturally-occurring alkanes, e.g. C33, to estimate intake. Mayes et al. (1986) prepared capsules containing alkanes on shredded paper; Dove et al. (1988) used hard-shell gelatine capsules to administer dosed alkanes. Both methods required animal handling, extra material, like gelatine capsules or paper, and also some laboratory work for preparing alkane solutions, papers and capsules. We report here a less time-consuming method that can be used with dairy cows or other animals offered concentrates separately from a basal ration. The objective of the study was to see how accurately food intake in dairy cows could be estimated when dosed alkanes are administered via a compound feed.

The rate and extent of protein degradation in the rumen is very crucial, as it determines the availability of nitrogen to microorganisms and amino acids in the small intestine to the host animals. The protein consumed by the animal should be partly degradable in the rumen, as peptides and amino acids derived from proteolysis are thought to stimulate microbial growth and rumen fermentation under certain conditions. It is, therefore, very important to determine the degradability of different feed ingredients which are grown and used in different regions of the world. The present study was undertaken to assess the degradation characteristics of different protein sources grown and used in Turkey.

Dry matter intake (DMI) is a major limitation to milk production in dairy cows, but is difficult to measure under commercial conditions where cows are housed and fed in groups. Several methods have been developed to estimate DMI by individual cows, such as using inert markers, where dual markers can be used to predict digestibility and faecal output simultaneously. However, their scope is limited by the laboratory analyses required and there are problems with marker dosing and recovery. Predictions of DMI by near-infrared reflectance spectroscopy (NIRS) have been reported, but they have been based on scanning forage samples to predict intake potential. Since DMI is a function of the animal as well as the diet, it is more logical to scan samples of faeces when predicting individual intakes. The objective of this study was to see whether NIRS could accurately predict DMI from faecal samples of individual cows.

Earlier studies at the Centre for Dairy Research have examined the effect on feed intake and milk production of a range of by-products used in a total mixed ration (TMR) based on maize silage. These studies showed that distillers grains and molassed sugar beet feed (MSBF) could be used to replace cereal and protein supplements, with no effect on milk yield and dry matter (DM) intake but with a large reduction in milk fat and a little change in milk protein content. The aim of the current study was to examine the effect on feed intake and milk production of lactating dairy cows offered a TMR in which Stockmol 20, a molasses supplement (92 g/kg DM crude protein and 12.3 MJ ME/kg DM) and Regumaize 44, a high protein molasses urea based liquid (440 g/kg DM crude protein and 10.7 MJ ME/kg DM) were used to replace conventional energy and protein sources.

Ensiled grass is presently the major source of winter feed for dairy cows and other livestock in the UK. However, the quality and quantity of protein in grass silage tends to limit its use for milk production, which means that bought-in concentrate supplements must be fed to maintain high production levels. Whilst forage legumes such as red clover and lucerne appear to have potential as home-grown, protein-rich feeds for livestock (Frame et al., 1998), there is very little information available regarding their nutritive value when ensiled. The aim of this study was to compare the N balance of lambs offered red clover and lucerne silages harvested at two different growth stages.

Using new harvesting and ensiling technologies it is now possible to successfully ensile kale, thereby conserving the crop at the optimum time to achieve the best compromise between quality and quantity (Young et al., 1997). However, previous work with kale has concentrated on its value as a grazed crop, and consequently there is little information available regarding the optimum time for harvesting. The aim of this experiment was to compare the voluntary intake and in vivo digestibility by sheep of kale silage prepared at two different stages of growth, and to determine whether the use of an inoculant influenced nutritional quality.

In vitro methods for laboratory estimations of feed degradation are important tools for studying ruminant nutrition. These methods measure either substrate disappearance or fermentation products, the exact nature of which depends on the nature of the feed and the system being used to determine the digestibility. Consequently, there is a need for comparisons of in vitro and in vivo results, especially when new feeds are being assessed. The following study compared the gas production procedure to whole tract digestibility measurements for a range of alternative crop silages.

Round bale silages were prepared from five different alternative crops, red clover, lucerne clover, lotus, kale and a barley/pea bicrop, harvested at difference growth stages (Table 1). Freshly cultured Lactobacillus plantarum was used as an inoculant on half the material from each kale and barley/pea bi-crop harvest, and applied at a rate of 106 colony forming units per gram fresh forage.

Manchega (MN) and Lacaune (LC) are two semi-coarse-wooled dairy breeds with similar size but different milk yield, the latter producing twice as much milk as the former (Pérez, 1997). The aim of this experiment was to compare, under the same feed conditions, dry matter intake and performance in late pregnancy and lactation and digestive pools of these two breeds.

Twenty-four ewes, 12 per breed, were used in three different periods: late pregnancy (8 weeks), rearing (5 weeks) and milking (7 weeks). At lambing, average body weight was 74.4 vs 78.5 kg, for LC and MN, respectively. Dry matter intake (DMI), apparent dry matter digestibility (DMD), body condition score (BCS) and milk yield (MY) standardized according to Bocquier et al. (1993) were recorded.

Many sheep may require supplementation with cobalt or selenium, whilst many also require copper for the prevention of swayback. Often more than one are in short supply and blanket supplementation is often the answer, but this could result in problems of toxicity especially with copper in sheep. This trial was carried out on a flock known to be copper sufficient to investigate the supplementation of extra copper in the form of a sintered soluble glass bolus being used to supply selenium and cobalt to the flock.

Two batches of Lleyn sheep were selected, the first were forty ewe lambs, whilst the second set were thirty gimmers. The ewe lambs were randomly split into two groups one being given a copper, cobalt and selenium bolus (Cosecure®, Telsol Ltd) with the other group remaining untreated as controls.

Maximum concentrations of toxic metals in human food have been established for cadmium and lead independently, but both metals may be increased concurrently in sewage sludge and other forms of industrial pollution. Synergism exists between the two metals in their toxic effects (Kaji et al., 1995), which emphasises that the toxic thresholds cannot be prescribed for metals in isolation. An experiment was conducted that investigated the medium and long-term effects of adding lead to the diet of sheep, to determine whether the animal's metabolism would adapt to alter the effects of lead on the accumulation of other toxic metals.