Inter- and even intra-species variability exists in the ability of rumen inocula to digest forages using in vitro techniques. Differences in fermentation patterns between animal species may be due to the presence of different species within the microbial populations and/or to the fermentative capacity of the microflora (Sunvold et al., 1995). Several authors have reported that the host species affects the rumen microflora which therefore influences the in vitro activity of rumen fluid, even if two host species are given the same diet. Grant et al. (1974) concluded that after a sufficiently long adaptation period to the diet, there was no longer any significant difference between the rumen fluid from buffalo and cows. However, the results obtained by other authors (di Leila et al. 1995; Puppo et al., 1995) are in disagreement with these findings. The in vitro cumulative gas production technique (Theodorou et al., 1994), is increasingly being used as a method of food evaluation, by comparing the fermentability of different foods. One of the greatest sources of variation for this kind of method is due to differences in inocula. An experiment was carried out to determine whether rumen fluid from buffalo and cows given a similar diet, led to similar results for the evaluation of the same foods.

The growing demand for livestock products in the developing world is expected to drive livestock production in these countries. Delgado et al. (1999) predict that by 2020, developing countries will produce on average 38% more meat and 54% more milk per capita than in the early 1990s. The livestock revolution could then translate into opportunities for smallholder livestock producers. In the case of ruminants, much of this increase may occur in mixed farming systems, rather than through industrial production. In 1991–93, mixed systems produced 92% of the world's milk, and 54% of the world's meat (de Haan et al., 1997).

The Longhorn cattle breed has a long and prestigious history, dating back prior to the livestock pioneers of the 18th century. It was, for a period, the improved breed of choice in the Midland Counties. But the breed gradually fell from favour and, by the early 1970s, only 6 significant Longhorn herds remained in the UK. However, the Longhorn was one of many rare breeds to benefit from the growth of the rare breeds movement in the 1970s, led by the Rare Breeds Survival Trust. A number of factors have helped the breed to recover, including: an active breed society providing registrations and analyses based on these, promoting the breed, organising sales and shows and providing an important social framework for breeders and supporters; creation of a semen bank; niche marketing of meat and hides and the use of the breed in conservation grazing.

Sheep in the uplands of the United Kingdom face a series of choices as to where to graze. These choices have been shown to be influenced by the spatial distribution of nutrient supply from herbage (Duncan et al., 1994). Micro-climatic variation may also determine where animals forage, particularly in topographically complex environments found in upland areas. Wind and rain have marked effects on heat loss and hence on lower critical temperature (LCT) in sheep (Blaxter, 1977). Mount and Brown (1982) demonstrated that there were occasions during a year when sheep were below their LCT. This study assumed that data gathered from a standard meteorological station were applicable to conditions actually experienced by grazing animals and took no account of the ability of herbivores to select a more favourable micro-climate under extreme conditions (Mount and Brown, 1982). The experiment reported here was carried out to examine the extent to which microclimate influenced the distribution of grazing by sheep under windy conditions. Micro-climate was manipulated using artificial shelters.

The effects of breed, stage of lactation, age and seasonality on the compositional quality of milk are discussed. The Jersey breed has the highest fat and protein contents, 51.9 and 38.5 g/kg milk, respectively, followed by the Guernsey breed, with 46.4 and 36.3 g/kg milk. The British Holstein has the lowest fat and protein contents, at 37.3 and 32.0 g/kg milk, respectively, whilst the Ayrshire is intermediate between the Channel Island and the Friesian and Holstein breeds. The range of fat within a breed may be over 20 g/kg milk. The variation in protein content is less than this value but may be over 10 g/kg milk. Lactose values vary less than those for fat and protein. Mean lactose values are 45.5 g/kg, with a range from 41.0 to 50.0 g/kg milk.

The protein content of milk is high in early lactation, falls rapidly to reach a minimum at approximately 6 weeks after calving, increases slowly to 6 months after calving and then increases rapidly to the end of lactation. The fat content of milk is also high in early lactation and falls to a minimum between the 6th and 10th weeks of lactation. It then rises in a manner similar to protein. Converse changes occur with lactose: the content is low in colostrum and increases to twice its initial value within the 1st week. It remains steady until the 5th or 6th week of lactation, after which it declines slowly and then more rapidly towards the end of lactation.

The fall in the fat content of milk from the 1st to the 5th lactation is progressive and of the order of 2 g/kg milk. Solids-not-fat content declines by approximately 4 g/kg. This fall in solids-not-fat is largely a fall in lactose; the change in protein content is small. In Friesian herds, a decrease in average lactose content from 46.9 to 44.7 g/kg milk from 1st to 3rd lactation and over has been observed.

The average fat content of bulk milk in England and Wales is highest in October and November and lowest in May and June. The protein content of milk falls to a low level in March, rises rapidly during April and May and shows a slight fall in July, followed by an increase until October, when a progressive fall occurs during the winter months. The lactose content of milk does not vary as much as protein, with values being 0.5 g/kg higher in June and 0.8 g/kg lower in September than the overall average.

The commonality in neural mechanism (transmitter and brain region) underpinning stereotypy and that associated with motivation of goaldirected behaviours lends support to the idea that the former is derived from the latter. Hughes and Duncan postulated this theory behaviourally within their proposed 1988 model of motivation. This review re–interprets the Hughes and Duncan model to neurochemically describe the motivational development of stereotypic behaviour in the horse.

In the cow, the embryo during the first three weeks of pregnancy is free living in the uterine lumen and is dependent on the maternal glandular secretions for its nutritional support. If the environment is appropriate, the embryo will develop sufficiently to prevent luteolysis. The aim of this study was to investigate the regulation of factors involved in embryonic-endometrial interactions during early pregnancy. Uterine horn sections were collected from 17 pregnant (PREG), 9 inseminated but no embryo present and 10 uninseminated cyclic control cows on days 12, 14, 16 and 18 after natural oestrus. The latter two groups were combined to form a single non-pregnant (NP) group. Trophoblast sections were also collected from the day 14, 16 and 18 embryos. The mRNA for interferon tau (IFNτ), oxytocin receptor (OTR), oestrogen receptor a (ER), prostaglandin G/H synthase -2 (PGHS-2), insulin-like growth factor (IGF) -I and IGF binding protein -1 (IGFBP-1) was determined by in situ hybridisation using 45 mer oligonucleotide probes end-labelled with35 S. The optical density (OD) readings were measured from the resulting autoradiographs. The expression of IFNτ mRNA in the trophodectoderm did not vary with embryo age. The expression of OTR mRNA in the luminal epithelium was first detectable on day 14 in 2 out of 5 NP cows and increased thereafter. Conversely, OTR mRNA was undetectable in all PREG cows except for one day 18 cow. In the NP cows, the first significant increase in ER mRNA concentrations in the luminal epithelium was observed on day 16. The pregnancy had no effect on ER mRNA concentrations in the luminal epithelium on days 12 and 14, but was significantly reduced on day 16 and was undetectable by day 18. On day 18, PGHS-2 mRNA was detectable in the luminal epithelium of all cows, but was unaffected by pregnancy status. The expression of IGF-I mRNA in the subepithelial stroma was maintained from days 12 to 18, but was reduced in the day 18 NP cows. IGFBP-1 mRNA concentrations in the luminal epithelium peaked on day 14 in both NP and PREG cows. Thereafter, concentrations declined in the NP group but were maintained in the PREG animals. In conclusion, the suppression of OTR mRNA expression by the embryo does not appear to require the prior suppression of ER mRNA. The continued expression of IGF-I and IGFBP-1 mRNA is likely to play an important role in the establishment of early pregnancy in the cow.