The potential benefits of mixing leaves containing high and low levels of condensed tannin (CT) on N utilisation in sheep was studied at the Centro Internacional de Agricultura Tropical (CIAT), Colombia.

Supplements of Cratylia argentea (Ca) (tannin free), replaced with 0, 25, 50 or 100% Flemingia macrophylla (Fm) (25.1 g CT/kg DM) were fed as 40% of total ration DM (85g/M0·75), the remainder coming from Brachiaria dictyoneura (Bd). Treatments were offered in a replicated 4x4 latin square to eight male African Hair sheep (mean liveweight 23 (s.e. 1.5) kg), fistulated at the rumen and proximal duodenum (T-piece). Total collections of urine and faeces were used to estimate apparent N retention. Ammonia concentration was measured in rumen liquor samples taken hourly over 24 hours, while duodenal flows were estimated from spot samples using Ytterbium chloride as a single phase marker.

With across-flock genetic evaluations, the extent of genetic links or connectedness between animals in separate flocks affects the reliability of selection decisions. As connectedness improves, error in comparing breeding values among flocks falls. Connectedness is thought more important when founder animals (i.e. unknown parentage) of separate flocks differ genetically. The prediction error variance (PEV) of differences in estimated breeding values (EBV) between animals is considered an appropriate measure of connectedness (Kennedy and Trus, 1993). In this study the level of connectedness, and its consequence, in breeding schemes that differ in the extent of ancestral relationships between flocks, and in which founder animals of these flocks differ genetically, was assessed by stochastic simulation.

This text book was conceived in January 2002, in Tanzania, during a DFID Livestock Production Programme (LPP) workshop. Perceived justifications for such a book were: (1) to improve the preparation of animal science students to address livestock issues faced by resource-poor subsistence farmers in developing countries; the majority of livestock text-books are either a) authored in the ‘north’ and based on temperate, large-scale, commercial systems or b) based on a single species and technology ‘fix’ approach, with insufficient focus on the systems under which livestock are kept by the resource-poor, or on improving livestock survival and productivity and understanding the contribution they make to livelihoods; (2) to address the UN Millennium Development Goal of halving the number of people living in absolute poverty by 2015 through `training teachers’ using appropriate information. Three quarters of poor people live in rural areas and keep livestock; (3) to respond to the large demand for meat and milk over the next 20 years foreseen by the burgeoning ‘Livestock Revolution’ and the consequent opportunities for resource-poor livestock keepers to move from subsistence to a market-oriented economy. The LPP agreed to commission the book provided that consultation with stakeholders confirmed a demand for it and that a broad electorate of stakeholders participated in the book’s design and production. Two editors (E. Owen and T Smith) were appointed to undertake the consultations and subsequent production of the book in collaboration with the Manager of LPP (J.I. Richards).

Computer tomography (CT) scanning is a method for non-invasive imaging of subjects developed for use in human medicine. It allows cross-sectional images, containing a wealth of information, to be obtained for a living animal (Davies et al., 1987). These can be used to provide very accurate assessment of body composition in live animals in a welfare-friendly manner. Not only is accuracy improved but also a wide range of novel traits lend themselves to assessment and objective measurements can be collected rapidly, using mathematical algorithms for image analysis (Glasbey & Robinson, 1999; Glasbey et al., 1999).

The use of body tissue by dairy cows to support lactation is increasing, since selection has led to cows that can eat only around half of their incremental feed requirements per unit increase in genetic merit for milk production (Veerkamp et al., 1995). Continuing with this selection policy is likely to result in increasing use of body tissue to fuel milk production and to lead to thinner cows with associated health and fertility problems. This has created increasing interest in body condition scoring (CS) in dairy cows as both an important management tool and also for use in selection indices. The ability to automatically record CS would increase the use of this measure in farm management and enable large volumes of data to be collected for use in national evaluations.

It is estimated that ammonia emission from pigs contributes approximately 23kt of a total of 198kt from UK agriculture. Of this, 14kt is lost from buildings and 7.5kt from land spreading. It is likely that pig enterprises will need to reduce ammonia losses under the newly adopted Integrated Pollution Prevention Control (IPPC) legislation. Earlier work (Kay and Lee, 1996) has demonstrated that low crude protein (CP) diets reduce the amount of nitrogen in slurry. However, there is no information available on the effects of reducing nitrogen excretion by pigs on the emission of ammonia from buildings and limited information on the effects of collection and storage of slurry over time. The objective of this experiment was to determine the effect of low CP diets on the emission of ammonia from buildings, and on the characteristics of slurry collected and stored beneath slats.

Prolactin plays an important regulatory function in mammary gland development, milk secretion, and expression of milk protein genes. Hence the PRL gene is a potential genetic marker of production traits in dairy cattle. The gene was mapped on chromosome 23 by Hallerman et al. (1988). It consists of 5 exons and four introns (Camper et al. 1984) encoding the 199-amino-acid mature protein (Wallis 1974). On the basis of sequence analysis of four different cDNA clones, seven possible nucleotide substitutions were described by Sasavage et al. (1982). One of them, recognized by RsaI endonuclease, has become a popular genetic marker used for genetic characterization of cattle populations by means of PCR-RFLP (Mitra et al., 1995). Two allelic variants (B and b) have been distinguished at the DNA level, based on RsaI polymorphism in the third exon of the coding region. It has been suggested that prolactin alleles correlate with milk yield (Lewin et al., 1992).

Animals are an object of concern, and, as we extend our control over the earth’s resources, ever more so.

The old way of distinguishing humans from other animals - in terms of the soul, God’s purpose, and the after-life - is no longer universally accepted, and the Darwinian theory of species has unsettled people’s moral perceptions. Is there any way of making the distinction between humans and other animals, therefore, that could recommend itself to modern, secular, sceptical people who believe nevertheless in the difference between right and wrong?

N-alkanes are components of plant cuticular wax which have been successfully used as markers for the estimation of grass intake and digestibility in grazing ruminants (Dove and Mayes, 1991). Natural n-alkanes are predominately odd chain, and a known dose of an artificial even chain n-alkane (normally c32 or c36) is used to enable intake to be measured. Dietary n-alkanes may behave differently in the gastro-intestinal tract of ruminants and non-ruminants (Mayes et al, 1995). Therefore, in order to utilise this methodology in studies of outdoor pigs, this experiment was carried out to validate the faecal recovery of n-alkanes in this species. Since n-alkanes are soluble in lipid, which is often incorporated at high inclusion levels in pig diets, the experiment was also designed to determine whether n-alkane recovery is influenced by dietary lipid content.

The UK is bound by the UN Framework Convention on climate change to reduce methane emissions to below 1990 levels by the year 2000. The Kyoto protocol requires a further cut of 12.5% by 2010. Ruminants are estimated to produce 74 Tg of methane per year (Benchar et al. 1998) which represents about 15% of total emissions (Crutzen et al., 1986). Therefore any reduction in the release of methane gas by enteric fermentation from the dairy herd is environmentally important. The objective of this study was to use data obtained from calorimetry trials to generate multiple regression equations predicting the levels and variability of methane emissions from dairy cows.

Concerns regarding levels of fat consumption and particularly saturated fatty acids (FA) (Department of Health, 1994), has resulted in closer scrutiny of the FA composition of ruminant products. The FAs deposited in beef tissues are relatively saturated, leading to a low polyunsaturated:saturated FA ratio (P:S) in the meat (approximately 0.1, the ideal being about 0.4), whilst the n-6:n-3 ratio is beneficially low at approximately 2. Feeding strategies for raising the P:S ratio whilst keeping n-6:n-3 ratio low are required. This experiment has investigated the impact of feeding different sources of long chain polyunsaturated FA (PUFA) on animal performance and the FA composition of muscle.

The gain in genetic merit for milk production in the US (Foote, 1996) has been accompanied by a decline in conception to first service of approximately 0.45% per year (between 1975-1997, Butler and Smith, 1989; Beam and Butler, 1998). A similar trend is anticipated in the UK. Lamming and Darwash (1998) reported that defective ovarian function prior to insemination contributes to lower reproductive efficiency. In particular, persistent luteal activity was associated with reduced fertility and a higher incidence of late embryo mortality (embryonic death after day 16 post-insemination). The objectives of this study are firstly, to determine the current incidence of atypical ovarian hormone patterns and secondly, to make specific comparisons between the present results and those of our previous study.

One way of testing cognitive abilities (or intelligence”) is by using so-called “means-end” tests, where the desired outcome can only be achieved by utilising some means to that end. Pulling a piece of food that is out of reach into reach with the help of an attached string is one of these means-end tasks. The ability of dogs to solve this problem has so far been only tested in 4 studies, all from the 1930s and 40s, with a total of 11 dogs and varying success. Additionally to exploring this basic cognitive ability in pet dogs the study explored whether training, and in particular so-called Clicker training (operant conditioning with secondary reinforcer), had an influence on the performance in this task.

Some studies with beef cattle have shown that breed and diet affect tissue fatty acid composition and meat quality (Choi et al., 2000; Scollan et al., 2001). However, the effects of breed are often confounded with differences in growth rate and body composition. Diet also affects fatty acid composition, however, feed composition studies are often confounded by the use of mixed diets and few have compared all-forage with all-concentrate diets. This study, therefore, was designed to compare Aberdeen Angus and Holstein-Friesian breeds growing at similar rates and fed either all-forage or a high concentrate diet.

It has been shown that horses and ponies at pasture usually graze for 15-17 hours per day, and consume between 16 and 33g dry matter (DM) /kg live weight per day, depending on animal size and physiological status. However, many predominantly stabled horses have restricted access to pasture, often only 1-3 hours/day. There is no information on voluntary food intake (VFI) of horses under such regimens. Therefore the aim of this pilot study was to determine the voluntary intake of fresh herbage by ponies when their access to pasture was restricted.

The amount of a bulky food that an animal can eat depends on its capacity for bulk and the bulk content of the food. For pigs between 12 and 40kg the capacity for food bulk was found to be directly proportional to liveweight (Kyriazakis and Emmans, 1995). The way in which the capacity for bulky foods changes with weight above 40 kg is not clear; there is no a priori reason to assume that the scaling rule proposed for young pigs will hold in heavier pigs. The applicability of the work in young pigs for use in more mature pigs needs investigation, to develop predictive equations for the whole relevant weight range. An experiment was designed to determine how the capacity for bulk changed with weight; the objective was to develop a relationship between the capacity for food bulk and liveweight.

One of the major limitations to increasing the polyunsaturated fatty acid (FA) composition of ruminant products is the fact that these FAs tend to get hydrogenated by rumen micro-organisms to more saturated end products (biohydrogenation). This experiment reports on the extent of FA biohydrogenation in the rumen of four diets of differing sources of long chain polyunsaturated FA (PUFA) as used by Scollan et al. (1997).

Standards for organic pig production recommend that growing pigs are maintained on pasture. There is currently no information on the nutritional implications of such a system, since grazing intakes have not been recorded in pigs of this production stage. This study used n-alkane methodology previously validated in sows (Wilson et al., 1999) to measure the herbage intakes of individual pigs under such conditions.

Harmful social behaviour is behaviour that is directed at pen mates which, if persistent, causes injury. It includes tail, ear and flank biting. The aim of this work was to determine if pigs that are predisposed to harmful social behaviour can be identified early in life using a test. In this experiment a test that measured the chewing behaviour of pigs on an artificial tail was developed from Fraser (1987), as one of a wider battery of tests under investigation in the overall project. The validity of the test was evaluated by correlating the rope directed behaviour in the test with harmful social behaviour in the home pen.

Previous studies have demonstrated that including fish oil (FO) in the diet of beef cattle resulted in increased long chain C20n -3 PUFA (20:5n -3 and 22:6n -3) in muscle resulting in a lower n -6:n -3 ratio (Scollan et al., 2001). However, it may result in negative effects on colour shelf life and organoleptic properties (Vatansever et al., 2000). Fish oil is also a good inhibitor of biohydrogenation in the rumen, resulting in increased production of 18:1trans (TVA), the precursor for conjugated linoleic acid (CLA cis -9, trans -11) in muscle. This study investigated the effects of incremental levels of fish oil in the diet on the fatty acid composition of the m. longissimus dorsi and meat quality.