Maize distillers grains (MDG) are a traceable and valuable energy and protein feed for dairy cows (Owen and Larson, 1991) but little is known about the ability of UK MDG to replace more conventional protein sources, particularly their effects on the supply of protein to the cow. The purpose of the present experiment was to examine the effects of replacing soyabean meal with MDG on digestion in the rumen and flow of protein to the duodenum of lactating dairy cows.

Forage trees are commonly used in the tropics as supplementary feed for ruminants. However, during the dry season where grass is of poor quality, many trees also shed their leaves and are no longer available. Adequate strategies are to be evaluated to allow forage trees to be introduced into feeding systems as good quality supplements along the year. Silage might be an adequate technology if the resultant product allow similar animal performance as those achieved using commercial concentrate as supplement, but few studies have been conducted with forage tree silages. The objective of the present experiment was to evaluate intake, digestibility and microbial-N synthesis of diets supplemented with grains or forage tree silage.

In pasture-based dairying systems it is important to maintain a 365-day calving interval, which requires that cows have a rapid resumption of postpartum ovulatory activity and high conception rates. The major form of infertility in New Zealand (NZ) dairy cows is an extended postpartum anovulatory interval (ppai; Macmillan, 2002), a problem that can be exacerbated by low body condition score (BCS) at calving (McDougall, 1995). Furthermore, Holstein cows, originating from North American genetic strains (Overseas; OS), which have been widely used in NZ in recent years, have longer intervals to first mating and conceive later than do NZ strains, suggesting a possible delay in the initiation of postpartum cyclicity (Harris and Winkleman, 2000). Worldwide, there is concern over an apparent decline in the fertility of Holstein-Friesian dairy cattle (Butler et al., 1995; Royal et al., 2000). The purpose of this trial was to determine whether there was a difference in ppai and BCS between NZ and OS Holstein Friesians that may affect reproductive performance.

Carcass fat of meat producing animals has long been identified as one of the most important characteristics of overall meat quality. In this respect, consumer choices of particular food reflect their awareness of the link between health and consumption of fats particularly saturated. Lamb meat is considered to be excessively fat and this results in substantial loss in its marketability. This study was carried out to assess the effect of breed, sex, post-weaning nutrition, live weight at slaughter and their interactions on the fatty acid (FA) composition in carcass fat of lambs of three indigenous dairy Greek breeds of sheep.

The success of sheep breeding programmes involving sire reference schemes depends on effective oestrous synchronisation programmes that provide optimum pregnancy rates following fixed-time insemination (McKelvey & Simm, 1995). Effective oestrous synchronisation is characterised by low progesterone concentrations at the time of insemination. However in pedigree Suffolk ewes inseminated at a synchronised oestrus in early August, Dingwall et al (1995) reported that a significant number of ewes in some flocks had elevated progesterone concentrations at the time of insemination and, as a consequence, flock fertility was adversely affected. It is hypothesised that high progesterone reflects aberrant luteal activity arising from spontaneous ovulations following the preceding lambing. The present study sought to identify the incidence of aberrant luteal activity in Suffolk ewes during seasonal anoestrus and to study the effect on conception of interventional treatment of these animals prior to artificial insemination.

Several studies with barley straw (e.g. Wahed et al, 1990) and sorghum stover (e.g. Osafo, 1993) have shown improvements in intake with increasing ‘ad libitum’ amounts offered. Furthermore, these studies have demonstrated that sheep and goats offered barley straw or sorghum stover in long, unprocessed form, increase intake by selecting for leaf and leaf sheath, and against stem. This phenomenon offers a simple feeding strategy to use selective feeding behaviour to improve intake and hence production. The aim of the present experiment was to study the effect of offering increasing amounts of long maize stover on intake and selection by dairy cows.

Six, early- to mid-lactation Ayrshire and Friesian cows (live weight, M, 430 kg) were used in a double 3x3 Latin square design with 24-day (d) feeding periods. Cows were offered long (unchopped) maize stover at low, medium or high ‘ad libitum’ rates, i.e. 31, 59 or 87 g dry matter (DM)/kg M.d. Cows also received 3.2 kg DM/d of cotton seed cake (339 g/kg DM crude protein) in two meals at milking (0700 h and 1800 h). Stover was offered in one meal daily, at 0700 h, after collecting refusals from the previous day. Amounts of stover offered and refused were weighed daily. Samples of offered stover (0.5 kg) and refused stover (0.5 kg) were analysed for DM daily. All refused stover and 4.0 kg samples of offered stover were botanically fractionated, daily, into stem (S), leaf (L), sheath (Sh) and husk (H). Milk yield was recorded daily and cows weighed at the start and end of each period.

Veerkamp et al. (1998) make the case for including somatic cell count (SCC) in the index of total economic merit (ITEM, Veerkamp et al., 1995) used to rank dairy bulls and cows in the UK for breeding purposes. They go on to describe an empirical method to obtain a suitable economic value for SCC, reflecting the milk quality payment scheme. Since this work was carried out, the milk price has fallen while price penalties against SCC have risen. Bulk-tank SCC (BTSCC) has fallen in response. Some of this improvement may be due to culling cows with high cell counts. The objective of this work was therefore to establish an economic value for somatic cell counts which reflected the milk quality payment scheme and took into account culling strategy.

Ovulation rate (OR) is depended to energy intake level (EIL) and body condition score (BCS) in ewe (Gordon, 1997). There is a high correlation between BCS and plasma leptin concentration (PLC) in sheep (Blache et al, 2000). Corresponding to leptin is a metabolic stimulant for reproduction (Barb et al, 1999), it is possible that leptin is involved in the ovulation rate in ewe. Therefore, first experiment was conducted to study the effect of EIL on body weight (BW), BCS, OR and PLC in a long period, and second experiment was designed to investigate the effect of EIL and leptin administration on OR in a short period in fat-tailed Shal ewes.

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.

In a previous experiment with dairy cows at this Institute, in which fodder beet was included as a third component of the diet along with grass silage and concentrate, fodder beet considerably increased metabolisable energy intake (MEI), but there was little effect on milk yield (unpublished data). The main objectives of the present study were to examine the effects of including fodder beet versus concentrate in a grass silage diet, on milk production, digestibility of nutrients and the utilization of nitrogen (N) and energy at equal ME intake in lactating dairy cattle.

The standard recommendation for grazing cows to be given 60g calcined magnesite (c. 30 g Mg /day) seems large relative to the ARC (1980) dietary Mg allowance (0.17 coefficient of Mg absorption in the whole diet) of 32.6 g for 30 kg/day milk yield. ARC (1980) estimated the coefficient of absorption of calcined magnesite could be 0.05-0.10 and indicated that supplementary magnesium sources should be readily soluble in rumen liquor. Both temperature of calcination and particle size markedly influence rumen solubility and apparent Mg availability of calcined magnesite (Adam et al. 1996). Magnesium hydroxide powder (H, 404 g Mg/kg) is very finely divided (970 g/kg < 20 μm of which 870 g/kg is < 6um and with 200 g/kg < l μm diameter and is manufactured on a large scale (Redland Minerals, Hartlepool TS24 0BY). ‘Granular’ calcined magnesites are screened to < c. 2000μm diam.

The furnished cage for laying hens is one attempt to meet the welfare problem of behavioural restriction in conventional battery cages. However despite the presence of a dustbath, sham dustbathing on the cage floor, which is usually associated with litter deprivation, is often seen. It has been suggested that the performance of sham dustbathing is satisfying enough to substitute for dustbathing in litter (Lindberg & Nicol, 1997) but later experimental studies have failed to show that it reduces the motivation to dustbathe in litter (Lindberg, 1999; Olsson et al, accepted). An alternative hypothesis is that sham dustbathing is a consequence of social competition since the dustbath is not big enough to allow all birds in a cage to use it at the same time. If this hypothesis is true, sham dustbathing would be expected to take place mainly when the dustbath is occupied. We tested the hypothesis by observing sham dustbathing and the use of dustbaths in furnished cages.

It has been suggested for many years that inclusion of fishmeal in diets for breeding sows gives improved reproductive performance, but there have been few experiments to objectively measure the effects of fishmeal inclusion. Recently, attention has focussed in many species on the possible beneficial effects of the long chain omega-3 fatty acids contained in fish oil on a number of aspects of reproduction, including embryo survival, gestation length, fetal growth and neonatal viability. This experiment was therefore carried out to measure the effect of feeding diets with or without inclusion of fishmeal with a high content of omega-3 fatty acids on sow reproductive performance.

Sainfoin (Onobrychis viciifolia) is a Mediterranean forage rich in tannins, which has been shown to reduce the faecal excretion of nematode parasites in goats, when offered as hay supplement (Paolini et al, 2003). The use of conserved forages for parasite control may be preferred when either the climatic or agronomic conditions are not appropriate for the grazing of such forages. The aim of this experiment was to investigate whether the consumption of sainfoin hay could reduce the viability and fecundity of adult gastrointestinal parasites, when offered to parasitised sheep at different time points during the course of a parasitic challenge.

Perinatal lamb mortality can account for up to 20% of annual lamb losses, and at least a third of these deaths can be attributed to maternal factors (Mellor, 1988). Improvement in the quality of maternal behaviour may, therefore, lead to a reduction in lamb deaths. In order to identify if there is a genetic component to the expression of maternal behaviour, the behaviour of a lowland (Suffolk) and a hill (Scottish Blackface) breed of parturient ewe were quantified after the birth of a single lamb.

In Iran various varieties of sorghum (Sorghum vulgare) are planted mainly for broom production but also for use in animal nutrition. There appears to be no documented research about nutritive value of microwave processed sorghum grain. With microwave irradiation, heat is generated throughout the material, leading to faster heating rates and shorter processing times compared to conventional heating, where heat is usually transferred from the surface to the interior (Fakhouri and Ramaswamy, 1993). In the in vitro gas production method for predicting nutritive value, the kinetics of fermentation can be studied on a single sample and therefore a relatively small amount of sample is required or a larger number of samples can be evaluated at any one time. Gas production measurement provides useful data on digestion kinetics of both soluble and insoluble fractions of feedstuffs (Getachew et al., 1998). The purpose of this study was to evaluate effects of microwave irradiation on nutritive value of broom sorghum grain using the in vitro gas production technique.

Most functions used to describe the lactation curve of dairy animals are empirical in approach and result in parameters with little or no biological meaning. A new model for describing lactation based on the biology of the pregnant and lactating animal is proposed and compared to several empirical models (Wood, 1967; Grossman and Koops, 1988; Morant and Gnanasakthy, 1989).

Lactation is thought of as the balance between an increase in secretory cell numbers (NSCP) and their later decline (NSCD). The difference between them is the number of active secretory cells, each of which secretes milk at a particular rate (S kg/cell/day). Thus daily milk yield (MY) = (NSCP – NSCD) x S.

Increasing maturity at harvest of maize silage has been shown to affect feed intake and milk production in Holstein-Friesian cows (Phipps et al., 1998). The purpose of the present experiment was to determine whether the milk production response was related to improvements in the efficiency of feed energy utilisation.

Four multiparous Holstein-Friesian cows (mean live weight 620 kg) fitted with permanent cannulas in the rumen and proximal duodenum were given diets based on maize silage and grass silage (3:1 DM ratio) offered ad libitum plus 8.7 kg DM/day of a concentrate (254 g crude protein (CP)/kg DM) starting 5-10 weeks post-calving. The maize silage was harvested at four different stages of maturity as defined by DM content and ensiled without additives. The grass silage was a first-cut perennial ryegrass (260 g DM/kg, 519 g neutral detergent fibre (NDF)/kg DM, 146 g CP/kg DM).

Polychlorinated biphenyls (PCB) are persistent environmental contaminants that have been reported to adversely affect reproduction in mammals. The exact mechanism of action of these chemicals on oocyte and embryo development are not known. Previous studies in our laboratory demonstrated that PCB adversely affect in vitro oocyte maturation and embryo development in two different in vitro systems (cattle, rabbit). The objective of present study was to investigate the possible role of the arylhydrocarbon receptor (AhR) in PCB toxicity. The AhR is a transcription factor activated by ligands such as dioxins or PCB. Its transcriptional activity depends on dimerisation with its nuclear partner ARNT. The presence of AhR and ARNT was investigated in bovine and rabbit genital tract (uterus, ovary) and embryonic tissues, employing RT-PCR and immunohistochemistry.

Human intervention and selection of sheep for production characteristics have led to the establishment of defined breeds adapted to live in diverse environmental conditions. It is also apparent that the social and foraging behaviour of different breeds can vary considerably (Arnold, 1985; Dwyer and Lawrence, 1996), even within the same environment, and variations in social behaviour may have significant effects on production (Lawrence and Wood-Gush, 1988). It remains to be established, however, whether these behavioural differences have a genetic basis, or result from the cultural transmission of information and learned behaviour. The aim of this study was to examine the effects of ewe genotype and behaviour on the behaviour of lambs of different breeds derived by embryo-transfer.