As a result of the need to excrete the waste products of protein catabolism in urine, increases in protein intake have been associated with increases in water intake in poultry (Bailey, 1990), in pigs (Brooks and Carpenter, 1990) and in ruminants (Agricultural Research Council, 1980). Whilst there is only very limited data available to support a similar relationship in horses (Meyer, 1987) it is believed that increases in protein intake in equines also result in greater water consumption when high protein diets are fed (Lawrence, 1998). The objective of the current study was to examine the relationship between crude protein intake and water consumption when forage based diets were offered ad libitum to individually fed ponies. Six mature Welsh–cross pony geldings with a mean liveweight (LW) of 281 kg (s.e.d. 0.89) were individually housed in pens bedded with wood shavings and used in a changeover design experiment consisting of two 21-day periods.

Six mature Welsh-cross pony geldings with a mean liveweight (LW) of 281 kg (s.e.d. 0.89) were individually housed in pens bedded with wood shavings and used in a changeover design experiment consisting of two 21-day periods.

Current pig production systems reflect management decisions taken over a period of many years. The range of constraints on pig producers has grown rapidly and priorities are in the process of change. On the basis of the available evidence, the following conclusions may be made.

Less than half the pig breeding enterprises in the United Kingdom use sow housing which involves individual confinement and more than half provide dry sows with bedding. At present, there is a strong current interest in group housing systems.

In the parturition and lactating stages, farrowing crates are used in the vast majority of herds and the main current practical interest is in improving crate and pen design and husbandry techniques to assist in minimizing piglet mortality.

Less than half of the herds use fully slatted accommodation for newly weaned pigs and nearly one-third provide bedding. In the follow-on stage, less than one-fifth of herds use fully slatted floors and ‘fully controlled environment’ type accommodation.

There is strong current interest in fully slatted finishing housing but so far less than one-tenth of herds use it. Nearly two-thirds of herds use finisher houses which are not in the ‘controlled environment’ category.

In recent years, it has become clear that the amount and type of protein included in diets for dairy cows are crucial factors determining milk production. On many occasions, milk production has been increased by increasing the protein content of the diet. On rather fewer occasions, milk production has been altered by changing the source of dietary protein. However, in all instances, it has been inferred that the milk production response is related to changes in the amounts of total amino acids reaching the small intestine.

No account has previously been taken of the extent to which these changes in milk production, consequent on changing protein inputs, depend on the nature of the basal diet although it is well established that the nature of diets, in particular their influence on the balance of fermentation end-products produced within the rumen, has a big influence on the partition of nutrient use between secretion in milk and deposition in tissue. This experiment was designed to measure the response of dairy cows to protein supplements given with diets designed to maintain widely different patterns of rumen fermentation.

The need to assess the adequacy of nutrition arises frequently. It occurs in relation to individual animals and to groups of animals in both experimental situations and in commercial practice.

The measurement of food intake poses certain difficulties and involves a considerable amount of time and effort, particularly with grazing animals, but also with housed animals which are group–fed. Even where food intakes can be measured, the assessment of the adequacy of that nutrition necessitates a knowledge of the animal's requirements – and this too can present problems in some situations. Changes in live weight and in body condition are obvious and useful indices of the adequacy of nutrition, but in many cases the time taken for such changes to become manifest is too great. By the time an excessive rate of live–weight loss has been detected it may be either too late to effect a change in the level of feeding, or an unacceptable production penalty may have already been incurred.

The preceding paper has detailed our current understanding of the processes of N digestion in the ruminant animal as they relate to the events occurring within the reticulo-rumen. It is the purpose of this paper to consider the processes of digestion occurring principally within the small intestine and to comment on the significance of events occurring within the caecum and colon in so far as they relate to nitrogen digestion. The fate of amino acids subsequent to their absorption from the gastro-intestinal tract will also be discussed, in particular the way they are catabolized and whether this limits their availability for the synthesis of protein. Reference will also be made to purine and pyrimidine nitrogen; these products arise from the considerable content of nucleic acids in the microbial mass which leaves the reticulo-rumen and undergoes digestion in the small intestine.

Neutrophils perform a series of sequential functions to kill pathogens entering the body. The objective of this study was to investigate whether variation across cows in neutrophil function tests is related to milk production and energy balance. Blood samples from 37 Holstein-Friesian heifers were taken early morning after milking and prior to feeding. Each cow was sampled about 30 days before calving and at 30 and 100 days after calving. Three groups of neutrophil function tests were used: (i) measurement of phagocytosis of bacteria (with heat inactivated serum (no complement) or complete serum (complement and antibodies)); (ii) measuring production of reactive oxygen species (ROS) with 30, 100 or 300 nmol/l phorbol myristate acetate (PMA); and (iii) after ingestion of bacteria (Staphylococcus or Streptococcus). Milk production (including fat, protein and lactose percentage), live weight and food intake were recorded for the first 100 days of lactation and blood metabolic concentrations (non-esterified fatty acid, glucose, beta-hydroxybutyrate) were measured fortnightly (six samples per cow). Restricted maximum likelihood was used to estimate the regression coefficients of neutrophil function on these traits and cow identity was fitted as random effect to account for the repeated measurements. There was no effect of milk yield on the neutrophil function but animals with a higher food intake and a more positive energy balance had a lower ROS production across the lactation (PMA). Of the metabolic characteristics, (beta hydroxybutyrate was positively associated with the capacity of reactive oxygen species production (significantly for 300 nmol/l PMA and close to significant for 100 nmol/l PMA; P < 0.05) but negatively with reactive oxygen species after ingestion of bacteria. Hence, results from these two reactive oxygen species tests contradict each other. The results suggest that immune function is not affected by selection for milk yield, as long as food intake capacity is increased sufficiently.

The liver is important in the homeostatic regulation of manganese (Mn) and copper (Cu). The rates at which the liver removes these trace elements from plasma and excretes them in bile have been measured by using either cattle in which the duodenum had been surgically modified to allow bile to be sampled and its rate of flow measured, or cattle with cannulae in hepatic, portal, mesenteric and carotid vessels.

Livestock make a significant contribution to the world's supply of protein and energy. They occupy dry and cold areas where crop farming is not possible, as well as integrating with crops in warmer, wetter zones. In developing countries they play a major part in household dynamics and family social status. This implies that they should be given serious consideration when agricultural research agendas are set and resources allocated. This paper examines some of the processes used for research priority setting and comments on the likely impact of these processes in setting research agendas for livestock. One case study is considered in detail, that of the Kenya Agricultural Research Institute (KARI).

Methods for prioritization of research range from the very informal, where priorities are determined by discussion in small expert groups, to the comparatively formal and quantitative estimation of economic surpluses. Between those extremes are a variety of methodologies for selecting and ranking research programmes and projects. In a liberalized economy, market forces will play a large part in determining the research agenda; in a centrally planned economy, the national research agenda will be determined by the government, although the trend is towards focusing on the needs of the end user. No one method can guarantee results, since effective research prioritization depends on accurate prediction of future demand. All methods have a degree of subjectivity and may be biased by the selection of stakeholders involved in the debate.

This paper proposes that more rigorous methodology will tend to make results more objective, more transparent and by introducing an explicit market orientation will facilitate the transition from central planning to competitive bidding, but users of any method should be aware of its limitations. The economic surplus method, possibly the most rigorous currently available for setting a national research agenda, is limited by thefact that it does not require measures of social or environmental impact, and to include these requires an additional weighting process. Any trend towards methodological rigour, whether quantitative or qualitative, has costs in terms of data gathering, time and the necessary training to carry out the analyses.

KARI has over the last 10 years moved through the full spectrum of priority-setting methods from informal to formal. It is at present engaged in setting priorities for the next 5-year span, using an economic surplus approach. Some of its experiences and lessons are described in this paper, with particular reference to livestock programmes. The authors conclude that a systematic process of setting research agendas will, on the whole, be favourable to livestock. There has in some cases been a tendency to exclude them because they are harder to work with than annual crops, research can be more costly, their value is harder to estimate and benefits take longer to accrue. A rigorous process of’ estimating benefits from research, with a reasonably long time horizon, should provide a realistic assessment of the value of livestock to an economy and is likely to encourage investment in livestock research.

In the traditional silvo–pastoral system, Alentejano pigs are fattened with acorns and pasture. Although this production system (“Montanheira”) has been characterised, there is a lack of knowledge on intake and digestibility of the diet, mainly due to the absence of tested methodologies in pigs. The n–alkane technique, extensively used in ruminants to estimate diet intake and digestibilitiy, has had less use in pigs. The objective of this experiment was to validate the n–alkane technique in Alentejano pigs. Faecal recoveries of natural and dosed n-alkanes, the diurnal variation of faecal n–alkane concentration, and the time span required to reach a steady state excretion of dosed alkanes were determined. Eight male Alentejano pigs (54.4±9.8 kg LW) were randomly allocated to two groups and placed in metabolic cages. They were fed 0.7 kg of pasture and 0.7kg of ground acorns daily as two meals. Pigs in Group-1 were given once daily artificial C32 (40mg/d) and C36 (40 mg/d) and those in Group-2 the same alkanes as two daily doses of 20 mg. Steady state excretion of both alkanes was reached 3 days after first dosing. Although no difference (P>0.05) was observed between treatments, the coefficient of variation of feacal alkane concentration when dosed twice daily was generally lower than when dosed once daily. Mean faecal recoveries of n–alkanes increased with increasing carbon-chain length (C25 to C36) from 38 to 69%, but were not significantly different from C29, C32, C33 and C36 (mean 0.694 SEM 0.067). Faecal nalkanes in samples collected every four hours for three days showed no diurnal variation in patterns of excretion apart from a higher concentration of C32 4 hours after dosing once daily. However variation between animals was lower when artificial alkanes were dosed twice daily than when once daily. The results indicate that the n–alkane techique may be used to estimate intake and digestibility under “Montanheira”, although further validation work needs to be done.

The ‘gas test’ technique (Menke and Steingass, 1988) is becoming popular for predicting the feeding value of forages. However the relationships observed by Khazaal et al. (1995) between in vivo data and prediction measurements on grasses and legume hays were less good with the gas test technique than with the in situ technique. The present results are part of the work undertaken at the laboratory with the aim of improving the accuracy of the technique on various types of foods (Chenost et al., 1997).

Seventy-nine forages (24 green (G) grasses, 38 grass hays (H), five G lucernes and 12 lucerne H) of known in vivo organic matter apparent digestibility (OMD) out of which 45 (17 G grasses, 16 grass H, five G lucernes and seven lucerne H) of known voluntary dry-matter intake (DMI), both measured with sheep, were chosen based on the range of variation of their OMD (from 0-490 to 0-808) and of their crude protein content (CP from 48 to 253 g/kg DM).

The relationship between body condition at calving, uterine tone and discharge, time to first oestrus and changes in concentration of serum calcium and magnesium in early post partum was examined in 209 multiparous dairy cows located in four herds in the San Joaquin Valley of California. Body condition score (BCS) was graded from 0 to 5 and BCS at calving was estimated from BCS in the late dry period (LDBCS). Uterine tone and discharge were graded from l(best) to 3(worst) after rectal palpation at two weeks post partum. Concentrations of blood metabolites and levels of progesterone were determined from blood samples taken at selected stages of lactation from the late dry period to ten weeks post partum. Abnormal uterine discharges were strongly correlated with uterine tone. Uterine tone and discharge scores were significantly lower in cows that calved with body condition scores of 2.5 and 3.0 than in those which calved with body condition scores of < 2.5 and ≥ 3.5. Serum calcium and magnesium concentrations were higher at two weeks post partum in cows with scores of 2.5 and 3 than in cows with higher or lower scores. Serum calcium and magnesium concentrations appeared to be higher with decrease in grades of uterine discharge and tone but this was significant only in the case of serum calcium and uterine discharge. The number of days to first oestrus was significantly associated with uterine discharge and tone (P < 0.05) but not significantly associated with LDBCS. The number of days to second oestrus was not significantly associated with uterine discharge and tone but was significantly less in cows with LDBCS 3 (17.28 days) than cows with lower or higher LDBCS (P < 0.05). It is concluded that body condition at calving is associated with serum micromineral balance and subsequent uterine and ovarian health. Based on these measurable indicators, cows calving with body condition scores of 2.5 and 3 appeared to be in optimum condition for post partum reproductive performance.

The chemical composition and processing characteristics of milks from spring and autumn calving herds were investigated to establish if an autumn/winter milk supply would overcome the variation in composition and quality which is characteristic of a seasonal milk supply. Three herds of 26 cows were established with mean calving dates of 22 February, 28 September and a 50:50 combination of both. The experimental period was from 5 August to 22 December. Bulk milks were collected separately from each of the three herds at one consecutive am and pm milking each week. Spring and autumn milks were also bulked in proportions of 70:30, 50:50 and 30:70, respectively. All milks were analysed for gross composition, protein fractions, renneting properties (rennet coagulation time [RCT], rate of curd aggregation [K20] and curd firmness [A60]), free fatty acids (FFA) and somatic cell count (SCC). Total protein and casein of spring milk were reduced (P<0.001) from 38.1 and 28.7 g/kg, respectively in the period 14 October-24 November to 33.8 and 25.9 g/kg in the period 25 November-22 December. This was accompanied by a deterioration (minimum P<0.01) in RCT from 21.7 to 33.3 min, in K20 from 8.2 to 15.2 min and in A60 from 43.8 to 30.8 mm. Autumn milk had higher fat (P<0.01) and lactose (P<0.001) concentrations, lower FFA levels (P<0.001), improved (P<0.001) RCT, K20 and A60 values compared to spring milk in the period 25 November-22 December. During this period, the 70:30 milk had improved RCT (P<0.01) and K20 (P<0.05) values and reduced (P<0.01) FFA levels compared to spring milk. It is concluded that the composition and processing characteristics of spring milk deteriorated after 275 days in milk. Changes in total protein and casein were closely associated with changes in renneting properties. Blending of autumn milk with spring milk improved the processing characteristics of the mix compared to those of spring milk. Thus, the introduction of early lactation autumn milk at the end of the spring lactation would maintain good milk processability and allow continuous product manufacture.

This paper describes the steps that were taken to increase the productivity of a commercial cheese company by genetically altering the milk composition. These steps included validation of the effect of b–lactoglobulin polymorphism on casein production and cheese yield under typical New Zealand pastoral farming conditions, manufacture and ripening of cheese from single variant milks, selection of a suitable company to trial breeding for a single variant, development of a suitable payment scheme to reflect the additional value of the higher casein milk, development of a testing regime to support the payment system and getting buy–in from the company. These steps have all been taken, and the company has pursued the recommended breeding strategy for 3 years, purchased instrumentation and elected to move to the new testing and payment scheme for the current dairy season.