1. Rapeseed (Brussicu nupus), barley grain, ryegrass (Loliurn perenne) and barley straw were labelled with I5N as an internal marker. The dilution of 15N was used to estimate microbial N (RMNis,) in the feed residues in nylon bags incubated in the rumen for 5, 12 and 24 h. For comparative purposes, diaminopimelic acid (DAP) content of the residues was also determined and rumen microbial N (RMN,,,.,)in the feed residues calculated using DAP as a bacterial marker. The influence of two bag pore sizes (20 pm and 40 pm) with different sample sizes (1 g and 5 g respectively) was also studied.2. For all feeds, the average disappearance of 15N was faster than that of total N, the difference between N and 15N disappearance being marked with barley, ryegrass and barley straw. The disappearance of microbially corrected dry matter (DM; correction calculated from the 15N values) was, accordingly, always faster than the uncorrected D M disappearance. Except for the bag pore/sample size effect for N disappearance, significant (P < 0.01-0.001) feed, pore/sample size and incubation-time effects were always found for the disappearance values.3. Errors (% ) resulting from the microbial contamination (calculated from the 15N values) in N-loss measurement with rapeseed, barley, ryegrass and barley straw, at 5, 12 and 24 h in 20 pm bags were respectively: -1.8, -3.9, -0.9; -3.8, -22.4, -3.8; -7.2, -4.1, -2.9; -164.5, -146.3, -204.6. In 40pm bags the corresponding errors were respectively: -4.4, -1.2, -0.7; -26.1, -10.5, -3.9; -13.2, -6.4, -5 . 5 ; -221.2, 4. The largest residual proportions of RMNis,, RMN,,,., and DAP-N (% of total N ) were found in barley straw, followed by barley, ryegrass and rapeseed, in that order. RMNIs, (g/kg residual DM) followed the descending order: barley, ryegrass, straw, rapeseed. RMN,,,., (g/kg residual DM) and DAP (mg/kg residual DM) followed the descending order: barley, ryegrass, rapeseed and barley straw. Feed, pore/sample size and incubation-time effects were always significant (P < 0,001). 5.With 40 pm bags RMNIs, values of barley, ryegrass and barley straw (expressed as % of total N or g/kg residual DM) were substantially higher than those of RMN,,,.,.With 20 pm bags the RMNi., and RMN,,,., values were generally quite close for these feeds. With rapeseed residues, RMNts, was clearly lower than RMN,,,., with 20 pm bags, but only small differences were found with 40 pm bags. Estimation of feed-protein rumen degradability using the nylon-bag technique (Mehrez & Orskov, 1977) is an attractive alternative to in vivo methods, due to its simplicity and reproducibility. However, as recognized by some workers, the true feed-protein degradation values obtained are probably erroneous due to microbial contamination of the feed residues (Mathers & Aitchison, 1981; Lindberg & Varvikko, 1982;Varvikko et al. 1983; Rooke et al. 1984). Although colonization of feed particles by the rumen microbes has also been demonstrated by several microscopic studies (Akin et al. 1973;Akin & Amos, 1975;Cheng et al. 1977;Baucho...

A review on the nutrient requirements for intestinal growth and metabolism in the developing pig, is presented. Topics include the following: measuring gut nutrient utilization (net portal balance, and utilization of luminal vs. arterial amino acids); metabolic fate of nutrients used by the gut (protein synthesis and amino acid metabolism, nonessential amino acids and glucose oxidation, and essential amino acid oxidation); impact of gut metabolism on whole-body nutrient requirements (effect of reduced gut mass, effect of reduced dietary protein intake, effect of enteric pathogens, and implications for nutrient requirements); and regulation of gut growth.

Summary The objective of the present work was to assess the influence of partial replacement of oats with dried unmolassed sugar beet pulp (SBP) and/or maize oil on nutrient utilisation in horses fed a traditional hay and concentrate diet. The total tract digestibility of nutrients, urinary excretion and plasma parameters were studied in a 4 × 4 Latin‐square design experiment with purebred Arabian geldings. Horses fed the SBP diets responded with a reduced (P<0.05) apparent digestibility of crude protein and feeding of maize oil resulted in an increased (P<0.05) apparent digestibility of crude fat. The apparent energy digestibility was unaffected by the replacement of oats with SBP, but increased (P<0.05) when maize oil replaced part of the oats. The urinary excretion of nitrogen increased (P<0.05) when maize oil replaced oats and the excretion of energy was higher (P<0.05) on the diets where oats were replaced by maize oil and SBP. There was a significant (P<0.05) effect across treatments of postprandial blood sampling time on plasma glucose and insulin concentrations. Also, plasma concentrations of glucose and insulin tended to be higher on the oats than on the SBP diets. In conclusion, the limited effects on the digestibility of nutrients and energy suggest that it should be possible to partially replace oats with maize oil and/or SBP in diets for horses without any impairing effects on the overall nutrient utilisation. However, the dietary‐induced changes in the urinary excretion of energy and on plasma glucose and insulin levels, indicate a possible influence of dietary carbohydrate composition on nutrient utilisation at the organ level, which requires further study.

Abstract. Activity behaviour and social interactions of pigs in indoor and outdoor systems fed different levels of amino acids were studied on 96 crossbred pigs (Hampshire × Swedish Landrace × Swedish Yorkshire). The pigs were born outdoors and raised indoors in conventional pens or outdoors on pastures and given recommended (R), 7 % lower (R-7) or 14 % lower (R-14) levels of amino acids, in a phase feeding system with a low-energy diet provided ad libitum. Pigs in the outdoor system walked significantly more (p=0.012) and tended to be rooting more (p=0.098) than indoor pigs. Amino acid level did not affect the activity behaviour and social interactions of the pigs. Indoor pigs given diets R-7 and R-14 were drinking significantly more often than indoor pigs receiving the R diet, but had less contact with other pigs (p=0.020 and p=0.002, respectively). For outdoor pigs no such effect of amino acid level was found. Queuing for feed decreased with increasing age of the pigs, both indoors and outdoors (p=0.009). Rooting decreased and sleeping increased with the age of indoor pigs (p=0.014 and p=0.001, respectively), whereas no consistent trend for outdoor pigs was found. Sniffing, nibbling, pushing (p=0.001 for all) and tail manipulation (p=0.002) occurred more often indoors than outdoors. The results show that pigs in an outdoor system are more active and perform more natural behaviours, such as foraging and rooting, than pigs in an indoor system. Furthermore, roughages, such as pasture, and large areas may play an important role in occupying pigs and therefore contribute to less aggressive behaviours.

Sallander M, Hedhammar Å, Rundgren M, Lindberg JE: Demographic data of a population of insured Swedish dogs measured in a questionnaire study. Acta vet. scand. 2001, 42, 71-80. -Dogs, in the age range 1-3 years old, were randomly selected from the largest animal insurance database in Sweden for inclusion in the study. The study was performed in 1997, and a total of 680 dog owners were selected for the study. A total of 461 dog owners completed the survey, at an overall response rate of 68%. Data was compared to a recent gallup performed on a sample of all dogs in Sweden. The demographic statistics of the insured dog population were in many aspects similar to the total dog population of Sweden. Typical for both insured dogs and the total population of dogs were a low proportion of neutered dogs, that many dogs were bought at an early age, that many dogs were in contact with a "breeder" when sold, and a similar profile of health status. However, "dog breeders" seemed to have their dogs insured to a higher extent than the general dog owner. It was concluded that as the populations were alike in many respects, it is reasonable to use the insurance database for epidemiological studies on diet and exercise in Swedish dogs.canine; telephone; survey; Sweden.