| Popis: |
The effects of including fibrous ingredients in the diet of the lactating sow and the growing pig have been examined. Additionally, an attempt was made to obtain some information about the nature of the body tissue losses in sows following weaning. 1. The lactating sow: The fibrous ingredient included in the diet was either oat husks or barley straw. Two such diets containing 40% ground oat husks (OH) or 30% ground straw (ST) were compared with a conventional restricted control (c) in a 7 week lactation, using 24 sows (8 sows per treatment) in a randomised block experiment. The differences in daily dry matter intake between any two treatments were significant. There were no significant differences between treatments in number of piglets per litter, mean weight of piglets and total gain of litters either at 21 days of lactation or at loaning. However, piglets of sows fed diet (ST) had a higher creep consumption but not significantly so. Sows which gained weight during lactation, tended to lose more weight in the period between weaning and one week later but the differences were not significant. The milk yield of 4 sows per treatment was measured at 14 and 20 day of lactation by weighing the litters before and after suckling at hourly intervals, while milk composition was studied in samples taken at 15 and 21 day using oxytocin. There were no significant differences in either milk yield or composition. However, the fat content of milk tended to be higher for sows fed the two fibrous diets, but it varied considerably between sows on diet OH and the differences failed to reach significance. The digestibility of the dietary components was studied between 15 and 20 day of lactation, utilising 4 sows from each treatment. The rate of passage of diet through the gut was significantly faster than the other two diets, which were similar for this characteristic. 2. The newly weaned sow: The main object of this study was to measure in sows the loss in body water in the week following weaning. Measurements were made by the deuterium oxide dilution technique, following an overnight fast, one day and 8 days post weaning. Two diets were given to four pairs of sows so that one sow in each pair was fed ad libitum and the other a restricted amount for the whole of a 7 week lactation. Sows fed the ad libitum diet during lactation lost more weight either on a ''full" or "fasted" weight basis. Body water loss was significantly less than weight loss, measured in fasted-animals. Losses of water appeared to be considerable in 6 out of 8 animals. On average the composition of the liveweight loss contained more protein than fat. Liveweight loss was significantly correlated to its protein content. Values for non-esterified fatty acids in blood plasma of sows, measured before or after feeding were higher one day after weaning than a week later. 3. The growing pig: This study was undertaken to assess the role of the pig's large intestine in the digestion of fibrous diets. Four growing pigs fitted with a simple glass cannula at the terminal ileum were used to compare the digestion of three diets, each containing a fibrous, protein rich by-product, with a conventional diet containing soya bean meal according to a Latin square design. For the four diets containing soya bean meal, malt culms, dark grains and weatings, overall apparent digestibility coefficients of the dietary organic matter were 0.82, 0.78, 0.73 and 0.68 respectively. Corresponding values to the ileum were 0.07 lower in all cases. Overall nitrogen digestibility coefficients were 0.76, 0.69, 0.67 and 0.63 respectively. Corresponding values to the ileum were 0.03 lower on average. In the second trial, for the control, straw, sawdust and oat husk diets, overall apparent digestibility coefficients of the dietary organic matter were 0.82, 0,67, 0.62 and 0.62 respectively. Corresponding values to the ileum were 0.04, 0.08, 0.09 and 0.24 lower. Nitrogen digestibility coefficients to the ileum were 0.71, 0.35, 0.54 and 0.50 respectively. Measurement of amino acid digestibility carried out in the first trial showed that apparent digestibility of lysine was the lowest among the various essential amino acids when measured overall. Apparent digestibility of lysine and threonine to the ileum were also the two lowest values. The results regarding the rate of passage of the diets from the mouth to the terminal ileum were variable. |
