Gesundheit und Leistung von Sauen nach unterschiedlicher Fütterung in der Trächtigkeit (übliches Alleinfutter restriktiv im Vergleich zu trockenschnitzelreichem Mischfutter ad libitum)

Aim of the field study in two pig farms was to test the potential influences of two different feeding concepts in pregnant sows. The feeding trials were carried out with pregnant sows (35th up to 108th day of pregnancy; n = 569) which were fed restrictively with an usual complete diet (~12-13 MJ ME, 5 % crude fiber) or ad libitum with a mixed diet rich in sugar beet pulp (~ 9 MJ ME, 13 % crude fiber). Restrictively fed sows were hold in crates (control; n = 261), whereas the ad libitum provided sows (trial group; n = 308) were kept in groups. Under these conditions on one hand the ingested feed amounts as well as energy and nutrient supply were of interest. On the other hand potential effects on health and reproductive performance of the sows should be proofed. The sows were observed over the reproductive cycles (pregnancy, parturition, puerperal period, lactation) and different parameters (developement of body weight and back fat thickness [BFT], clinical symptoms, reproductive performance) were investigated. Data were sampled within a period from May 2003 up to April 2004. Investigations of feedstuffs were done by conventional analytical methods (weender analysis, usual mineral determination). In samples of faeces the dry matter content was analysed (24 h drying, 107 °C) as well as the consistency (penetration depth of a cone into the sample). Furthermore, the pH-data in urine were determined on day 35 and 108 of pregnancy. Measurement of the BFT was done via the recommended method for the examination of the individual performance in breeding animals (ultra sound: Lean Meater, Fa. Renco, range 3). The following results could be observed: 1. Daily feed intake during pregnancy (35th to 108th day p.c.) amounted on average 4 kg in sows fed ad libitum, whereas the restrictively supplied sows had an average intake of 2.9 (farm I) and 2.4 kg (farm II). 2. The high amounts of feed intake in sows fed ad libitum caused an energy (and nutrient) oversupply in sows (38 MJ ME/day compared to a requirement of 33 MJ ME/sow/day), especially during first phase of pregnancy (35th to 80th day). 3. The higher feed intake of sows fed ad libitum compared to the restrictively fed ones led (under the premisse of identical costs of both diets of 14 Euro/100 kg feed) to additional costs of 36 Euro per sow and year. Otherwise, the ad libitum concept is combined with lower investment costs for feeding technique. 4. On both farms the body weight gains (farm I: 53 ± 18 kg; farm II 54 ± 21 kg) during pregnancy (35th to 108th p.c.) as well as body weight losses during lactation (farm I: 43 ± 14 kg; farm II: 32 ± 15 kg) in sows fed ad libitum were higher compared to sows fed restrictively (body weight gains: farm I: 42 ± 15 kg; farm II. 42 ± 19 kg; body weight losses: farm I: 33 ± 16 kg; farm II: 21 ± 20 kg). These higher increases and decreases of body weight in ad libitum fed sows can be explained mainly by a higher gutfil (on average 12 kg). 5. On the 108th day (change into the farrowing crates) the variation of individual body mass (given as variation coefficient) was slightly lower (farm I: 10.8 %, farm: 12.9 %) than at the beginning of the feeding experiment (day 35th p.c.). 6. In sows fed ad libitum there was an increase of their back fat thickness (day 35th p.c.: farm I 17.8 ± 2.6 mm, farm II: 17.3 ± 3.2 mm; 21st day p.p.; farm I: 19.3 ± 4.6 mm, farm II: 19.2 ± 4.4 mm) during the reproductive cycle (35th day p.c. to 21st day p.p.) whereas in sows fed restrictively during pregnancy the BFT rather was reduced. The proportion of sows with a too low or critical BFT (< 16 mm) at the end of pregnancy (108th day) was much higher in restrictively fed sows (farm I: 12.8 %; farm II: 24.4%) compared to sows fed ad libitum (farm I: 3.4 %, farm II: 9.0%). 7. The mixed diet rich in sugar beet pulp influenced positively the quality of faeces (higher moisture level, softer consistency); otherwise, the diet rich in sugar beet pulp led to higher pH data in the urine (pH 7.5; control: pH 7.1). 8. The farm specific influences on the performance of sows regarding the piglets (proportion of alive and dead born piglets, birth weight of piglets, litter weight, losses) were higher than the influences of the two different feeding concepts. There was no higher incidence of piglets losses squeezed by the sow in litters of sows fed ad libitum during pregnancy. 9. In general, directed influences of the feeding concepts on health or the incidence of clinical disorders in sows during pregnancy, the course of parturition (necessary obstetrics, proportion of death born piglets) and lactation until weaning (course of puerperal period and lactation) could not be observed. At most farm specific effects caused differences in health and performance. On farm II sows of control group had a higher incidence of metritis, mastitis and agalactia (23 %; trial group: 8 %), necessary obstetrics (26 %; trial group: 11 %) as well as dead born piglets (8 %; trial group: 5 %). 10. On farm I the higher average back fat thickness (ad lib. > restr.) influenced the interval from weaning to oestrus at least in tendency (interval of 4 days: 19.9 ± 3.81 mm [ad lib.] and 17.8 ± 2.56 mm [restr.]; interval of 6 days: 16.8 ± 3.25 mm [ad lib.] and 16.0 ± 3.83 mm [restr.]). Conclusions Feeding of mixed diets rich in sugar beet pulp can be recommended for pregnant sows under practitional conditions. The housing of pregant sows in groups as well as offering a diet rich in fiber fullfill the demands of animal welfare. Health and performance were not influenced negatively by the ad libitum feeding during pregnancy. Otherwise, this feeding concept is combined with an energy and nutrient oversupply. The low cost of investment of this feeding concept and the simple apply and conversion of this system (and these points compensate the higher feed costs) give cause for a recommendation of the ad libitum feeding as a concept for pregnant sows to the practice.