Sarah Derking (2015)
Field study on high-yielding sows on the influence of feed on the development of body mass and back fat thickness during lactation as well as on the performance of the piglets (litter gain)
The aim of this field study was to gain basic data in feeding high performing sows during lactation, including body mass and its development, performance (number of piglets, litter weight at birth and weaning) as well as development of body composition of the sows (back fat thickness as an indicator). Besides, the course of parturition and puerperium and also the potential effects on the fertility concerning the next reproductive cycle was of interest.
The investigation took place in a piglet producing farm with sows of mainly Danish genetics from June to December 2013. 130 sows were allotted to four trials (T) and were fed standard mixed feed for lactating sows (energy content 13.4 MJ ME / kg dm) either twice or three times a day restrictively (T I and II), or almost ad libitum (T III and IV). A high energy feed supplement (mixture of extruded corn / flaxseed) was supplemented in T IV, which was divided into three groups (A, B, C) with the following procedure; five days a.p. to five days p.p. (B), resp. during the entire investigational period (C).
By quantifying the feed consumption, the energy and nutrient intake was determined.
The development of the body condition and the performance of the sows in this period including a few days before parturition until weaning was investigated by the following parameters: body mass (BM), back fat thickness (BFT), body condition score (BCS) and litter mass resp. litter gain. An evaluation of the feces (dry matter content) was done in trial IV. Furthermore, clinical diseases, the interval from weaning to estrus and the key data on the litters were recorded.
For the measurement of the BM, specificially constructed scales were used, which consisted of two weighing boards and a display unit. The BFT was determined according to the guidelines for the individual performance testing of breeding sows.
For this purpose, the lean meater (by Renco, Minneapolis, USA) was used.
The main results of this field study can be summarized as follows:
1. The average BM directly after parturition of the gilts amounted to 194 kg. Until the fifth parity, BM increased to an average of 252 kg, which stayed constant later on.
2. Between the three days a.p. and directly after parturition, the sows lost average between 18.8 kg (T IV A) to 29.2 kg (T I) on average.
3. The total number of piglets born per litter was between 15.0 (T IV A) and 18.5 (T IV C) piglets on average, the number of piglets born alive varied between 13.6 (T IV A) and 16.4 and the number of stillborn piglets between 1.36 (T IV A) and 2.10 (T IV C) on average.
4. The litter mass at birth varied considerably between 17.4 kg (T IV A) and 23.3 kg (T II) on average. At weaning, the litter mass came to 77.3 kg (T IV A) and 86.9 kg (TI) on average.
5. The sows’ BM-losses (directly p.p. until weaning after a lactation period of 24.4 to 26.1 days varied between 1.44 kg (T III) and 16.6 kg (T I). This parameter was influenced by the feeding concept. The sows fed restrictively lost on average 16.6 kg (T I) resp. 14.5 (T II) BM during lactation, whereas the sows fed almost ad libitum gained weight in the second resp. third week of lactation.
6. The losses of BFT amount to 2.10 mm (T IV C) to 3.50 mm (T IV A) on average. Although there was an increase in BM within some groups, there was rarely a gain in BFT.
7. The energy intake of the sows reached only 77.0 MJ ME per day on average in lactation (T IV C; d1 – 25), even when fed almost ad libitum twice a day.
8. Calculating the milk yield from the litter weight gain considering the piglets’
feed intake, it amounted to 10.5 l to 11.4 l per sow and day on average.
10 % of the sows reached a performance of 13.4 l, the maximum was about 15 l per day.
9. Usually less than 15 % of the sows were suffering from the MMA-syndrome.
The body internal temperature on the first day p.p. was about 38.8°C on average. Some sows reached temperatures of more than 39.5 °C without further clinical symptoms (normal feed intake, no unphysiological vaginal discharge, no mastitis).
10. The sows fed almost ad libitum tended to have a shorter interval from weaning to estrus (between 4.64 (IV A) and 4.93 (III) days on average, with the exception of IV B; 8.55 days) than the sows fed restrictively (7.19 / 7.13; I / II).
Meeting the energy requirements of sows in lactation and suffering only from marginal BM and BFT losses despite a high performance is an aim which can only partly be achieved. A higher frequency of meals and an ad libitum feeding increased the feed intake. The loss of body mass, as well as the loss of back fat, is in particular reduced by an ad libitum feeding regimen. The addition of a high energy feed can result in an additional energy and nutrient intake and positively influences the development of BM and BFT in sows. With a comparable litter gain, sows therefore keep a better body condition, which may affect i.a. their fertility. Still the sows in every trial lost body mass and back fat in the fourth week of lactation, this loss of back fat was very low particularly in the sows fed ad libitum. Thus, there is no evidence to suggest that this additional loss can be detrimental to the sows fed appropriately, whereas a suckling period of four weeks is an advantage to the piglets for economic as well as for animal welfare reasons.