With the data obtained so far, we visit the farm and the owner confirms that they are inducing farrowing on day 113 for sows to farrow on day 114. The procedure they use is the following: injection of prostaglandin on day 113 and administration of oxytocin to those sows that have begun to show signs of onset of farrowing. Upon entering the pens, we begin to see small and weak piglets (Figure 6) that we quickly link to the premature farrowing synchronization.
Figure 6: Photograph showing some weak or low birth weight piglets.
We verify that the feeding curve in gestation and prefarrowing is the recommended for this type of sows. In addition, all the parameters we measured support a case of low weight and lack of vitality in newborn piglets due to prematurely induced farrowing. Therefore, we decide to stop the induction in order to confirm the actual gestation length in this farm and, once defined, resynchronize it if so desired by the owners and operators —this time, however, on the appropriate date.
Simultaneously, since the only farrowing operator is accustomed to the use of oxytocin to make all sows farrow on schedule, we deliver training on more natural delivery methods. We also teach them how to collect data correctly and introduce them into the management software in order to analyze them later.
The change in procedures was conducted on the first week of June this year, 2014.
Despite the farrowing operator’s concerns, since she is not happy about some of the sows farrowing alone at night, the next batches are not synchronized and, as expected, gestation lengthens, in our case up to 2 days. From that moment we start to produce the first reports.
As indicated in the previous paragraph, gestation lengthens to 116 days (Figure 7) compared to the previous 114.6, and heavier livelier piglets begin to be born.
Figure 7: Gestation length of induced farrowing at 114 days versus natural farrowing.
The number of stillborns in induced farrowings was 8.4%, not too high but susceptible to improve. Data obtained from the moment this practice is stopped and more natural management methods are adopted —with less use of oxytocin— indicate that the stillborn percentage is reduced by 40%, —i.e., to about half the previous percentage—, to an average of 5.2% stillborn (SB), as shown in Figure 8.
Figure 8: Changes in the percentage of stillborn piglets before and after allowing the sows to farrow naturally.
Thanks to the combination of a decrease in the number of SB piglets and an almost 30% decrease of preweaning mortality (PWM) (down to 10.2%), the ultimate goal is finally achieved: to wean an additional piglet per sow. From that moment their average number of weaned piglets per sow is 10.9 versus the previous 9.6 (Figure 9).
Figure 9: Induced farrowing (at 114 days) outcomes versus natural farrowing.
To this day (October 2014), they have not induced farrowing again. The operator, who was not convinced at the beginning of the process, tells us the change has made her work easier. Farrowing is now taking place in stages over several days and the operator has more time to look after the piglets, feeding them the colostrum properly (Figure 10) and care for the weakest ones, such as those suffering from splay leg. She also tells us that, on the whole, the piglets are more autonomous when searching for the sow's nipples and taking the colostrum (Figure 11).
Figures10 and 11: The operator has more time to feed the colostrum and care for the weakest piglets.
This farm implements an intensive work schedule. Since the protocol change that took place in June —when they stopped using prostaglandin to synchronize the sows—, they all together decided that the operator had a split day on the 3 busiest farrowing days. Another operator has been trained to implement the farrowing procedures when the previous one is on her lunch break and her workmates finish their workday.
On the one hand, this study shows that an incorrect intervention with the animals can have a negative impact on production. Farrowing is a natural process for the sow; you need to control the process, but always having a sound knowledge of the genetic characteristics of the sows you are working with and adapting procedures (or removing them if necessary) to their specific needs.
On the other hand, analysis of the data collected on farms is a basic support tool, which supplements direct observation on farm, and helps troubleshooting and monitoring the results of the changes applied.