The importance of lighting in the gestation area (especially where newly weaned sows and sows being mated are located) has been widely demonstrated and is known to all. The sows are particularly affected at the end of the year, in autumn, when the intensity and hours of light decrease progressively, which is commonly known as "decreasing photoperiod".
Although it has been a known factor in the industry for many years, there are still some cases in which this very basic aspect of the sow's physiology is not taken care of.
One of the main tools to encourage the use of extra lighting equipment in the mating area is the data analysis, and more specifically the weaning-to-first service interval (W1stS), one of the easiest parameters to measure in pig production.
The case presented below is a 1100-sow site. To get to know the dynamics of the farm, a historical reproductive analysis of the last 4 years is carried out, both in farrowing and in gestation. One of the features the data analysis highlighted immediately was the strong seasonal effect on the sows in relation to the weaning-to-first service interval. A problem that was also getting worse year by year, reaching a value of 13 days in September 2016 (figure 1).
There was an immediate suspicion of poor lighting in this area of the farm. At the time of the visit, it is confirmed on site that the entire stall gestation barn (including gilt adaptation and mating) had very poor lighting, aggravated by the use of dark blue fibreglass windows, which should remain almost totally closed at this time of the year due to the drop in temperatures.
During the visit, it was recommended to install an extra lighting system that could reach 300 lux, with a timer to guarantee 16 hours of light per day.
The extra lighting was implemented during the second week of October 2017. As Photo 1 shows, the gestation barn is divided into two areas (one for multiparous and one for nulliparous) by a wall and a door. At this time the extra lighting equipment had only been installed in one of the areas, and the enormous difference in lighting before and after is clearly visible.
The results came about very quickly in relation to the weaning-to-first service interval, that was immediately reduced from 9.9 days in the last quarter of 2016 to 6.2 days in the same period in 2017, a decrease of 3.7 non-productive days (table 1). In addition, as Figure 1 and Table 1 show, the pattern of increase of the W1stS was getting worse every year, affecting the sows most severely.
Table 1.Weaning-to-first service interval (W1stS) from 2014 to 2017 by month
Each non-productive day costs around 2 - 2.2 euros. This farm has about 50 weanings every week. Only in 3 months, the farm saved around 3700 euros thanks to the reduction of non-productive days in weaned sows that are being mated.