Do we fully understand gilts? Do we treat them as they deserve?

When servicing females on the farm, and considering only first services (without returns) gilts and weaned sows are two different types of animals. Virtually all weaned sows come into service from a catabolic state (weight and body condition loss during lactation), which negatively affects the processes of coming into heat and maintaining gestation. Since gilts are not in this catabolic condition at the time of service, it would be expected that they would have the best performance.

However, if we analyse data from the PigCHAMP Pro Europa database (300,000 sows), breaking down the results of the first services in 2018 by cycle, we find the following:

The first two cycles show the worst performance, both in % returns and in farrowing rates. In the second cycle this poor performance can be somehow expected since the sows are serviced following their first lactation. It is well known that loss of body condition is usually greater during the first lactation than in the following lactations. However, in the first cycle, when gilts theoretically are in optimal body condition with adequate fat reserves, the result is lower than one would expect.

Looking further into the servicing results, the different types of reproductive failures are shown below by cycle.

Table 1- Reproductive losses 1st service 2018 (689,024 services), PigCHAMP Pro Europa database (301,250 females)

Cycle	1	2	3	4	5	6	7+	Average
% Returns	7.7	9.3	6.7	6.1	5.7	5.4	4.6	6.7
Average return interval (days )	37.1	34.9	34.8	33.7	33.6	34.1	33.5	34.9
% negative to pregnancy Dx	1.4	1.5	0.9	0.9	0.9	1.0	1.2	1.2
% Not in Pig	1.2	1.0	0.8	0.7	0.7	0.7	0.7	0.9
% Abortions	1.6	1.3	1.3	1.3	1.3	1.3	1.3	1.4
% Dead	1.7	1.5	1.6	1.5	1.6	1.7	1.9	1.6
% Sold	2.2	2.1	1.8	1.9	2.2	2.5	4.0	2.3

The most noticeable differences between gilts and sows are:

• As mentioned, a higher % of returns and also a higher average return interval. That is to say, gilts have more returns between days 38 and 44 post-service and late returns.

• Related to the above, also a higher percentage of gilts with a negative pregnancy test: females that did not have a heat detected, or that have lost the gestation after insemination.

• Finally, gilts have more pregnancy losses in the second half of gestation: The % of abortions and not-in-pig is higher than in the rest.

In light of these results, the possible causes of this below-expected performance are:

• We don't fully understand gilts. These females have some different characteristics than do multiparous sows: shorter and irregular heat, harder to detect heats, and greater difficulties in intrauterine insemination. These differences may not be fully taken into account.
• Gilts do not receive the attention they deserve. Gilts are at an advantage not coming from a previous lactation, but have the disadvantage of needing to adapt to the existing pathology on the farm (even on farms producing their own replacements, some level of acclimation is necessary). When grouping gilts after pregnancy check, these females have greater difficulties. An established protocol along with sufficient facilities and working time are required for gilts to acclimatize as for the correct subsequent stimulation process and also the acclimation to group housing. This is not always fulfilled, because sometimes the farmer is not fully aware of the consequences that come from improperly handling these animals. For example, it is not uncommon to hear phrases such as " I'm just going to put the gilts earlier into gestation pens, it is not a big deal." In this regard, we must bear in mind that:
• Normally, gilts make up the largest group on the farm. Therefore, a lower-than-expected performance in this group of animals significantly affects the overall performance of the farm.
• The performance during the first cycle is closely related to the overall performance of the sow (see article "At long last, we can now predict a sow's performance from her first farrowing"). Therefore, if we achieve a high performance during that first cycle, it is very likely that the sow will maintain a higher performance for the rest of her productive life.

From the data, it seems clear that in general, one of the areas in which our industry has room for improvement (which could become very profitable) is everything related to managing the future breeding females of the farm.