Introduction

There is an on-going discussion regarding how the care and treatment of female mammals during pregnancy may impact the subsequent performance of their offspring. In those cases where differences in care among pregnant females do alter subsequent progeny performance, this is called foetal programming. In essence, the care during gestation 'programmes' the developing foetus in such a way that after birth, it grows and develops differently than what may be expected. This interest in possible alterations in animal performance due to gestation management is being studied in pigs as well. It is generally regarded that if pregnant gilts or sows are provided adequate feed, water, space and an appropriate thermal environment (cooling in the summer, warmth in the winter) that gestation environment does not influence subsequent offspring performance.

However, this may not always be the case. As Michigan producers start to consider how compliance with recent legislation (P.A. 117) may alter how they manage gestating sows, it is relevant to consider how group housing gestating sows may influence the performance of their subsequent offspring.

A recent paper studied the subsequence performance of offspring from gilts housed in different types of housing during gestationa. This study reported that Yorkshire-Landrace F1 gilts were mated and housed in either 1) gestation stalls, 2) gestation pens or 3) stalls for the first 30 days of gestation and then gestation pens. Gestation stalls were 2‘ × 7‘, while gilts housed in pens were allocated 25.5 to 30.5 square feet per animal. Gilts were fed 6lb per day of gestation feed that met or exceeded NRC (1998) requirements. At 110 days of gestation, gilts were placed into standard farrowing stalls and remained there through lactation. Pigs were weaned at approximately 24 days of age. At weaning, gilts were placed into nursery pens by weight and these groups of gilts remained intact through the end of the finishing phase. Gilts were placed on self-feeders and fed rations that met or exceeded NRC requirements for each of the nursery and grow-finish phases. At approximately 240lb, gilts were removed from finishing and were limit-fed 5lb of feed per day and exposed daily to mature boars to detect oestrus.

Results

The results from this study can be viewed as two different parts. The first part is how gilts housed differently during gestation performed during lactation, while the second part regards differences in performance of offspring from gilts housed differently during gestation.

The farrowing performance of gilts which had gestated in one of these three housing systems could be considered a possible preview to how first litter performance for gilts gestated in groups may differ from a farm's previous experience of gestating gilts in stalls. Gilts that gestated exclusively in stalls were similar in weight at mating and at farrowing (Table 1) compared to gilts in the other two gestation housing treatments. However, during lactation gilts that gestated in stalls exclusively, lost less weight and backfat thickness during their first lactation than females that had gestated in either group housing treatment. Gilts that had gestated in stalls exclusively or in stalls for 30 days and grouped into pens had similar number born alive, compared to each other but was greater than gilts that had gestated in groups throughout gestation (Table 1.). However after cross-fostering across treatment groups, all females regardless of gestation housing treatment had similar number of pigs weaned per litter and similar pig weaning weights.

Gilt offspring, regardless of dam gestation treatment had similar grow-finish average daily gain (Table 2; average = 2.17lb per day). However, gilt offspring whose dams gestated in stalls exclusively or had gestated in stalls for 30 days and then grouped into pens had better feed efficiency than gilt offspring whose dams gestated in pens exclusively (Table 2). Gilt offspring whose dams had gestated in stalls exclusively were leaner at 240lb than gilt offspring whose dams had gestated in either group housing treatment. Furthermore, fewer gilt offspring whose dams had been housed exclusively in stalls throughout gestation expressed their pubertal oestrus by 165 days of age compared to gilt offspring whose dams gestated in either group housing treatment (Table 2). However, though not shown, by 210 days of age, there was no difference in the occurrence of puberty of gilt offspring regardless of dam gestation housing type.

This study does demonstrate that the type of gestation housing a female is penned in during gestation may cause foetal programming. That is, subsequent offspring from dams gestated in different types of gestation housing can perform differently. This provides some insight to how pig performance may change after switching gestation penning. Dependent on the type of group housing system chosen for gestating gilts, producers who switch from stalls to group housing may see subsequent offspring be slightly fatter and feed efficiency could worsen. However, if farms maintain an internal gilt multiplication programme, gilts from dams gestated in group housing may achieve puberty at a younger age and therefore have experienced more estrous cycles before mated for their first litter, if mated at a constant age.

Conclusion

Gilts housed in different gestation housing types did have gilt offspring perform differently. This suggests that gestation housing system could cause foetal programming. Producers should take note that growing pig performance could differ from previous experience due to a change in gestation housing systems. However, further research is needed to determine how prevalent this effect may be on barrow progeny grow-finish performance as well as determine if replacement gilt farrowing and lactation performance is impacted by the type of gestation housing in which their dams were penned.

Reference

Estienne, M.J. and A.F. Harper. 2010. Type of accommodation during gestation affects growth performance and reproductive characteristics of gilt offspring. J. Anim. Sci. 88:400-407.

July 2010