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Neither Photoperiod in the Farrowing Room Nor Time of Weaning Affect Nursery Performance

27 March 2015

Neither photoperiod in the farrowing room, nor the time of weaning affected the growth rate of piglets in the nursery, according to J. Shea, L. Eastwood and A.D. Beaulieu in the Prairie Swine Centre Annual Report 2013-14.


Weaning, which requires adapting to a new feed source and environment, may result in anorexia and reduced growth in the initial 24 to 48 hours in the nursery.

Prairie Swine Centre Canada
Laura Eastwood

This study was designed to determine if altering the photoperiod in the farrowing room and/or if weaning at the end of the light or the dark cycle would affect performance in the nursery. Pigs were given either a 16 hours light:8 hours dark (16L:8D) or a 8L:16D photoperiod while in the farrowing room, and weaned either at the end of the dark or the light cycle.

Neither photoperiod in the farrowing room, nor time of weaning affected growth rate in the nursery and nursery exit weights were similar among treatments.

Prairie Swine Centre Canada
Dr Denise Beaulieu

Pigs weaned at the end of the light period had more feeder visits in the first 24 hours post-weaning. However, this did not result in higher feed intake post-weaning. Neither photoperiod nor time of weaning had an effect on the percentage of pigs (34) identified as “eaters” during the initial 24 hours in the nursery.

Overall, photoperiod manipulation in the farrowing room did not benefit post-weaning growth rates. Interestingly, pigs exhibiting evidence of phase 1 consumption immediately post-weaning were the lighter pigs and they had higher ADG immediately post-weaning than those identified as non-eaters.


Successful pork production is highly dependent on sow productivity. The number of pigs born alive per sow per year is the parameter commonly cited, however, improvements are not realised if pre-weaning mortality increases or growth rate is not maintained post-weaning. A piglet experiences social, nutritional and immunological stressors at weaning. They are separated from the sow, moved to a new environment, mixed with non-littermates and expected to begin consumption of a novel diet.

Hours of light, or photoperiod, can affect performance through behavioural or endocrine (melatonin) mechanisms.

The following study focused on the behavioural aspects of the photoperiod.

In a previous experiment at the Prairie Swine Centre, a marked diurnal pattern was observed in nursery feeding behaviour post-weaning. Despite continuous lighting, feeder approaches declined markedly eight hours post weaning, remained low for eight hours, then increased again to the previous level. Thus, there was an eight-hour period when the feeder was under-utilised.

The authors hypothesised that the time of weaning and the photoperiod would alter this behaviour, and all pigs would take advantage of the availability of feed duirng the first 24 hours post-weaning.

The objective of this experiment was to determine if weaning at the end of a dark or light cycle would affect subsequent performance in the nursery and if this effect depended on photoperiod in the farrowing room.

Materials and Methods

Treatments consisted of two photoperiods in the farrowing room (16L:8D or 8L:16D) and time of weaning (end of the light or dark cycle) arranged as a 2×2 factorial. Each farrowing room was one photoperiod/time of weaning treatment. The experiment used 12 farrowing rooms, for a total of 157 sows and their litters (around 1,755 piglets).

Lighting, including that coming from heat lamps was standardised across farrowing rooms. Windows were covered to block external light. Light emissions were quantified at sow level, and averaged approximately 12 lux with the lights off and 43 lux with lights on. Sows were weighed on day 1 following farrowing and at weaning. Pigs were weighed at three days of age, one week prior to weaning and at weaning (day 26 ± 2). All pigs were weaned into nurseries maintained on a 16L:8D lighting regime at the beginning of a dark cycle.

At weaning, pigs were divided among treatments and sorted so that all pens within a treatment had equal body weight in the nursery. For the first 24 hours, the phase 1 diet was spiked with pellets containing ferric oxide (red dye which can be visualised in the faeces). Anal swabs were taken 48 hours into the nursery period to see which pigs ate in the first 24 hours.

Pigs and feeders were weighed on day 0, 7, 14 and nursery exit (eight weeks of age). Four pens were selected and still photos were taken every five minutes for the first 24 hours to monitor behaviour and feeder visits (Figure 1).

Prairie Swine Centre Canada
Figure 1. Still photos used to monitor piglet behaviour during a light or dark period.

Results and Discussion

Growth rate in the nursery, and nursery exit weights were unaffected by treatment (Table 1).

Table 1. Effects of photoperiod in the farrowing room, and the timing of weaning relative to photoperiod on the post-weaning growth performance of piglets weaned at 26 days of age
 Farrowing photoperiod (p)Time of weaning  
 8L/16D16L/8DEnd of
dark phase
End of
light phase
No. of piglets 887 868 837 918    
Age at weaning, days 24.9 25.6 25.6 24.9    
Age at nursery exit, days 54.2 54.9 54.4 54.7    
Piglet bodyweight, kg
Weaning 7.42 7.65 7.36 7.71 0.056 NS
Nursery, day 7 8.58 8.67 8.46 8.78 0.063 PxT
Nursery, day 14 10.96 10.85 10.78 11.04 0.136 NS
Nursery exit, day 56 22.04 19.79 19.31 22.53 1.734 NS
Average daily gain in the nursery, kg
Weaning to day 7 0.17 0.15 0.16 0.16 0.004 NS
Days 7 to 14 0.34 0.31 0.33 0.32 0.016 NS
Days 14 to 56 (exit) 0.74 0.59 0.57 0.77 0.116 NS
Weaning to exit 0.50 0.41 0.41 0.50 0.060 NS
Average daily feed intake in the nursery, kg
Weaning to day 7 0.16 0.14 0.15 0.14 0.001 P, T, P×T1
Days 7 to 14 0.35 0.37 0.34 0.37 0.002 NS
Days 14 to 56 (exit) 0.71 0.77 0.72 0.76 0.010 NS
Weaning to exit 0.51 0.54 0.52 0.53 0.015 NS
1 P×T, P=0.06.

During the first week in the nursery, the authors observed a photoperiod by time of weaning interaction for feed intake (Figure 2).

Prairie Swine Centre Canada
Figure 2. The interaction of photoperiod in the farrowing room and time of weaning (end of dark or light cycle) on ADFI from weaning to day 7 (SEM=0.001; P=0.06)

The lowest feed intakes were seen with pigs who were on the 16L:8D photoperiod and weaned at the end of the dark cycle. This effect, however, was not extended beyond the first week in the nursery.

Pigs weaned at the end of the light cycle averaged more feeder approaches in the first 24 hours post-weaning than those weaned at the end of a dark cycle, regardless of photoperiod. This however, did not affect feed intake. There was no evidence that treatment affected aggression.

The lighter piglets at weaning were more inclined to eat during the initial 24 to 36 hours in the nursery, had increased growth rates during week one in the nursery and nursery exit weights were similar (Table 2).

Table 2. Performance of piglets categorised as eaters or non-eaters1
Bodyweight, kg
Birth 1.53 1.53 0.015 0.92
Weaning 7.28 7.62 0.070 <0.01
Day 7, post-weaning 8.58 8.62 0.070 0.69
Nursery exit, post-weaning 19.64 21.02 1.950 0.56
Average daily gain, kg
Weaning to day 7 0.187 0.141 0.004 <0.01
Weaning to nursery exit 0.419 0.456 0.067 0.67
Average daily feed intake, kg
Weaning to day 7 0.154 0.149 0.001 <0.01
Weaning to nursery exit 0.502 0.519 0.002 <0.01
1 Phase 1 diet contained ferric oxide pellets for 24 hours post-weaning. Piglets categorised as an "eater" or "non-eater" based on anal swabs taken at 48 hours post-weaning.


Photoperiod manipulation in the farrowing room did not benefit postweaning growth rates. Piglets weaned at the end of the light period had more feeder visits in the first 24 hours post-weaning. This however, did not translate into greater feed intake post-weaning.

Acknowledgements: The authors are grateful for support for this project from the Saskatchewan Agriculture Development Fund. Program funding for Prairie Swine Centre, Inc. from Sask Pork, the Manitoba Pork Council, Alberta Pork, and Ontario Pork is gratefully acknowledged.

March 2015

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