Research On The Optimization Scheme Of The Lighting System For Nursery Pigs

Illumination is one of the most important environmental factors on swine farms and affects growth and reproduction by regulating the physiological rhythms of pigs.When weaned piglets are transferred to nursery,the double stress of herd transfer and lighting regime will affect the growth performance and increase the dead rate of piglets of pigs.However,there are few research on the lighting system for pigs during nursery stage in China,and large-scale breeding enterprises mostly rely on production experience to develop lighting system for nursery pigs.This project aims to establish a reasonable lighting scheme for nursery pigs,this study aimed to provide a theoretical basis and practical guidance for the selection of the lighting scheme for nursery pigs by comprehensively evaluating the growth performance of nursery pigs in different lighting duration,lighting intensity and their interactions,in addition,we verified this lighting system.The main results are as follows:In experiment 1,630 nursery pigs of 28 days of age,healthy and of similar weight,were selected and treated with different lighting regimes(12 h,16 h,20 h of lighting duration and 40 lx,75 lx,120 lx of lighting intensity in combination with each other).The daily feed intake of piglets and the weight of piglets at 30,40,50 and 60 days of age were recorded and counted.The results are shown below:(1).Lighting duration affected the growth performance of nursery pigs.The optimum lighting duration for piglets in the early stage was 16 h,and with the increase of age,the lighting duration required to improve the growth performance of nursery pigs tended to decrease.During the nursery period(30～60 days of age),lighting duration of 16 h was highly significantly higher than the average daily gain(ADG)of piglets with 12 h and 20 h lighting duration(P < 0.01).The ADG of piglets at 30～40 days of age with 16 h of lighting duration was significantly higher than that of 12 h(P < 0.05),and the difference in ADG between 16 h of light and 20 h of light was not significant(P>0.05),but the feed-to-weight ratio(F/G)of 16 h of lighting duration was extremely significantly lower than that of 20 h(P < 0.01).(2).Lighting intensity affected the growth performance of nursery pigs,and the optimum lighting intensity for piglets was 75 lx.During the nursery period(30～60 days old),the ADG of nursery pigs with a light intensity of 75 lx was significantly higher than that of40 lx(P < 0.05).The lighting intensity of nursery pigs at 30～40 and 40～50 days of age did not affect the ADG of piglets,but the feed-to-weight ratio of nursery pigs at 30～40 days of age with light intensity of 75 lx was extremely significantly lower than that of 40 lx and120 lx(P < 0.01).(3).Lighting duration and lighting intensity interacted to influence the growth performance of nursery pigs.We defined the lighting duration multiplied by the lighting intensity(reciprocal work)as the exposure(lx·h).The results showed that the exposure had a significant effect on the ADG and feed-to-weight ratio of nursery pigs,and the optimal exposure of piglets at different growth stages was different.They were 1200～1500 lx·h in the 30-40-day-old stage,900～1440 lx·h in the 40-50-day-old stage,and 640～900 lx·h in the 50-60-day-old stage.The ADG of nursery pigs was the highest and the feed weight ratio was low within the optimal exposure range.In experiment 2,in order to verified and improved the optimal light system in experiment 1,280 nursery pigs of 28 days old with similar health condition and weight were selected,and the light systems chosen for the experiment were 12 h/75 lx,20 h/75 lx,B16 h/75 lx,B16 h/100 lx(B16 h meant that the lighting time of nursery piglets was 16 hours from the age of 30 days,and the lighting duration was shortened by 2 hours every 10 days,that was,the lighting duration of 30～40 days was 16 hours,and the lighting duration of 40～50 days was 14 hours,and the lighting duration of 50～60 days was 12 hours).Recorded and counted the daily feed intake and the weight of piglets at 30,40,50 and 60 days of age.The blood immune indexes and serum melatonin levels of piglets at 60 days of age were detected by Enzyme-linked immunosorbent assay.Calculated the power consumption under different lighting schemes in the nursery farm according to the results.The purpose of this study was to explore the optimal lighting regime for the nursery stage of piglets.The results are shown below.(1).The effect of the lighting regime set in experiment 2 on the growth performance of nursery pigs was verified and improved.In experiment 1,extending the lighting duration in the early growth period of nursery pigs could improve the ADG of piglets.The lighting duration showed a decreasing trend,and the recommended lighting intensity for nursery pigs in the experimental farm was 75 lx.(2).Different lighting duration and lighting intensity treatments affected the serum immunoglobulin M(Ig M)but not serum immunoglobulin G(Ig G)levels in nursery pigs.The serum Ig M content of nursery pigs in the 20 h light duration group was significantly higher than that in the 12 h and B16 h groups(P < 0.01);the serum Ig M content at a light intensity of 100 lx was significantly higher than that at 75 lx(P < 0.05).(3).Lighting duration affected serum melatonin(MT)levels in nursery pigs,while lighting intensity had no effect on serum MT levels.The serum MT content was highly significant higher in the 12 h light time group than in the B16 h and 20 h light time groups(P < 0.01),and the difference in serum MT content between the B16 h and 20 h light time groups was not significant(P > 0.05);the difference in serum MT content between the 75 lx and 100 lx light intensities was not significant(P > 0.05).