| According to two environmental patterns in late spring early summer and summer period,daily increasing temperature and sudden heating.In order to arrive at the inflection point temperature of broiler non-contactk indexes.Establish the temperature and humidity index model of broiler.Aim at providing a scientific basis for broiler warm environment and fine management.Study 1 Study on the model of broiler non-contact physiological indexs in daily increasing temperatures at different humidity.In this study,the effects of different relative humidity?RH?on the physiological model of broilers in increasing temperatures were studied.A total of 180 22-day-old Arbor Acres?AA?male broilers were allotted into environment controlled chambers and randomly divided into three treatments with 6 replicates per treatment and 10 chickens per replicate.Adaptation period for 7 days,temperature 20 ?,RH 60%.When broilers were 29-day-old,RH was adjusted to 35%,60% and 85% of three treatments,respectively,to the end of the test.The temperature of the environment controlled chambers were increased by 2? every day,the test period was 9 days.During the experiment,no touch,non-contact physiological indicators were measured,there was no stress to chickens.We determined the T above which certain animal variables started to change: the so-called inflection point temperature?IPt?or “upper critical temperature”.The results showed that there were IPts in core temperature?CT?,earlobe temperature?ET?,leg temperature?LT?,respiratory rate?RR?,feed intake?FI?,drinking water?DW?,mortality rate?MR?,gape rate?GR?the first indicator of reaction,LT,was in the range from 24.6 to 25.1 ?,at the same time broilers have mouth opening phenomenon,was in the range from 24.7 to 25?.Followed by ET and CT,was in the range from 25? to 25.1?,25.5 to 26.4? each.RR has two IPts?IPt1,IPt2?,in the range from 25.5 to 27.2? and 32.5 to 33.3?,RR increases with the increasing temperature above IPt1,RR decreases with increasing temperature above IPt2.FI and DW were changed in the range from 27.1 to 29.3?,29.2 to 29.5? respectively,FI and DW were decreased with increasing temperature above IPts.The IPts of CT,ET,LT,RR,FI and DW under high humidity were the lowest than other treatment.ambient temperature strongly affects the physiological indexes of broilers,whereas RH has a relatively minor effect on it.The upper critical temperatures can be considered to be the IPt above which FI decreased and RT then increased.The upper critical temperatures for 45 weeks old broiler CT are between 25.5 and 26.4?;between 25.5 and 27.2? for RR decreased;between 27.1 and 29.2? for FI increased;between 32.7 and 33.5? for death.When the broiler died,the difference between the highest value of CT and the constant values are in the range from 4.6 to 5.1?.45 weeks old broiler chickens have different upper critical temperatures for different physiological indexes.The THI model of CT is established:THICT1=0.74×Tdb+0.26×Twb?The curve of CT change with THI: CT=0.0107×THICT22-0.3856×THICT2+44.621?R2=0.7091?Study 2:Study on the model of broiler non-contact physiological indexs in sudden heating at different humidityA total of 360 22-day-old Arbor Acres?AA?broilers were allotted into environment controlled chambers and randomly divided into eighteen groups?six temperatures×three humidity?,20 chickens per group,half of the rooster and half of the hen.Adaptation period for 7 days,temperature 20?,RH 60%.Six temperatures were respectively 20?,23?,26?,29?,32? and 35?,three humidity were respectively 35%,60%,85%.The temperature of the environment controlled chambers were transferred to fixed value at ten o'clock in the morning,lasted for 3 hours.The results showed that after acute heat stress there were IPts in RR,LT,ET,CT,the first indicator of reaction,RR and LT,was in the range from 21.4 to 22.6? and 21.4 to 22?.Followed by CT,was in the range from 22.1? to 26.7?.And soon,ET also began to increased,was in the range from 23.4 to 26.2?.When the environment temperature exceeds the target IPt,as the temperature increases,RR,LT,CT and ET rise,When the environment temperature in the range from 29.7 to 31.7?,with the environment temperature rise,RR began to decline.The IPt of CT in low humidity group was significantly higher than in middle and high humidity group.The IPt and C of ET in low humidity group was significantly higher than in middle and high humidity group.The K and C of CT in middle humidity group was the mix.Humidity has no effect on RR parameters.The C and K in high humidity group was the max,but the difference is not significant.The THI model of CT is established:THICT2=0.84×Tdb+0.16×Twb?The curve of CT change with THI: CT=0.0107×THI CT22-0.3856×THICT2+44.621?R2 = 0.7091?... |
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