two reduced nocturnal temperature regimens for early-weaned pigs

TWO REDUCED NOCTURNAL TEMPERATURE REGIMENS FOR EARLY-WEANED PIGS's2

M. C. Brumm3 and D. P. Shelton4

University of Nebraskas, Concord 68728

ABSTRACT

Two experiments, each consisting of three trials and using 3- to Cwk-old newly weaned pigs, were conducted to evaluate the effects of two reduced nocturnal temperature regimens on weaned pig and subsequent growing-finishing performance and nursery energy (propane and electricity) use. In Exp. 1, nursexy treatments were 1) a control temperature (0 regimen of 30'C constant air temperature lowered 2c'/wk and 2) a regimen for pigs in pens with hovers (MRNT-H) in which the temperature from 1900 to 0700 beginning 1 wk after weaning was lowered 6c' from the 0700 to 1900 temperature setting, which was 3c' lower than CT. The nursery temperature treatments in Exp. 2 were 1) CT and 2) a 1OC' reduction in air temperature (MRNTlO) from 1900 to 0700 from CT beginning 1 wk after weaning. In addition, within each temperature, diet sequences of 1.2% lysine for 3 wk followed by 1.0% lysine vs 1.15% lysine offered continuously were evaluated. In Exp. 1, there was no effect (P > .l) of temperature on feed intake but ADG decreased (P < .001) in two of the three trials for MRNT-H vs CT and feed/gain worsened (P < .05) in all trials. In Exp. 2, there was no difference between MRNTlO and CT for ADG and feed/gain. No interaction was observed between nursery diet and temperature regimen for weaned pig performance. There was no effect (P > .l) in either experiment of nursery temperature on subsequent growing-finishing performance. Overall energy savings comparing the MRNT- H and CI' treatments were 68 MJ per weaned pig. Energy savings for Exp. 2 were 79 UT per weaned pig. Application of cyclical temperatures in a controlled manner can result in energy savings of approximately $ S O per pig weaned under the conditions of these experiments. Key Words: Nocturnal Temperature, Pigs, Hovers, Early Weaning

J. Anim. Sci. 1991. 6931379-1388

lntroductlon

Current recommendations for housing 3-wk-old weaned pigs call for air temperatures of 29'C at pig level, with temperature reductions of approximately 2c'/wk to a minimum

'Journal series No. 9271, Agric. Res. Div., Univ. of

h e authors acknowledge the assistance of

bept. of ~nim. sci. %ept. of Agric. Eng. hortheast Res. and Ext. Center. Received July 9, 1990. Accepted October 19, 1990.

Nebraska.

Forsberg with animal care and Jim Dahlquist and Kevin Fairbanks with data collection and analyses.

of 21'C at 8 wk of age ( M W P S , 1983) or 18 kg live weight (Aheme et al., 1987). Although these recommendations are based on a 24-h constant temperature, pigs have demonstrated a preference for reduced temperatures during nighttime hours (Cur t is and Moms, 1982; Momson et al., 1987, 1989). Brumm et al. (1985), Brumm and Shelton (1988), and Neinaber and Hahn (1989) have demonstrated improved weaned pig performance when nursery room air temperatures were reduced at night, although Swinkels et al. (1988) in a single trial demonstrated no difference in performance.

Hovers have been demonstrated to be a management tool that can significantly reduce nursery energy usage while providing for the

1379

1380 BRUMM AND SHELTON

pigs’ environmental temperature needs in the sleeping zone (Shelton and Bnunm, 1986). Combining reduced nighttime temperatures with hovers or further reducing nighttime temperatures from the 6c‘ reductions suggested by Brumm and Shelton (1988) and Neinaber and Hahn (1989) offers the potential for even greater energy savings if pig performance is maintained in the nursery and subse quent growing-finishing performance is not affected adversely.

Materials and Methods

Two experiments were conducted at the University of Nebraska’s Northeast Research and Extension Center, Concord, to investigate differing reduced nocturnal regimens for weaned pigs. Seven hundred forty-four crossbred feeder pigs averaging 3 to 4 wk of age at the start of each trial (128 in each of the three trials of Exp. 1 and 120 in each of the three trials of Exp. 2) were used (Table 1).

Within 2 h of removal from the sow, locally purchased pigs (all from the same source within each trial) were weighed, eartagged, and sexed. They were transported by covered truck approximately 32 km and allotted by sex and weight-outcome groups to the two experimental treatments. Pigs were allotted to heavy and light initial weight groups to reduce weight variation within pens. For Exp. 2, dietary treatments were included in the alloca- tion.

Individual pig weights and feed consump- tion were obtained weekly during the nursery phase and biweekly during the growing- finishing phase of each experiment.

Nursery-Phase Facility Description

A two-room nursery was used for the nursery phase of the experiments. Each room had its own heating, ventilation, utility, and manure handling systems. Each room contained four (Exp. 1) or five (Exp. 2) 1.2-m x 2.4-m flatdeck pens with woven wire flooring and open mesh partitions. Further details of the facility have been described by Shelton and Brumm (1986).

Temperature control in the experimental treatment rmms in each trial was achieved using dual thermostats controlled by a switch- ing time clock. Thermostats in both rooms were equipped with capillary tubes having

sensing bulbs located at animal level just outside the pen area. After the initial random assignment, temperature treatments were alter- nated between rooms in each trial of each experiment. Air temperatures were measured and recorded hourly throughout each room and in the animal space using the methods described by Shelton and Brumm (1986, 1988).

Continuous, low-wattage lighting was provided by one 40-W incandescent light bulb located on the ceiling in the approximate center of each room. When workers were in the rooms, additional lighting was provided by three 100-W incandescent light bulbs. Light intensity levels were not measured.

Experiment 1

Exp. 1 consisted of three trials using 16 pigs per pen (.18 m2/pig) with one nipple waterer and two five-hole self-feeders per pen.

The hovers used in these trials formed a five-sided box and encompassed one-half of the pen area (Shelton and Brumm, 1986). Hover lids were constructed of 1.3-cm-thick flakeboard suspended from the pen frame (Figure 1). The lids were installed with a slight (2.5 cm) upward slope toward the front and were raised as the pigs grew to prevent damage by the animals. Initial height of the front of the hover lid was approximately 45 cm above the pen floor. Flakeboard (.6 cm thick) was

Figure 1. Sketch of flat-deck nursery pen with hover for modified reduced nocturnal temperatures (MRNT-H).

REDUCED NOCTURNAL "EMF'€?RATURES 1381

TABLE 1. INCLUSIVE DATES FOR EXPERIMENTS

Experimentandtrial Phase Weeks Dates 1

6 January 14 to February 25, 1987 February 25 to June 10,1987

March 27 to July 17,1987

orowing-finishing 18 March 10 to July 14.1988

1 Nursery

2 Nursery Growing-- l: February 27 to March 27,1987

3 Nursery 5 February 4 to March 10,1988 Growing-fdshig 16

2 1 Nursery 5 November 3 to December 8,1988

6 Gro~ing-finishing 19 Decem& 8 to April 20,1989

0 r 0 ~ Q - m 16 January 20 to May 19,1989

Growing-hnishing 16 March 14 to June 27,1989

December 9,1988 to January 20,1989 2 N-ry

3 N-ry 5 January 31 to March 14, 1989

attached to the outside of the mesh pen panels to form the rear and sides of the hover. A piece of .6 cm thick flakeboard was placed between the wire mesh flooring and pen support frame. This gave the hover a solid floor but placed all animals in direct contact with the same type of flooring material and prevented damage to the flakeboard.

Two regimens to manage air temperatures (target temperatures) were employed. The furnace thermostat in the room with the control treatment (CT) was set to maintain a dry-bulb temperature of 30'C during the 1st wk in each trial. Thereafter, the air temperature in the control treatment room was decreased 2c'/wk, in accordance with current recommendations (MWPS, 1983; Aheme et al., 1987).

Based on earlier work with similar hovers in the same facility (Shelton and Brumm, 1986), a 3c' temperature rise at animal level beneath the hovers was anticipated. Therefore, in the mom with the experimental treatment (modified reduced nocturnal temperatures with hovers, MRNT-H), an initial furnace thermostat setting of 27'C was selected to maintain an air temperature at pig level under the hover the same as CT during the 1st wk of each trial.

Beginning 1 wk after weaning, the daytime (0700 to 1900) furnace thermostat setting was decreased 2c'/wk, similar to CT. During nighttime hours (1900 to 0700), air temperature was to be reduced by 6c' from the daytime temperature. During the entire nursery

%omec, Merck and Co., Inc., Wway, NJ.

phase, pigs were offered a commercial, pelleted diet formulated to contain 1.15% lysine and 3,333 kcal/kg ME.

At the end of the nursery phase (approximately 17 to 19 kg live weight), pigs were moved to confinement growing-finishing facilities. The facility used in each trial was a mechanically ventilated building with six partially slatted pens (1.4 m x 4.9 m) on each side of a center alley. Further facility details have been reported by Brumm et al. (1982).

pigs were kept in the same group (pen) as in the nursery facility. Each pen of 16 pigs was provided .43 m2 of floor area, one nipple waterer and two threehole self-feeders. All pigs were treated for lice and mange6 within 2 wk after movement into the growing-finishing facility. Manually controlled water drippers were used for summer heat moderation.

For the first 2 wk after movement to the growing-finishing facility, the pigs were offered an 18% CP diet in Trials 1 and 2. Because of a feed mill mixing error, a 16% CP grower diet was offered in Trial 3. All pigs were offered a 16% CP growing diet for the next 6 wk, followed by a 14% CP finishing diet until termination of the trial. All diets were corn-soybean meal-based, contained 2.5% added fat and were offered in meal form. All pigs within the same trial received the same feed additive.

Experiment 2

Each of five flat deck pens in each nursery mom were divided into two 1.2-m x 1.2-m pens, for a total of 10 pens/mom. Each


TABLE 2. COMPOSITION OF ExpERzMENTAL DIETS (EXP. 2)

Item

Corn, No. 2 Soybean meal, 44% CP Dried edible-grade whey Condensed fuh solubles Dried brewer's yeast Tallow Dicalcium phosphate Limestone salt Copper sulfate Vit-w-Se mixabc LLysine HCl Antimicrobial premixd

Diet 1

41.10 28.85 20.00 2.50 1 .oo 3 1.30 .60 .30 .05 .30

1.00 -

2 3

63.95 50.40 27.50 27.75 5 .oo 15.00 - - - -

3 - 1.10 1 S O .80 .60 .30 .30 .05 .05 .30 .30 - .10 1 .oo 1 .00

Calculated analysis CP, % 19.1% 182 18.5 Lysine, 76 1.17 1.01 1.15 Ca, % .78 .68 .78 p, % .71 .60 .72 ME, kcavkg 3,230 3,227 3,318

'Provided the following minerals in the complete diet @pm): Zn, 75; Fe, 88; Mn, 30; Cu, 8.8; and I, 1.0. %ovided the following vitamins per kilogram of complete diet: vitamin A, 3,300 N; vitamin D, 550 IU; riboflavin,

2.2 mg; niacin, 17.6 mg; pantothenic acid, 9.9 mg choline chloride, 220 m g vitamin E, 11 mg; vitamin K, 2.2 mg, and vitamin B12, .022 mg.

'Provided .3 ppm SE as sodium selenite in the complete diet. dProvided 55 ppm carbadox in the complete diet.

pen housed six pigs (.24 m2/pig) with one nipple waterer and one three-hole self-feeder per pen.

The furnace thermostat in the control room was set identical to the CT treatment of Exp. 1. In the room with the 1OC' reduced nocturnal temperature (MRNT10) treatment, room air temperature was maintained the same as in the CT mom during the 1st wk postweaning and for 12 h/d (0700 to 1900) during subsequent weeks. During nighttime hours (1900 to 0700), starting 1 wk after weaning, the thermostat setting was reduced by 1 O c ' from the daytime temperature.

The experimental nursery diets investigated in this experiment are presented in Table 2. Dietary treatments were 1) 1.2% lysine diet (Diet 1) for 3 wk followed by 1.0% lysine (Diet 2) for the duration of the nursery trial and 2) 1.15% lysine diet offered continuously in the nursery.

At the end of the nursery period (19 to 20 kg live weight), pigs were moved to confinement growing-finishing facilities. All pigs within a trial were housed in the same facility. Pigs were assigned to pens based on weight-

outcome groups within temperature and diet treatments. There were two pens of 12 pigs each for each temperature and diet combma- tion in each trial. There were also two pens of pigs in each facility that were not monitored for performance during the growing-finishing phase.

The diet sequence during the growing- finishing phase was the same as that fed in Exp. 1. All diets contained carbadox (55 g/kg) until 34 kg live weight, followed by chlor- tetracycline (55 gkg) until 57 kg live weight and bacitracin methylene disalicylate (33 @g) until market. All diets contained 2.5% added fat for dust control.

Statistical Analysis

Statistical analyses were accomplished using the GLM procedure as outlined by SAS (1982). The pen of pigs was the experimental unit. The model for analysis of the nursery performance data has been presented by Bnunm et al. (1985) and used the temperature x trial interaction to test temperature effects.

REDUCED N 0 C l " A L TEMF'ERATURES 1383

2 e 10 - 3

0

i-'

c r -

0 -

-

-10

Tzmperatures During Exp. 1

/1,'~?i Week 3 Week I Week 5 We& 6

Results and Discussion

Enperiment I

The mean weekly air temperatures by hour of the day at animal levei, pooled across the three trials is shown in Figure 2. Target temperatures for the CT treatment were generally achieved, as were daytime (0700 to 1900) temperatures under the hovers for the MRNT- H treatment.

The time required to attain the daytime target temperature in the morning for MRNT- H was primarily a function of the output capacity of the heating system and was generally less than 2 h. The weaned pigs housed in the MRNT-H room, therefore, were exposed to the higher daytime temperatures for about 10 h/d beginning 1 wk after weaning and continuing for 3 to 5 wk. The rate of nighttime cool-down or temperature reduction in the

MRNT-H room depended on outside temperatures. Nighttime (1900 to 0700) target temperatures generally were not reached until the early morning hours, if at all, indicating that the pigs were exposed to the coolest air temperatures for a relatively short period. This was especially true during wk 4, 5 , and 6. During this period, nighttime air temperatures averaged 4.2c" warmer than the target temperatures.

From Figure 2, it is evident that pigs in the MRNT-H treatment were provided an air temperature under the hover that was approximately 3c" warmer than the corresponding room air temperature at animal level. The air temperature pattern for CT and MRNT-H under the hover follow closely those reported by Brumm and Shelton (1988).

Because no interactions between initial (weaning) weight and temperature were significant (P > .l), nursery performance data were

https://www.researchgate.net/publication/19759666_A_modified_reduced_nocturnal_temperature_regimen_for_early-weaned_pigs?el=1_x_8&enrichId=rgreq-4e291d4e-5003-4bfd-b3be-3da392797445&enrichSource=Y292ZXJQYWdlOzIxMDgzNTMyO0FTOjE4NTkyMDI2MzMwMzE3MUAxNDIxMzM4MjUzODM1

1384 BRUMh4 AND SHELTON

TABLE 3. EFFECT OF EXPERIMENTAL TEMPERATURE TREATMENTS ON WEANED PIG PERFORMANCE (NUF4SERY PHASE)

Id Weight, kg Initial P i e

Avg daily gain, k$' Avg daily feed, kg Feed/gaid No. dead or removed

Weighkkg -

Avg daily g a h kg Avg daily feed, kg Feed/gain No. dead or removed

2h

Initial Final

5.5 18.7 .31 5 0 1.58

1

6.5 19.1 .36 .59 1.65 3

5.5 18.3 .31 .49 1.61

0

- - - - - -

- - -

- -

-

6.6 1.93 .36 .6 1 1.69 3

6.5 17.0 .38 .52 1.39

0

5.9 20.5 .35 .58 1.66 1

6.5 16.2

.34

.50 1.45

0

- - - - - -

- - - - -

-

5.9 19.8 .33 .58 1.76 3

6.7 6.7 - 19.5 18.9 - .36 .35 - .56 .56 - 1.54 1.60 -

1 0 -

6.6 - 6.7 19.8 - 20.1 .38 - .38 .64 - .65 1.71 - 1.71 2 3 -

- .I5 <.01

.01

.02

-

- .4 .01 .01 .04 -

Bsixty-four pigstreatment -'.trial -1.

bCT = control temperature; MRNT-H = modified reduced nocturnal temperatures with hovers; MRNTlO = 1OC'

'Standard error of the mean. dsix weeks, t rid I; 4 wk, rial 2; 5 wk rial 3. ?emperatwe effect (P < .001). fTrial x temperature (P < .05). STemperature effect (P < .05). hFive weeks, Trials 1 and 3; 6 wk, Trial 2.

reduced nocturnal temperatures beginning 1 wk after weaning.

pooled and are presented by trial for the main temperature effect in Table 3. Pigs in the MRNT-H treatment weighed less (P < .001) than CT pigs at the end of each trial, even though a trial x temperature interaction (P < .05) was present for AM;. In Trial 1, there was no difference in ADG, whereas in both Trials 2 and 3 CT pigs numerically outgained MRNT-H pigs.

There was no effect (P > .lo) of MRNT-H on ADF for any time period reported. This differed from the results of B r u m and Shelton (1988) and Brumm et al. (1985), in which an increase in feed intake was noted for both a MRNT regimen similar to these trials and a reduced nocturnal temperature regimen imposed at weaning. The lack of increase in feed intake in these trials is not understood because air temperature patterns under the hovers for MRNT-H vs (2" compared closely to those of Brumm and Shelton (1988).

In a previous experiment that combined hovers and reduced nocturnal temperatures

imposed at weaning, we also observed no increase in feed intake (Shelton and Brumm, 1986). However, we concluded that the temperature reduction investigated may have been too severe, and we suggested that slightly increased temperatures under the hovers might have improved animal performance. The results of the experiment reported herein do not support this suggestion. When combined, the results of both experiments using hovers with reduced nocturnal temperatures indicate that pigs with access to hovers may react differently to their environment than pigs in pens with no hovers. In both experiments with hovers, the feed intake was the same with reduced gain, implying that heat loss of the pig was greater or the usage of feed energy was less efficient.

Data for total energy usage, propane and electricity usage, and utility costs during the three trials are summarized in Table 4. Reducing room air temperatures during daytime hours an average of 1.9c' and an average

REDUCED NOCTURNAL TEMPERATURES 1385

TABLE 4. TOTAL NURSERY UTILITY USAGE AND COSTS

Item

Experiment h4RNT-H TO^ energy, M J ~ Propane, liter Electricity, kwh

utility cost, $c Experiment m l 0

TOW energy, M J ~ Propane, liter Electricity, kwh

Utili& cost. F

50,202 37,113 - 1,908 1,406 -

$374.48 $277.61 - - 430 350

65,587 - 51,389 2,467 - 1,939

744 - 540 $490.40 - $385.68

~~

%3 = control temperatures; MRNT-H = modified reduced nocturnal temperatures with hovers; MRNTlO = 1OC'

bpropane: 25.5 MJfiteq electricity: 3.6 htJ/kwh. cPropane: $. 185fiter; elecuicity: $.05/kWh.

reduced nocturnal temperatures.

of 5.9c" during nighttime hours resulted in total energy, propane, and electricity savings of 26.1, 26.3 and 18.6%, respectively, when the MRNT-H temperature treatment was compared with the CT treatment. Utility energy usage was reduced by 68 UT and utility costs were reduced by $ S O (propane = $.185/liter; electricity = $.05/kWh) for each pig weaned with the MRNT-H regimen compared with CT. Weather patterns probably influenced the utility usage compared with normal conditions because outside air temperatures for all weeks of all trials (with the exception of the 1st wk of the third trial) were warmer than normal.

There were no nursery temperature regimen x trial interactions for growing-finishing performance. There also were no interactions between nursery temperature regimens and initial weight. Therefore, the data were pooled and results for the main effect of nursery temperature regimen are given in Table 5. Although the nursery temperature regimen of MRNT-H resulted in a .7-kg lighter (P c .001) pig entering the growing-finishing facility, there was no effect of nursery temperature regimen (P > .l) on ADG, feed intake, or feed conversion efficiency during the growing- finishing phase.

The overall death loss or removal rate of 6.3% for the MRNT-H pigs vs 2.6% for CT pigs was due to a tail biting episode in one pen of MRNT-H pigs in Trial 2, during which six pigs were removed from the experiment even though all pigs had been taildocked prior to weaning. There were no other differences between the treatments in death loss or

removal rate during the growing-finishing phase.

Experiment 2

Figure 3 presents a plot of the mean weekly air temperature by hour of the day at animal level, pooled across the three trials. Target temperatures for the (3 treatment were generally achieved, as were daytime (0700 to 1900) temperatures for the MRNTlO. Similar to Ekp. 1, the rate of nighttime

cool-down or temperature reduction in the MRNTlO room depended on outside temperatures. Nighttime (1900 to 0700) target temperatures usually were not reached until approximately 0400 to 0500 during wk 2, 3 and 4. The larger mass of pigs, combined with unusually warm outside air temperatures, generally prevented the M R N T l O room from reaching the desired nighttime temperature during wk 5 and 6.

Nursery performance data were pooled across initial weaning weight and are presented by trial in Table 3. There was no effect (P > .lo) of MRNTlO on overall daily gain, daily feed, or feedgain.

The significant trial x temperature interaction (P < .0005) for ADG during wk 0 to 1 was not due to a temperature effect because both rooms were similar ip temperature at pig height (Figure 3), and it probably reflects the normal variation in pig performance immedi- ately after weaning. The trial x temperature interaction (P e .0005) for ADG and feeagain wk 2 to 3 was caused by a decrease in gain for


TABLE 5. EFFECT OF NURSERY TEMPERATURE TREATMENTS ON SUBSEQUENT GROWING-FIMSHING PERFORMANCE

Nursery temperature (reatment Experimentanditem CP MRNT-P MRNTIOa SEI&

1 Weight Q InitialCd Final

Avg daily gain, kg Avg daily feed. kg FWgah No. dead or removed

5 18.5 17.8 - 92.4 92.4 - 1.0

.65 .66 - .02 1.96 1.96 - .03 3.02 3.01 - .01 5 12= - -

Weight, kg - 19.9 - Initial 19.7

Final 94.4 - 94.4 <.Ol .64 - .64 <.01

Avg daily feed. kg 2.14 - 2.13 <.01 Avg daily gain, 43

3.34 - 3.34 <.01 No. dead or removed 3 - 7 <.01 FWgain

%T = control temperature; MRNT-H = modified reduced nocturnal temperatures with hovers; h4RNTlO = 1oc'

bStandard error of the mean 'CT = 190 pigs; MRNT-H = 192 pigs. 9emperature effect (P < .OOI). eSix pigs m one pen removed from test in Trial 2 for severe tail biting.

reduced nocturnal temperatures beginning 1 wk after we-.

MRNTlO pigs in Trial 1 vs CT pigs, whereas in Trials 2 and 3, MRNTlO pigs had better gains than CT pigs. For the same wk 2 to 3 period, MRNTlO pigs had increased feed disappearance (P < .Ol) compared with CT pigs in all trials.

TABLE 6. EPPECT OF NURSERY DIET SEQUENCE ON WEANED PIG PERFORMANCE (Fim. 2)

Item and period, wk 112 3 SEMb

- Weight, kg Initial 6.4 6.4 3 wk 11.4 11.2 .1 P i 19.7 19.8 2

Oto3wk 24 .23 <.01 Overall .36 .36 <.Ol

Oto3wk .38 .37 <.01 Overall .61 .61 .01

Oto3wk 1.61 1.63 .03 o v d 1.70 1.69 .02

Avg daily gain, kg

Avg daily feed, kg

Feed/&

%et sequence hm Table 2. bStandard error of the menu.

Similar to MRNT-H pigs in Exp. 1, M R N T l O did not result in an increased disappearance of feed compaxed with control pigs. However, the colder nighttime tempexa- tures did not reduce gain, significantly worsen feed/gain, or alter the number of pigs that died or were removed from the experiment.

Brumm et al. (1985) reported that a 1OC' reduced nocturnal temperature regimen imposed at weaning beginning with a 4-d adaptation period significantly increased feed intake and gain for pigs housed 16/pen in the same facilities. Waiting 1 wk to reduce nighttime temperatures a similar amount in these trials did not give the same pig response.

The lack of a feed intake response to MRNTlO agrees also with the recent variable results of Neinaber and Hahn (1989). These authors reported no increase in feed intake or daily gain for a 6c" reduced nocturnal regimen imposed 5 d after weaning in one trial but showed a significant improvement (P < .05) in these performance traits in a second trial. These authors also reported no effect on pig heat production or neutrophiklymphocyte ratio in the first trial. In their second trial, no difference in pig heat production was measured, although the improved pig performance

REDUCED NOCTURNAL TEMPERATURES 1387

Animal Level Temperatures: CT MRNTlO .-___--_

Temperatures During Exp. 2

1111

Wcek 3 Wcek 4

I \ I 'c

n Week 5

7 a.m. ' J p.m. I a.m. 7 p.m. I a.m. 7 p.m. 7 a.m. I p.m. 7 a.m. I p.m. 7 a.m. 7 p.m.

Hour of Day by Week

Figure 3. Mean weekly air temperature by hour of the day at animal level and outside during nursery phase of Exp. 2. CT = control temperatures; MRNTlO = modified reduced nocturnal temperatures (reduced 1OC').

was accompanied by an increased (P < .01) neutrophiklymphocyte ratio.

The use of a MRNTlO temperature regimen did result in a 22% savings in overall energy usage (Table 4). Utility energy usage was reduced by 79 UT and utility costs were reduced by $.58 (propane = $.185/liter; electricity = $.05/kWh) for each weaned pig in MRNTlO compared with m.

The nursery diets investigated had no effect (P > . l ) on overall nursery ADG, average daily feed, and feedgain (Table 6). The 1/2 diet sequence closely parallels the recommended 1.W.95 lysine levels for pigs from 5 to 10 kg and 10 to 20 kg (NRC, 1988). The lack of response to Diet 3 and the lack of a diet x temperature interaction suggests the nutritional needs of the -10 pigs were not different from the CT pigs.

Similar to Ekp. 1, there were no interactions between trial and nursery treatments for

growing-finishing performance. Therefore, the data were pooled across trials and are presented for the main nursery temperature treatments in Table 5. There was no effect (P > .lo) of either nursery temperature regimen or nursery diet regimen on subsequent growing- finishing performance.

implications

Contrary to many previously repoaed experiments using reduced nighttime temperatures, in these experiments weaned pigs did not respond to the reduced nocturnal temperature regimens by increasing feed intake. However, the fact that there was no negative effect on overall nursery or growing-finishing perfom- ance suggests that the weaned pig, under the housing and management conditions of these experiments, is much more tolerant of lower nighttime temperatures in the pig zone than the


generally accepted lower critical temperature, provided that daytime temperatures in the pig zone equal or exceed the lower critical temperature. Yet to be answered is the question of how short a time period of temperatures in the thermal-neutral zone is sufficient to support satisfactory pig performance.

Literature Cited

Aherne, P., M. Hogberg and H. W. Jones. 1987. Manage- ment and nutrition of the newly weaned pig. PIH-111, Coop. f i t . Sew., Purdue Univ., West Lafayetre, IN.

Brumm, M. C., E. R. Peo, Jr., S. R. Lowry and A. Hog. 1982. Effect of source of pig, housing system and receiving diet on performance of purchased feeder pigs. J. Anim. Sci. 55:1264.

Brumm, M. C. and D. P. Shelton. 1988. A modified reduced nocturnal temperature regimen for early-weaned pigs. J. Anim. Sci. 66:1067.

Brumm, M. C., D. P. Shelton and R K. Johnson. 1985. Reduced nocturnal temperatures for early weaned pigs. J. Anim. Sci. 61552.

C u t i s , S. E. and G. L. Monis. 1982. Operant supplemental heat in swine nurseries. In: Livestock Environment Ll.

Publ. 382. Am. Soc. Agric. Eng., St. Joseph, MI. Momson, W. D., E. Amoyt, I. McMillan, L. Otten and

D.C.T. Pei. 1987. Effect of duration of reward upon operant heat demand of piglets receiving microwave or iufrared heat. Can. J. Anim. Sci. 67:903.

Morrison, W. D., K. L. Laforest and I. McMillan. 1989. Effect of group size on operant heat demand of piglets. Can. J. Anim. Sci. 6923.

M W P S . 1983. Swine Housing and Equipment Handbook MWF'S-1. Midwest Plan Service, Ames. IA.

Neinaber, J. A. and G. L. Habn. 1989. Cool nighttime and weaning age effects on 3 to 10 week old pigs. Trans. ASAE 32(2):691.

NRC. 1988. Nutrient Requirement of Swine (9th Ed.). National Academy Press, Washington, DC.

SAS. 1982. SAS User's Guide: Statistics. SAS Inst., Inc., Gary, NC.

Shelton, D. P. and M. C. Bnunm. 1986. Energy management in a swine nursery using reduced temperatures, hovers, and reduced nocturnal temperatures. Trans. ASAE 29(6): 172 1.

Shelton, D. P. and M. C. Bnunm. 1988. Reduced nocturnal temperatures in a swine nursery-a modified regimen. Trans. ASAE 31(3):888.

Swinkels, J.W.G.M., E. T. Komegay and M.W.A. Verste- gen. 1988. The effect of reduced nocturnal air temperature and feed additives on the performance, immune response and scouring index of weanling pigs. J. Anim. Physiol. h. Nutr. 60:137.

two reduced nocturnal temperature regimens for early-weaned pigs

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