The effects of supplementary light on the behaviour and performance of calves

Applied Animal Behaviour Science, 30 ( 1991 ) 27-34

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Elsevier Science Publishers B.V., Amsterdam

The effects of supplementary light on the behaviour and performance of calves L. Weiguo* and C.J.C. Phillips** School of Agricultural and Forest Sciences, University College of North Wales, Bangor, LL57 2UW (Gt. Britain) (Accepted for publication 6 August 1990)

ABSTRACT Weiguo, L. and Phillips, C.J.C., 1991. The effects of supplementary light on the behaviour and performance of calves. Appl. Anita. Behav. Sci., 30: 27-34. Thirty calves of average age 139 days were allocated to a natural photoperiod of 10.5 h daylength (Treatment N), supplementary light in the bedding area to give 18 h daylength (Treatment S), or a choice between natural daylength or continuous light in the bedding area (Treatment SN). Supplementary light had no significant effect on calf weight gain, but it reduced daily standing time and the amount of walking in the bedding area and increased daily standing time in the feeding area. Calves in Treatment SN preferred the lit area for 58% of the time, and increased their daily lying time and decreased the standing time in the lit area. The experiment provides evidence that calves prefer a lit environment, and that supplementary light decreases their daily activity levels.

INTRODUCTION

Research by Peters et al. ( 1978, 1981 ) has demonstrated that supplementing natural daylength in autumn (when daylength declines from ~ 12 to 9 h day -~ ) with artificial light to give a total of 16 h of light will increase milk yield by 7-10%. Under similar circumstances Bodurov (1979) and Phillips and Schofield (1989) obtained increases of 14 and 16%, respectively. However, in a multi-farm study, Stanisiewski et al. ( 1985 ) found that although on average milk yield was increased by 8%, the response on individual farms was variable. In beef cattle some, but not all experiments have shown increased growth rates with supplementary light in winter (Peters et al., 1978, 1980; Roche and Boland, 1980; Tucker et al., 1984). The increase in cattle production is accompanied by, but not caused by, an increase in feed intake, as cattle on restricted feeding still exhibit increased productivity (Bilodeau et al., 1989). *Present address: Xinjiang August 1st Agricultural College, Wurumqi, China. **Author to whom correspondence should be addressed.

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L. WEIGUOAND C.J.C. PHILLIPS

Recently, on finding that supplementary light reduced daily activity levels and increased lying time in dairy cows housed in an environment where a large production response was obtained, Phillips and Schofield (1989) proposed that improved welfare a n d / o r reduced maintenance requirements may be responsible for productivity increases. Some hormonal evidence is available to support the theory that welfare is improved. Leining et al. (1980) recorded reduced glucocorticoid levels in light-supplemented bulls, suggesting reduced stress in these animals. Some preference for a lit rather than an unlit environment is known to exist in calves and sheep (Baldwin and Start, 1981), pigs (Baldwin and Meese, 1977) and both nocturnal and diurnal monkeys (Jacobs, 1977 ). This experiment was designed to confirm and extend this behavioural observation and to examine the preference of cattle for a lit or unlit environment. Research by Baldwin and Start ( 1981 ) showed that individually crated calves activating a light switch when standing, preferred a lit environment for 67% of the time, but this could obstruct the effect of supplementary light on lying behaviour. Preference tests in a group-housed situation with cattle given access to a lit or unlit chamber would overcome this problem. ANIMALS, MATERIALS AND METHODS

Fifteen Friesian, 10 Friesian × Limousin and 5 Belgian Blue calves ( 12 male and 18 female), which were on average 139 days old (SE 2.4) and weighed 128 kg (SE 2.6) at the start of the experiment, were allocated to triads according to liveweight, age, breed and sex. One calf from each triad was then allocated at random to three treatment groups: ( 1 ) N, natural daylight only; (2) S, natural daylight plus supplementary light in the bedded area between 06:00 and 24:00 h; (3) SN, natural daylight plus supplementary light in one half of the bedded area for 24 h. The three groups were housed in three pens each 4.3 X 6.5 m with a bedded area 4.3 × 3.7 m and a feeding area with a frontal barrier for silage and concentrate feeding. Each bedded area was divided into two with a 1.5-m wall so that a choice of supplementary light or no supplementary light could be applied in Treatment SN. The bedded areas were provided with straw bedding at weekly intervals and were covered with a portal-framed building with enclosed sides and light-proof partitions between each pen and between the two halves of the choice areas in Treatment SN. A single 2.35-m fluorescent tube (125 W) was suspended from the roof at a height of 3.2 m to provide the supplementary light to each half of the bedded area in Treatment S and one half of the area in Treatment SN. The feeding area was not covered or lit and was scraped once weekly. Calves were group fed grass silage ad libitum and 2 kg concentrate per head. Natural daylight intensity was recorded in the bedding areas at two heights

EFFECTS OF LIGHT ON CALVES

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( 30 cm, the head height of a calf lying down and 80 cm, head height of a calf standing), using a six-direction cube measuring technique (Smith, 1989 ) with a photometer (R102 Macam, Photometric Ltd., Livingston, Scotland) at 1 m 2 intervals. For 0 and 100% cloud cover, mean light intensities were 6333 and 338 lx at lying height and 1948 and 266 lx at standing height, respectively. Temperature was recorded in the centre of each bedded area at a height of 1.5 m and averaged 12.2°C ( ( m a x i m u m + m i n i m u m ) / 2 ) . During the experiment, average sunlight duration was 179 min day-1, cloud cover was 73% and wind speed at the feeding barrier was 2.8 m s-1. Differences between pens in all climatological factors were small, but to counteract any pen effects on behaviour the treatments were switched between pens half way through the 10-week experiment. Calves remained on the same treatment throughout. Natural daylength increased from 8 h 45 min to 13 h 25 min during the experiment and averaged 10 h 32 min. Mean intensities of the supplementary light at 80 and 30 cm were 58 and 42 Ix, respectively. Silage dry matter (DM) intakes were recorded daily and calves were weighed seven times at approximately 10-day intervals, with liveweight gain being calculated by regression.

Behaviour recording Calf behaviour in the bedded area was recorded by an infrared sensitive video camera (Panasonic WV-1450) which was mounted from the ceiling, together with a 125 W infrared illuminator (Badger 500 Mk3), and connected to a time-lapse video-cassette recorder (Panasonic AG6010). Videotapes were replayed and which calves were standing or lying in the area at 5min intervals, and the number of incidents of walking, change of lying position, grooming (self or other calf) and agonistic behaviour ( m a x i m u m one recording per 5 min period) were recorded. Several days were recorded per treatment in Weeks 4 and 5 and one 24-h period was selected for analysis with identical climatological characteristics for each treatment (0% cloud cover, negligible wind run). Calf behaviour in the feeding area was recorded by direct observation during one 24-h period in Week 6. At intervals of 15 min, calves in this area were recorded as feeding or standing. Incidents of grooming (self or other calf) were also recorded ( m a x i m u m of one recording per 15 min period). A 1.5-W hand torch was used to aid identification in the dark.

Stat&tical analysis Weight gain and all behaviours were analysed by one-way analysis of variance which also removed block effects, using the statistical package Genstat (Lawes Agricultural Trust, 1980). For Treatment SN the preference to perform behaviours in the lit or unlit part of the bedded area was examined using

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L. WEIGUOANDC.J.C. PHILLIPS

Z 2 tests. T h e t w o p a r t s o f t h e b e d d e d a r e a w e r e o f s l i g h t l y d i f f e r e n t a r e a ( 5 6 a n d 44% ) a n d results in T a b l e 1 are a d j u s t e d p r o p o r t i o n a t e l y to allow for this.

RESULTS

Calves in Treatment N tended to consume more silage DM (2. l 1 kg compared with 1.99 kg for Treatments S and SN). Liveweight gain was not affected by treatment (0.79, 0.76 and 0.77 kg day -I for Treatments N, S and SN, respectively, standard error of the difference between two means, 0.053 ).

Behaviour in bedded areas

There were no significant differences in daily lying time (Table 2 ) but calves in Treatment S tended to spend less time lying between 19:00 and 01:00 h ( P = 0 . 1 6 ) than those in Treatment N. Standing time tended to be least in Treatment S, this difference being most pronounced between 09:00 and 20:00 h ( P = 0.04). Calves in Treatment N showed more incidents of walking than those in Treatments S or NS. There was no significant difference in the number of incidents of grooming self, agonistic behaviour or changing lying position, but there was a trend towards less grooming of other calves in Treatment S. TABLE 1 Behavioural preferences in Treatment SN

Time spent (min day- i Lying Standing Total Incidences (no. per 24 h) Walking Grooming (self) Grooming (other) Agonistic behaviour Change in lying position

With supplementary light

Without supplementary light

•2

p1

440 99 539

317 136 453

20.0 5.8 7.5

<0.001 <0.05 <0.01

1.7 0.0 0.0 4.5 0.1

>0.05 >0.05 >0.05 <0.05 >0.05

20 9.4 2.0 1.5 1.1

~Probability that treatment effects are not different.

29 9.6 1.6 8.1 0.7

EFFECTSOF LIGHT ON CALVES

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TABLE 2 Calfbehaviour in bedded area Treatment

Time spent (rain per 24 h) Lying Standing Total

N

S

SN

774 247 1021

766 180 946

758 234 992

Incidences (no. per 24 h) Walking Grooming (self) Grooming (other) Agonistic behaviour Change in lying posinon

56.2 a 17.4 4.5 12.3 2.8

44.90 16.5 2.4 10.4 3.1

SED l

p2

125.5 32.2 137.1

0.99 0.12 0.86

49.3 b 19.0 3.6 9.6 1.8

4.02 4.96 1.11 2.45 0.78

0.04 0.88 0.19 0.54 0.24

IStandard error of the difference between two means. ~Probability that treatment effects are not different. Means with different superscripts differ significantly ( P < 0.05) by Student's t test.

Behavioural preferences in Treatment S N Calves spent more time lying and less time standing in the half of the pen with supplementary light (Table 1 ). In total more time was spent in this half of the pen than in the half without supplementary light. There was a tendency (not significant ) for calves to have fewer incidents of walking in the half with supplementary light, and a significant reduction in agonistic behaviour in this half. Grooming and the number of lying position changes were not affected by treatment. TABLE3 Calfbehaviour in feeding area Treatment

Time spent (min per 24 h) Feeding Standing Total Incidences (no. per 24 h) Grooming (self) Grooming (other)

N

S

SN

287 51 u 338

290 92 a 381

261 71 ab 332

0.5 0.1 b

0.5 0.7 a

0.3 0.2 b

SED ~

p2

29.2 13.9 31.7

0.57 0.03 0.26

0.32 0.23

0.77 0.04

l Standard error of the difference between two means. 2probability that treatment effects are not different. Means with different superscripts differ significantly ( P < 0.05 ) by Student's t test.

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L. WEIGUO AND C.J.C, PHILLIPS

Behaviour in feeding area

There was no significant difference in feeding time between treatments (Table 3). Calves in Treatment S spent more time standing than calves in Treatment N. Few grooming incidents were recorded in the feeding area, but significantly more were recorded between calves in Treatment S. DISCUSSION

The absence of any significant effect of supplementary light on calf weight gain was not unexpected, as any improvement is likely to be between 1 and 20% (Peters et al., 1978, 1980) which would not be detected with the number of animals used in this study. The results confirm the finding of Phillips and Schofield (1989), that supplementary light reduces the amount of walking activity in cattle, although the ratio of unsupplemented to light-supplemented activity rates in this experiment ( 1.25 : 1 ) is not as great as in Phillips and Schofield ( 1989 ) ( 1.50:1 ). Phillips and Schofield ( 1989 ) also recorded an increase in lying time of ~ 20%, which was not recorded in this experiment, and was not recorded in the experiments of Nicks et al. ( 1988 ) and Dechamps et al. ( 1989 ). There are several possible reasons for the reduced effects in this experiment. Firstly, the environment used in this experiment was more benign than the cubicle building employed by Phillips and Schofield (1989). Lying times (min day -l ) in this experiment and in that of Phillips and Schofield (1989) were 766 and 772, respectively, for Treatment S and 774 and 624, respectively, for Treatment N, suggesting that lying time was below the preferred level in the cubicle shed of Phillips and Schofield ( 1989 ) when no supplementary light was given. Schmisseur et al. ( 1966 ) found that cows lay down for 741 and 640 min day- 1 in a straw yard and cubicle shed, respectively, supporting this theory. Secondly, juveniles were used in this experiment whereas Phillips and Schofield (1989) used cows, which are known to show a high preference for maintaining lying time (Metz, 1984), and Nicks et al. ( 1988 ) and Dechamps et al. (1989) used bulls. In the only known comparison of activity levels between cattle types in the same environment, Hall ( 1989 ) found that bulls had a higher ratio of standing to lying time than cows but there was no difference in walking time. Thirdly the light intensity used in this experiment was less than that used by Phillips and Schofield (1989) (218 and 418 lx, respectively, when measured by the method of Phillips and Schofield ( 1989 ) ). Behavioural preferences in Treatment SN show that calves chose to spend more time lying in a lit environment. The question arises as to whether they preferred the lit environment to the unlit one, with lying time naturally being increased as this takes up a major part of the calf's day, or whether supple-

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33

mentary light per se had an effect on the calf that caused it to lie down in that environment for longer, without necessarily preferring it. The absence of any difference in lying time between Treatments N and S favours the first hypothesis, although some effect of supplementary light on activity levels must be acknowledged, as a result of changes in standing and walking levels in this experiment and that of Phillips and Schofield (1989). Indeed, the fact that calves with supplementary light reduced their standing time in the lit area but increased it in the outside (unlit) area, suggests motivation for this behaviour. The effects of supplementary light on the behaviour of cattle during the period of supplementation seem now to be well established. During the actual period of the day that supplementary light was applied in this experiment, lying time was reduced and the peak of feeding behaviour was delayed by 1 h. Dechamps et al. (1989) found that standing time was increased during the actual period of supplementation, and Phillips and Schofield (1989 ) found that the increased standing time was in the feeding, rather than the lying area, in accordance with results obtained in this experiment. In conclusion, supplementary light did not affect the lying time of calves but it did reduce activity levels and time spent standing. Evidence shows both that calves prefer a lit environment and that supplementary light per se has modifying effects on activity levels. ACKNOWLEDGEMENTS

The authors are grateful to N. Kenyon, H. Omed and J. Ffridd for help in conducting the experiment. One of us (L.W.) is indebted to the Chinese Government for a Visiting Lecturer Scholarship.

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Jacobs, G.M., 1977. Brightness preference in nocturnal and diurnal South American monkeys. Folia Primatol., 28: 231-240. Lawes Agricultural Trust (LAT), 1980. Genstat Mark 4.03. Rothamsted Experimental Station, Harpenden, Gt. Britain. Leining, K.B., Tucker, K.A. and Kesner, J.S., 1980. Growth hormone, glucocorticoid and thyroxine response to duration intensity and wavelength of light in prepubertal bulls. J. Anita. Sci., 51: 932-942. Metz, J.H.M., 1984. The reaction of cows to short-term deprivation of lying. Appl. Anim. Behav. Sci., 13: 301-307. Nicks, B., Dechamps, P., Canart, B. and Istasse, L., 1988. Resting behaviour of Friesian bulls maintained in a tie-stall barn under two patterns of lighting. Appl. Anim. Behav. Sci., 19: 321-329. Peters, R.R., Chapin, L.T., Leining, K.B. and Tucker, H.A., 1978. Supplemental light stimulates growth and lactation in cattle. Science, 199:911-912. Peters, R.R., Chapin, L.T., Emery, R.S. and Tucker, H.A., 1980. Growth and hormonal response of heifers to various photoperiods. J. Anita. Sci., 51:1148-1153. Peters, R.R., Chapin, L.T., Emery, R.S. and Tucker, H.A., 1981. Milk yield, feed intake, prolactin, growth hormone, and glucocorticoid response of cows to supplemental light. J. Dairy Sci., 64: 1671-1678. Phillips, C.J.C. and Schofield, S.A., 1989. The effect of supplementary light on the production and behaviour of dairy cows. Anim. Prod., 48: 293-303. Roche, J.F. and Boland, M.P., 1980. Effect of photoperiod in winter on growth rate of Friesian male cattle. Ir.J. Agric. Res., 19: 85-90. Schmisseur, W.E., Albright, J.L., Dillon, W.M., Kehbert, E.W. and Morris, W.H.M., 1966. Animal behaviour response to loose and free-stall housing. J. Dairy Sci., 49: 102-104. Smith, A., 1989. Measurement of light intensity. In: C.J.C. Phillips and J.M. Forbes (Editors), Photoperiodic Manipulation of Cattle Production. Proceedings of a Workshop, 6 September 1989, University College of North Wales, Bangor, Dairy Research Unit, Tech. Rep. No. 4, pp. 27-29. Stanisiewski, E.P., Mellenberger, R.W., Anderson, C.R. and Tucker, H.A., 1985. Effect of photoperiod on milk yield and milk fat in commercial dairy herds. J. Dairy Sci., 68:1134-1140. Tucker, H.A., Peticlerc, D. and Zinn, S.A., 1984. The influence of photoperiod on body weight gain, body composition, nutrient intake and hormone secretion. J. Anim. Sci., 59: 16101620.