Variation in the Level of Grain Defect Light Flecks and Spots on Cattle Hides
© The Author(s) 2001
Received: 01 February 2000
Accepted: 26 September 2000
Published: 31 March 2001
The occurrence of hide damage light flecks and spots was determined on tanned hides from 28 herds during a period of 8 to 12 months. Light flecks and spots are described as small areas of grain loss up to 3 mm in diameter that are seen on dyed crust cattle leather. Damage was found on 75.8% of all hides. The neck and shoulders were the anatomical region with the highest prevalence of damage. Sixty-eight per cent of all hides had light flecks and spots in this region. The forelimbs and dewlap were the anatomical region with the second highest occurrence with a prevalence of 39.1%. This distribution corresponded to the known distribution of lice in cattle. No significant differences were observed in age, sex, prevalence of lice in the herd assessed in March or infestations with different lice species. The frequency of light flecks and spots varied significantly during the year. The frequency was highest in the late winter and early spring, decreased significantly during the summer and was lowest in the autumn. This variation supported the importance of lice in the development of light flecks and spots and suggested a relatively long healing period for the damages induced by lice.
Variasjoner i forekomsten av narvfeilen lyse flekker og prikker på storf.
Hudene fra 28 storfebesetninger ble samlet inn gjennom en periode på 8 til 12 måneder for å kartlegge forekomsten av skaden lyse flekker og prikker på hudene etter garving. Totalt inngikk 368 huder i undersøkelsen. Skaden lyse flekker og prikker er definert som kratre i overflaten eller narven på storfelær med en diameter på inntil 3 mm. Hudene ble kromgarvet og vegetabilsk ettergarvet til annilinlær og undersøkt før siste overflatebehandling av læret. Skaden lyse flekker og prikker ble påvist 75,8% av alle huder. Nakke og skulder var den anatomiske region med høyest forekomst av skaden (67,9%) etterfulgt av bog og dogglapp (39,1%). Dette utbredelsesmønsteret samsvarer godt med predileksjonsstedene for lus hos storfe. Det var ingen signifikant kjønnseller aldersforskjell i utbredelsen av skaden. Det var heller ingen signifikant forskjell i forekomsten av skader på hudene mellom besetninger som hadde en høy prevalens av lus mål i mars måned og besetninger som hadde en lav prevalens av lus på dette tidspunktet. Besetninger som var infisert av både blodlus (Linognathus vituli) og pelslus (Damalinia bovis) hadde samme forekomst av skader som besetninger som hadde rene pelslusinfeksjoner. Det var en signifikant sesongmessig variasjon i forekomsten av skaden lyse flekker og prikker, forekomsten var høyest hos dyr slaktet fra januar til april, deretter ble kvaliteten gravis bedre utover sommeren og høsten. På bakgrunn av disse resultatene konkluderes det med at det er en sikker sammenheng mellom lus og skaden lyse flekker og prikker på læret. Pelslus (D. bovis) er en viktigere årsak enn blodlus (L. vituli), på bakgrunn av at det ikke var noen tilleggseffekt av blandede infeksjoner sammenlignet med rene pelslusinfeksjoner. Den aldersuavhengige forekomsten av skaden sammenhold med kjent kunnskap om at lus i særlig grad forekommer hos kalver og ungdyr, indikerer en lang avhelingstid. På den andre siden kan den sesongmessige variasjonen indikere at en delvis avheling kan inntre i løpet av 2 til 3 måneder.
Several ectoparasites can be responsible for damage of cattle hides . Some of the damage is very specific, such as grub damage caused by warble fly larvae, but most ectoparasite damage is more nonspecific. In recent years, light flecks and spots have been considered the main damage caused by ectoparasites.  found a significant association between both biting lice (Damalinia (Bovicola) bovis (Linneaus 1758)) and sucking lice (Linognathus vituli (Linneaus 1758)) and light flecks and spots on leather. These investigators described light flecks and spots as small areas of grain loss up to 3 mm in diameter that are seen on dyed crust leather . This damage was reported to be a major problem for the hide industry in Great Britain for the first time in 1983 and has later been reported to be a problem in Holland, Scandinavia, USA and New Zealand . Tanners from Nordic countries found light flecks and spots on 50%–55% of Norwegian cattle hides in 1991, and the problem was estimated to cost the Norwegian cattle industry 24–25 mill NOK each year (Dørum personal communication). The aim of this paper is to describe the variation in the frequency of light flecks and spots damage on the hides from cattle not treated for ectoparasites.
Materials and methods
A prospective cohort study was performed in 33 herds during a period of two and a half years from 1. January 1994 to 30. June 1996, with animals leaving or entering the herds at any time. Twenty-eight of the herds were treated for lice between September and December 1994. Five of the herds took part in a pilot study for the eradication programme in December 1993. Hides were collected from all herds during the whole study, in order to assess the frequency of damage in hides from untreated and treated animals. The results in the present paper are based on hides collected from the 28 herds in the main group before the start of the lice eradication programme.
The selection criteria, the prevalence of lice in the herds and the clinical examination procedure used in the herds are described previously . D. bovis was present in 27 of 28 herds and in 27% of the animals. L. vituli was present in 11 of 28 herds and in 5% of the animals. At least one of these louse species was present in all the herds. In a few of the herds, other ectoparasite species known to affect the hide quality were also present. Four of the herds had clinical signs of tail mange (Chorioptes bovis (Herning 1845)), and the diagnosis was confirmed in laboratory examination. Two of the herds were in the distribution area of Ixodes ricinus (Linnaeus 1758). A total of 368 hides sampled from the period before treatment were included. The mean number of hides from each herd was 13.1 with a variation from 2 to 21.
Examination of the hides
The hides were tanned in a commercial tannery and evaluated as aniline dyed crust leather.
Score 0: No damage.
Score 1: Slight damage, with 1–2 light flecks or spots per 100 cm2.
Score 2: Some damage, with 3–5 light flecks or spots per 100 cm2.
Score 3: Severe damage, with more than 5 light flecks or spots per 100 cm2.
Light flecks and spots were defined as small areas of grain loss up to 3 mm in diameter .
All 8 evaluations from 1 hide were used to determine an overall parameter termed the maximum score. The maximum score was defined as the highest single evaluation in 1 hide. In the statistical analyses the ectoparasite diagnoses were defined at herd level. Total lice prevalence was defined as the prevalence of both D. bovis and L. vituli. All analyses were made in Statistical Analysis System . A Spearman rank correlation test was used for testing seasonal variations. Otherwise, statistical hypothesis testing was undertaken using t-test. The statistical testing was based on the frequency of hides without damage (maximum score 0).
Frequency of hides with light flecks and spots and the frequency of damage within anatomical regions (n= 368).
Neck and shoulders
Forelimbs and dewlap
Rump, hindlimbs, sides and belly
Effects of age and sex
Frequency of hide damage in cows divided in age classes at the time of slaughter.
Age in months
Number of hides
Frequency of hide damage in bulls divided in age classes at the time of slaughter.
Age in months
Number of hides
Effects of high and low prevalence of lice assessed in March
Frequency of hide damage according to lice prevalence in the herd in March 1994.
Number of hides
Average prevalence of lice in March
Hides from herds with lowest prevalence.
Hides from herds with highest prevalence.
Effects of biting lice compared with the effect of mixed infections
Frequency of hide damage in herds infested with biting lice compared with herds infested with biting lice and sucking lice.
Number of herds
Number of hides
Biting lice infections
Seasonal variations in the frequency of light flecks and spots
Seasonal variations in the frequency of damaged hides.
Number of hides
 and  described light spots as small areas of grain loss of 1–3 mm in diameter and light flecks as spots of less than 1 mm in diameter seen on dyed crust bovine leather. These investigators found a significant connection between the occurrence of the 2 types of damage and concluded that the 2 defects had a common cause.
Light flecks and spots were found on 75% of all hides in this study. In 1991, Nordic tanners found lice related damage on 50%–55% of all Norwegian hides (Dørum, personal communication). This investigation was based on a commercial evaluation of finished leather and is not directly comparable to the present investigation. The results in the present study were based on the number of flecks and spots found on dyed crust leather. Older damage could have received a different assessment if the hides had been examined at a later stage in the tanning process. The finishing of the leather may mask small and very superficial grain damage. Thus, given this different assessment, these 2 reports suggest about the same level of light flecks and spots. The quality of the hides in the present study should, in the light of the selection criteria, be comparable to the average of Norwegian cattle hides. In a smaller survey from April 1998, light flecks and spots were present on 44% of the hides (Nafstad, unpublished data). Two hundred hides from abattoirs all over the country were included in this study. The animals were slaughtered in March and April when the lice population is at its highest. The hides were tanned and examined after the same procedure as in the main study. The use of insecticides increased significantly from 1990 to 1996 , which probably explain the improvement in hide quality observed in the 1998 survey.
The neck and shoulders were the anatomical region with the highest prevalence of light flecks and spots, followed by the forelimbs and dewlap and the back. This distribution corresponded well with the predilection sites for lice [4, 7] and supported the hypothesis that lice are the main cause of light flecks and spots. Damage associated with other ectoparasites such as Demodex bovis (Stiles 1892), or I. ricinus would have given a different distribution. Ticks mostly affect the belly region and demodicosis the forelimbs and dewlap [18, 19].
 and  stated that severe lice infestations were responsible for hide and leather damage caused by secondary bacterial infections or scratching behaviour.  found an association between lice and light flecks and spots and suggested that inflammation caused by the lice infestations was the most probable mechanism responsible for this damage. Light flecks and spots were reported to be a major quality problem for cattle hides in Great Britain around 1983. This increase in light flecks and spots took place at the same time as the national eradication programme for warble fly was altered. Systematic treatment with organophosphorous insecticides was changed to a combination of movement restrictions and treatment in affected districts only . A side effect of the systematic treatment was control of lice, and the lice population probably increased as a result of the changes in the eradication programme.
Light flecks and spots or similar damage have also been associated with various tick species and Psoroptes ovis (Hering 1838) infestations in cattle [10, 8, 14]. With the exception of I. ricinus, these parasites do not occur in Norway and can not explain the present level of light flecks and spots. It has been suggested that stable fly Stomoxys calcitrans (Linnaeus 1758) can cause light flecks and spots (Bugby personal communication). However, more work is needed to determine whether stable fly may cause light flecks and spots, in addition to lice, under Norwegian circumstances. In an experimental study,  found no obvious change in the leather to be caused by D. bovis and only dilated hair pores to be caused by L. vituli. In the same study, these authors found inflammatory reactions in the raw hides similar to the changes reported by . This discrepancy suggested that the tanning method influences the grain damage shown after tanning.
The results in the present study did not vary with sex and age of the animals. This result was surprising given the age distribution of lice infections. Calves and young animals have the highest prevalence and heaviest infestations of lice [5, 6, 13], and consequently a significantly higher occurrence of light flecks and spots among calves and young animals could be expected. For the same reason, the difference between cow and bull in the average age at slaughter should have given a difference in occurrence of light flecks and spots. The absence of the expected age variation in the occurrence of the damage may have been influenced by a long and not exactly known healing period for the damage.  suggested a healing period of more than 12 months.  found only very slight damage 9 weeks after treatment of lice. The expected age variation may also have been disturbed by light flecks and spots caused by ectoparasites other than lice.
The frequency of light flecks and spots showed no significant association with the prevalence of lice in the herds in March. The reason for this lack of association may be that one examination did not give a representative description of the lice situation in the herd and the fact that light flecks and spots also may be caused by other ectoparasites.
Hides from herds with mixed lice infections had the same prevalence of light flecks and spots as hides from herds with only biting lice infections. This result corresponded with the result of Bugby & Webster (1994), who found no additive effects of mixed infections compared with only biting lice on the frequency of light flecks and spots. These results showed the importance of D. bovis for the development of light flecks and spots.
The seasonal distribution of the lice population is well known. The population increases during the winter, decreases with the shedding of the winter coat in the spring and remains low during the summer [11, 16, 5, 9]. The seasonal variation in the frequency of light flecks and spots show a pattern that can be related to the variation in the lice population during the year. The frequency of light flecks and spots was high in late winter and early spring, and the frequency decreased slowly during the spring, summer and autumn. Thus, these observations indicate a relative long healing period, but perhaps not as long as suggested by .
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