The anterior tooth development of cattle presented for slaughter: an analysis of age, sex and breed.

In a cross-sectional study, data from records of cattle slaughtered over a 1-year period at a large abattoir in South West England were analysed using an ordered category response model to investigate the inter-relationships between age, sex and breed on development of the permanent anterior (PA) teeth. Using the model, transition points at which there was a 50% probability of membership of each category of paired PA teeth were identified. Data from ∼60,000 animals were initially analysed for age and sex effect. The age transition was found to be ∼23 months moving from zero to two teeth; 30 months for two to four teeth; 37 months for four to six teeth and 42 months for six to eight teeth. Males were found to develop, on average, ∼22 days earlier than females across all stages. A reduced data set of ∼23,000 animals registered as pure-bred only was used to compare breed and type interactions and to investigate sex effects within the sub-categories. Breeds were grouped into dairy and beef-type and beef breeds split into native and continental. It was found that dairy-types moved through the transition points earlier than beef-types across all stages (interval varying between ∼8 and 12 weeks) and that collectively, native beef breeds moved through the transition points by up to 3 weeks earlier than the continental beef breeds. Interestingly, in contrast to beef animals, dairy females matured before dairy males. However, the magnitude of the difference between dairy females and males diminished at the later stages of development. Differences were found between breeds. Across the first three stages, Ayrshires and Guernseys developed between 3 and 6 weeks later than Friesian/Holsteins and Simmental, Limousin and Blonde Aquitaine 6 and 8 weeks later than Aberdeen Angus. Herefords, Charolais and South Devon developed later but by a smaller interval and Red Devon and Galloway showed the largest individual effect with transition delayed by 8 to 12 weeks.

Impact of the duration of control of cattle lice with eprinomectin on leather quality.

The relationship between lice infestation in calves during their first winter and damage to the leather produced was investigated in a trial involving 500 calves, 100 of which were treated with a pour-on endectocide during the first winter. All the calves received routine lice treatment in the second winter and were reared to slaughter weight. The hides were removed at the abattoir, tanned, inspected for lice-related damage, and graded according to their suitability for the production of high quality leather. The untreated group developed natural infestations of the chewing louse (Bovicola bovis) during the first winter but none was observed in the second winter. Hides from cattle infested with lice in their first winter had higher levels of lice damage than hides from those treated with eprinomectin, at both the chrome-tanned and dried dyed-crust stages of leather production.

Relationship between lice infestation and leather damage in cattle.

The relationship between lice infestation and leather damage was investigated in a trial involving 61 cattle, half of which were treated with ectoparasiticides for lice control either in their first or second year. Hides from the lice-free and lousy calves were removed manually at an abattoir, tanned and inspected for lice-related damage, commercially referred to as light spot and/or fleck. In both the first- and second-year animals there was a significant difference between the hides of the lousy and lice-free animals, confirming that the chewing louse Bovicola bovis is a cause of winter light spot. There was also a difference between the two groups in the levels of scratch damage. After the infested animals had been treated with fenvalerate and eprinomectin to kill all the lice, the damage to the hides had not been fully reversed 13 weeks later.

Production factors that influence the hygienic condition of finished beef cattle.

A survey was conducted at five UK abattoirs to trace the source of dirty beef cattle and identify factors in the production chain that contributed to their dirtiness. The Meat Hygiene Service Clean Livestock score categories were used and the animals' histories were traced back to their farm of origin. Comprehensive information was collected relating to the farm, transport and lairage phases for 675 cattle from 85 batches. The mean score of the animals on arrival at the abattoir was 1.57, with 2.8 per cent in categories 3 and 4, and none in category 5. Regression analysis, blocking the data by farm of origin, revealed that age, feed type, coat length, clipping, journey distance and time, and abattoir were the six principal factors that affected the scores. Cattle under 20 months of age were cleaner than older cattle. Dry diets resulted in lower scores than wet diets. 'Shorthair' cattle were cleaner than 'medium' or 'longhair' cattle, and cattle which had been clipped were cleaner than unclipped animals. The cattle which had travelled over 150 miles (15 per cent) were dirtier than the others. Within each abattoir there were variations in score between 1 and 4, and the mean scores of the five abattoirs ranged from 1.19 to 1.76. A significant part of this variation could only be accounted for by unmeasured variables such as abattoir management practice, assessors' categorisations and climate.

Effects of fleece soiling and skinning method on the microbiology of sheep carcases.

The fleece of sheep becomes soiled primarily on the abdomen and on the legs. A five-category scoring scale for soiling of the fleece was defined, with score 1 being clean and dry and score 5 being wet and heavily soiled with faecal material. Twenty sheep with each fleece score were slaughtered and dressed on a commercial 'inverted' slaughter line. Swab samples were taken from the shoulder and the abdomen of the carcases immediately after skinning, and total viable counts and the numbers of Enterobacteriaceae were determined. The condition of the fleece significantly affected the microbial load on these parts of the dressed carcase, with the carcases derived from sheep with increasingly dirty fleeces carrying up to 1000 times more microorganisms, and a higher proportion of the carcases being contaminated with Enterobacteriaceae. Modifications to the dressing procedure were made to try to reduce carcase contamination at the shoulder. The application of bulldog clips to prevent direct contact between the fleece and the underlying muscles resulted in higher counts on carcases with a fleece score of 3, probably owing to contamination from the hands of the slaughterman and the problems with ensuring that the clips were in place before contamination had occurred. Delaying the skinning of the shoulder until later in the pelt removal process achieved worthwhile reductions in the contamination of the shoulder of carcases with a fleece score of 4, although the total viable counts were still higher than carcases with a score of 3.