RESUMEN
Culled dairy cows represent a considerable source of meat production, but their carcasses may vary greatly in quality because of the wide variation in the age, stage of lactation, breed, body condition, and other characteristics of the cows at slaughter. However, the effect of crossbreeding on the value of culled cows has so far received little investigation. The aim of this observational study was to compare a range of carcass attributes of cull cows from 3-breed rotational crossbreeding using Viking Red, Montbéliarde (MO), and Holstein (HO) bulls with those of HO purebred cows. Data on 1,814 dairy cows were collected. Cows were reared together in one herd and slaughtered in 4 slaughterhouses. The carcass weight, fleshiness, and fatness scores, the total value, and the price (/kg) of each cow carcass were recorded. The culling of a few cows in the sample (n = 86) was classified by the farm manager as "urgent" following a diagnosis of injury or sickness, and this information was recorded. Carcass traits were analyzed with a mixed model which included the fixed effects of parity, days in milk, genetic group (purebred HO, 787 cows, and crossbred cows, classified according to the breed of sire within crossbreds, with 309, 428, and 290 cows sired by Viking Red, MO, and HO bulls, respectively), and interactions, and the random effects of month × year of the date of slaughter, and slaughterhouse. Logistic regression was used to investigate the association of parity, days in milk and purebred or crossbred origin with unplanned, "urgent" culling compared with regular culling. Average carcass weight across genetic groups was 297 ± 65 kg, average price 2.03 ± 0.53/kg, and average value 631 ± 269. Compared with HO, crossbred carcasses were 7 to 12% heavier depending on the breed of sire, were graded + 0.12 to + 0.28 units higher for fleshiness and + 0.26 to + 0.30 units higher for fatness, and fetched an 8 to 11% higher price. As a consequence, compared with purebred HO, carcasses from crossbreds had 15 to 24% higher value (84 to 133 more per cow), with crossbred cows sired by MO showing the greatest values. Moreover, compared with the HO cows, the crossbred cows had a 37% lower risk of being urgently removed from the herd, which raises welfare concerns and may reduce the salvage value of cull cows. Because cull cows represent a supplemental source of income for dairy farmers, the greater overall value of crossbred cull cows should be taken into account in evaluating the economic effectiveness of crossbreeding schemes.
Asunto(s)
Lactancia , Leche , Embarazo , Femenino , Bovinos , Animales , Masculino , Lactancia/genética , Paridad , Fenotipo , Hibridación GenéticaRESUMEN
OBJECTIVE: In this study, the disparity between the lengths of the lateral and medial digit in cows with a Rusterholz sole ulcer compared to non-affected cows was investigated. MATERIAL AND METHODS: In total, 100 hind feet were collected from slaughtered cows. Twenty-five feet had a pre-ulcerative lesion at the typical site, 26 had an ulcer < 1 cm² and 24 had an ulcer > 1.5 cm². Twenty-five normal feet were used as controls. The lengths of the metatarsal condyles and phalanges (Ph) were measured on plantarodorsal radiographs and three different overall lengths of the digits were generated. The software program SPSS was used for analysis. RESULTS: The mean lengths of Ph1 and Ph2 and the three mean overall lengths of the lateral digit were greater than those of the medial digit while the length of Ph3 was longer on the medial digit. With one exception, the comparison of overall length 2 of the pre-ulcerative lesion with the control group, the within-feet differences of the ulcer groups were not significantly different from the difference of the controls. CONCLUSION AND CLINICAL RELEVANCE: These results corroborate the length asymmetry of the bovine digits but further studies are needed to evaluate the effect of the asymmetry of the digits on the development of sole ulcers.