1- Agriculture and Natural Resources Research Center of Markazi Province, Arak, Iran
2- Agriculture and Natural Resources Research Center of Markazi Province, Agricultural Research, Education and Extension Organization (AREEO), Arak, Iran.
Abstract: (1720 Views)
Extended Abstract
Background: Markazi Province is recognized as one of the important centers for calf fattening in the country. This province is home to over 4.4% of Iran's total cattle and calf population, with 370,000 head of cows and calves, including purebred, hybrid, and native breeds. It ranks twelfth among the provinces in the country. Additionally, with the production of 15,000 tons of beef and veal, it accounts for approximately 3.3% of the national beef and veal output. In recent years, there has been significant interest from livestock breeders in the province for fattening Simmental calves, due to their calm temperament, better meat production efficiency, and adaptability to the province's weather conditions. This interest has prompted the province's livestock improvement deputy to implement a project aimed at scientifically assessing the productivity and fattening characteristics of this breed. Since no research has been conducted in the province to compare the growth and feedlot performance of crossbred Holstein and Simmental calves, and there is limited information about carcass characteristics and suitable slaughter weights of cattle breeds in the region, calf breeders lack detailed knowledge about the productivity, feed consumption, growth traits, and carcass quality of different breeds. Therefore, this study was conducted to compare the fattening and carcass characteristics of male Simmental and Holstein crossbred calves in a fattening unit in Markazi Province that had the necessary conditions and facilities for the project (including a scale and adequate space).
Methods: Sixty male calves with an average weight of 150 to 200 kg were divided into two groups (treatments). One group consisted of 30 Holstein crossbred calves, and the other group included 30 Simmental crossbred calves, ensuring minimal differences in weight and body condition between the two groups. Balanced and optimal diets were formulated for each group based on the nutritional needs of the calves (according to their weight) and the available nutrients in the unit, following the nutritional requirements outlined in the NRC tables for beef cattle (2016). Balanced diets were provided based on Total Mixed Ration after a 14-day feeding adaptation period. The average consumption of fodder and concentrate was adjusted to a ratio of 40 to 60 throughout the entire period. Daily feed was provided to the calves three times a day, according to their appetite. Daily feed intake was recorded. Calves were weighed monthly after a 12-hour food deprivation and before morning feeding, and the feed conversion ratios for the animals in each group were calculated. The fattening period continued until the calves reached the desired weight. At the end of the fattening period, five calves from each group were weighed and slaughtered after 12 hours of food deprivation, and their carcass weight, yield, and fat thickness at the 12th rib were measured. Comparisons between the two groups of calves in different weight categories were performed using an independent t-test with SPSS statistical software.
Results: The results indicated that the total weight gain during the fattening period was 360 kg for Simmental hybrids and 336 kg for Holstein hybrids, showing a higher weight gain (24 kg) in the Simmental group (P = 0.03). The average monthly and daily weight gains for Simmental and Holstein hybrid calves during the breeding period were 40 kg and 37.30 kg per month, and 1.33 kg and 1.24 kg per day, respectively (P = 0.032). The average daily dry matter intake during the fattening period for Simmental and Holstein hybrid calves was 8.05 kg and 8.28 kg, respectively, although this difference was not significant. The mean feed conversion ratio for the entire fattening period was 6.05 for Simmental and 6.67 for Holstein, indicating a significant difference between the two treatments (P = 0.04). The mean carcass yield for Simmental and Holstein hybrid calves at the end of the 9-month fattening period was 55.45% and 52.27%, respectively, with a significant difference between the two treatments (P = 0.01). The thickness of dorsal fat between ribs 12 and 13 was 6.05 mm for Simmental and 6.75 mm for Holstein, while the thickness of the straight muscle in the same rib range was 53.62 mm for Simmental and 51.4 mm for Holstein (P = 0.035).
Conclusion: The results demonstrated that Simmental hybrid calves exhibit better efficiency in terms of growth, feed yield, and carcass and meat characteristics compared to Holstein hybrid calves. Therefore, for the economic production of meat and the domestic supply of red meat, it is recommended that some feedlot farms in the country consider breeding this high-yielding breed, if feasible.
Type of Study:
Research |
Subject:
تغذیه نشخوارکنندگان Received: 2023/06/12 | Accepted: 2023/12/3