Document Type : Research Paper
Authors
1 1. Associate Professor, Department of Animal Nutrition and Physiology, Animal Science Research Institute of Iran, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.
2 Graduate student of Animal Science Department, Faculty of Agriculture, University of Tarbiat Modares, Tehran, Iran.
3 . Professor, Department of Animal Nutrition and Physiology, Animal Science Research Institute of Iran, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.
4 Associate Professor, Department of Animal Nutrition and Physiology, Animal Science Research Institute of Iran, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
5 Assistant Professor of Agricultural Research and Training Center and Natural Resources of Qazvin Province, Agricultural Research, Education and Extension Organization,, (AREEO), Qazvin, Iran.
Abstract
Objective: It is very important to choose an optimal and principled method for producing silage from high-moisture food materials such as fodder beet for use in animal nutrition. This study was conducted with the aim of qualitative assessment the preparation of fodder beet silage as total mixed and partial mixed ration and investigating their effect in the diet of fattening calves.
Methods: Fodder beet cultivation and harvesting were carried out at the appropriate time (the root bulking stage – prior to the initiation of reproductive growth or seed production), and after initial sampling and determination of the chemical composition of the forage, total mixed and partial mixed ration silages were produced depending on the nutritional needs of fattening calves (Holstein and Holstein- Montbéliard crossbreeds). Twenty fattening male calves with an average weight of 287±25 kg were randomly and equally divided into two groups, each fed one of the experimental treatments containing total mixed and partial mixed ration silages. This study was conducted over a period of 110 days (90 days’ main period), during which the animals were weighed and samples of feed, feed residue, and feces were taken at 30-day intervals after adaptation period to assess daily weight gain, feed consumption, and digestibility.
Results: The visual and qualitative evaluation of silages showed that the preparation of fodder beet silage as a partial mixed ration had a lower pH and fleig point compared to total mixed ration, however, no difference was observed between the two treatments in terms of color, odor, and texture of silage. Changes in crude protein and ammonia nitrogen content indicated better conditions in the partial mixed ration silage (P<0.05). The intake of dry matter and crude protein was higher in partial mixed ration silage compared to total mixed ration(P<0.05). Nutrient digestibility in calves fed the partial mixed ration was superior and showed a significant difference compared to total mixed ration (P<0.05). The average initial and final weights of calves were not affected by the two treatments. Although the average daily weight gain was higher in the partial mixed ration (P<0.05), due to the higher dry matter intake, the feed conversion ratio was not statistically significant in the two treatments. Economic analysis of diets and performance of the fattening male calves showed that the income and profit from rearing male calves fed with fodder beet silage as a partial mixed ration were higher compared to total mixed ration (P<0.05).
Conclusions: The evaluation of the qualitative and visual conditions of silage showed that although both methods of preparing silage as total mixed and partial mixed ration achieved acceptable conditions and can be used to preserve high-moisture forages in livestock farming, but the qualitative performance of silage production was better in partial mixed ration mode. The intake and digestibility of nutrients in lambs fed with partial mixed ration were better compared to total mixed ration silage, and considering the greater daily weight gain of fattening male calves in this group and the greater profit achieved in this treatment, it seems that depending on the breeding conditions and if labor is available, partial mixed ration silage can be used compared to feeding livestock with total mixed ration silage. Overall, due to the limited existing research, further complementary studies are recommended to confirm these findings and to assess their effects on different livestock species.
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