Short term effects of feeding calcium salts of poultry oil as fat supplement on feed intake, total-tract digestibility, chewing activity, and milk production of dairy cows

Abstract

The effects of feeding calcium salts of poultry oil as fat supplement on feed intake, nutrient digestion, feeding behavior and milk production of dairy cows were investigated. Twenty four Holstein cows (BW = 589 ± 41 kg; DIM = 105 ± 26.7 d [range of 60–147 d]; milk production = 41.1 ± 3.9 kg/d; mean ± SD) were used in a completely randomized design for 4 weeks. Three treatment diets were evaluated with measurements obtained from 8 cows per treatment. Treatments included (1) a diet supplemented with calcium salts of poultry oil (Ca-PO; Lador fat, Sepahan Aala Oil co., Isfahan, Iran); (2) a diet supplemented with a palmitic acid-enriched fat supplement (PA; Energizer RP-10, IFFCO, Johor, Malaysia); and (3) a diet supplemented with 50% Ca-PO and 50% PA (POPA). Oleic acid was the main fatty acid of Ca-PO, whereas palmitic acid was the major fatty acid of PA. The fat types were supplemented at 1.74% of dietary dry matter and the diets were fed ad libitum as TMR, twice daily. Dry matter intake (DMI) was greater for cows fed Ca-PO and POPA than cows fed PA, but dry matter digestibility tended to be greater in PA than other treatments. Chewing activity, expressed as min per day and min per kg of dry matter intake, was not affected by dietary treatments. Cows fed Ca-PO had greater milk production than cows fed PA, and cows fed POPA were intermediate (41.0, 39.7, and 38.9 kg/d for Ca-PO, POPA, and PA, respectively). Protein yield was greater for Ca-PO treatment than PA, whereas POPA was intermediate (1.22, 1.14, and 1.09 kg/d for Ca-PO, POPA, and PA, respectively). The percentage of milk protein also tended to be greater in Ca-PO than PA, whereas fat yield tended to be lower in POPA than other treatments. Production of FCM and the percentage of milk fat, however, were not affected by treatment. Feed efficiency expressed as milk production per kg DMI was greater for PA than other treatments, but feed efficiency determined by fat corrected milk production did not differ significantly among treatments. In conclusion, feeding calcium salts of poultry oil improved production by mid-lactation dairy cows but decreased feed efficiency. Keywords: Poultry oil, Dairy cows, Performance