English abstract
To utilize locally available feed resources with livestock production in hot climates, dried sardines were incorporated into diets for lactating dairy cows. Fourteen Holstein and13 Australian Milk Zebu multiparous cows were used in a 70-day continuous feeding experiment. Isonitrogenous and isoenergetic diets containing either soybean meal or dried sardines (supplied 40% of dietary crude protein) were fed ad - libitum. Comparisons between diets were made during the 7-week experimental period. The experiment was conducted as a 2 x 2 factorial arrangement of treatment, with diet and breed as main factors. Ruminal pH, ammonia N, total and individual volatile fatty acids concentrations were not altered by the feeding of dried sardines. Intakes of dry matter, energy, crude protein, and acid detergent fiber were lower (P<0.05) in both breeds of cows fed dried sardines. Intakes of ether extract and ash were higher (P<0.05) in cows fed dried sardines. Although it was not statistically significant, milk production was higher (P>0.05) in Holstein cows fed dried sardines than those fed the control diet (16.2 vs 15.1 kg/d). Feeding of dried sardines did not affect milk composition and compositional yields. Milk production was higher (P<0.01) in Holstein than Australian Milk Zebu cows. Effect of diet and breed interaction on milk production was significant (P<0.01). Potential of feeding marine proteins may be higher for higher milk producers (Holstein) than lower producers (Australian Milk Zebu). Reproduction parameters, body condition scores, and heat-stress associated parameters were not affected by the feeding of dried sardines. This study suggests that dried sardines could be incorporated into diets of lactating dairy cows without affecting milk production.
