Replacing human-edible feed ingredients with by-products increases net food production efficiency in dairy cows.

Global demand for food is increasing, and use of large amounts of potentially human-edible feedstuffs for dairy cows is an important concern. The present study examined whether feeding a by-product-based concentrate combined with high-quality grass silage to high-producing dairy cows affected feed intake and milk production compared with a conventional diet, as well as the effect on efficiency of human food production. In a changeover experiment with four 21-d periods, 24 dairy cows in mid-lactation were offered 9.6 kg of dry matter per day with 1 of 4 concentrates and high-quality grass silage ad libitum. The control concentrate was based on cereal grain (wheat, oat, and barley) and soybean meal, whereas the 3 by-product-based concentrates contained sugar beet pulp in combination with mainly heat-treated rapeseed meal, distillers grain, or a mixture of both. All diets were formulated to be isoenergetic and isonitrogenous. The cows had 10-fold higher starch intake when fed the control diet than when fed the by-product-based concentrates. Silage intake (13 kg of dry matter/d) and milk production (33 kg of energy-corrected milk/d) were not affected by the change in diet. Therefore, replacing cereals and soybean meal with human-inedible by-products in a high-quality forage diet to dairy cows increased net food protein production substantially without lowering milk production.

Faecal excretion of total and acid extractable phosphorus in dairy cows fed rations with different levels of phosphorus.

BACKGROUND: The phosphorus (P) originating from livestock operations causes eutrophication. Determination of acid extractable P (AEP) in cattle faeces has been proposed as a tool to identify excessive P feeding. The method has not yet been evaluated in controlled studies with cows subjected to individual recording of P intake. Thus the present study focused on investigating the relationship between different P fractions in faeces from cows fed rations with varying P content. The study also investigated whether AEP in faeces could be used to estimate dietary P intake in relation to the P requirement. RESULTS: The results showed that acid extractable P predicted P overfeeding. P fed in excess of requirements was largely excreted as acid extractable P. The unavailable and/or inevitably lost P fractions in the diets were smaller than assumed. CONCLUSION: This study demonstrates in experimental studies a positive relationship between measured AEP and indirectly calculated regulated P. Any P fed in excess of requirements was largely excreted as AEP. This fraction is thought to be the most mobile P fraction with regard to potential runoff losses. However, the unavailable and/or inevitably lost P fractions in the diets were smaller than assumed.

Short communication: Use of a mixture of sodium nitrite, sodium benzoate, and potassium sorbate in aerobically challenged silages.

Aerobic instability is still a common problem with many types of silages, particularly well-fermented silages. This study evaluated the effect of adding an additive mixture based on sodium nitrite, sodium benzoate, and potassium sorbate to a variety of crop materials on fermentation quality and aerobic stability of silages. Ensiling conditions were challenged by using a low packing density (104±4.3kg of dry matter/m(3)) of forage and allowing air ingression into silos (at 14 and 7 d before the end of the storage, for 8 h per event). Additive-treated silages were found to have significantly lower pH and reduced formation of ammonia-N, 2.3-butanediol, and ethanol compared with untreated control silages. Yeast growth was significantly reduced by additive treatment in comparison with untreated control silage. Consequently, additive-treated silages were considerably more aerobically stable (6.7 d) than untreated control silages (0.5 d). Overall, adding 5mL/kg of fresh crop of the additive based on sodium nitrite, sodium benzoate, and potassium sorbate reduced undesirable microorganisms in silages and thereby provided suitable ensiling conditions and prolonged aerobic stability, even under air-challenged laboratory ensiling conditions.

Feeding Moringa oleifera fresh or ensiled to dairy cows--effects on milk yield and milk flavor.

Moringa oleifera, either fresh or ensiled, was compared with Elephant grass as a main feedstuff for dairy cows. To test the effects feed had on milk yield, milk composition, ration digestibility, and the organoleptic characteristics of milk, six lactating dairy cows were used in a Changeover 3 × 3 Latin Square experiment, replicated twice. With equal intake of metabolizable energy the intake of protein and fiber differed (p < 0.001) between all diets where fresh Moringa had the highest and the Elephant grass diet had the lowest intake. Compared with the control diet, ensiled Moringa had higher digestibility (P < 0.05) of both protein and fiber. With the exception of DM digestibility, no digestibility differences were found between fresh Moringa and Moringa silage treatments. Milk yield did not differ between any of the treatments and averaged 13.7 kg cow day(-1). Milk composition was similar among all treatments. Milk from the fresh Moringa treatment, however, had a grassy flavor and aroma, significantly different from the other two treatments, even though it was normal in color and appearance. No organoleptic differences were found between milk from the control treatment and the Moringa silage treatment. The conclusion is that Moringa silage can be fed to dairy cows in large quantities to produce the same quantity and quality of milk as traditional diets.