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Abstract. We expand a previous result of Dean [Dea99] to provide a second preimage attack on all n-bit iterated hash functions with Damgård-Merkle strengthening and n-bit intermediate states, allowing a second preimage to be found for a 2 k -message-block message with about k × 2 n/2+1 +2 n−k+1 work. Using RIPEMD-160 as an example, our attack can find a second preimage for a 2 60 byte message in about 2 106 work, rather than the previously expected 2 160 work. We also provide slightly cheaper ways to find multicollisions than the method of Joux [Jou04]. Both of these results are based on expandable messages-patterns for producing messages of varying length, which all collide on the intermediate hash result immediately after processing the message. We provide an algorithm for finding expandable messages for any n-bit hash function built using the Damgård-Merkle construction, which requires only a small multiple of the work done to find a single collision in the hash function.

Sixty calves were assigned to a comparative slaughter study to determine the changes in composition of milk replacer-fed Holstein bull calves from birth to 105-kg body weight (BW). Six calves were slaughtered on day of birth and served as a baseline for comparison of compositional changes. Fifty-four calves were assigned to one of three treatments (18 calves per treatment). Calves were fed milk replacer containing 30% crude protein (CP) and 20% fat. Target growth rates for treatments 1, 2, and 3 were 500, 950, and 1400 g/d, respectively. Six calves from each treatment were slaughtered and analyzed for energy, nitrogen, ether extract, and ash when they reached 65, 85 and 105 kg of BW. Actual daily gains from birth to slaughter were 560, 973, and 1100 g, and net deposition of CP and fat were 140 and 44, 204 and 154, and 247 and 161 g/d for treatments 1, 2, and 3, respectively. Results were used to develop equations to predict retained energy [retained energy = (empty BW(0.223)) x (empty BW gain(1.32))], and retained protein, [retained protein = (184 x empty BW gain (kilograms/d)) + (17.2 x (retained energy)/empty BW gain] where retained energy is in Mcal/d, retained protein is in g/d, and empty BW and gain are in kilograms. The composition of gain observed was compared to predictions from the 1989 Dairy NRC and 1996 Beef NRC equations and demonstrated the equations do not represent the composition of gain in calves of this weight.