Submitted to: Journal Dairy Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: February 26, 2011
Publication Date: July 11, 2011
Citation: Broderick, G.A., Kerkman, T.M., Sullivan, H.M., Dowd, M.K., Funk, P.A. 2011. Replacing soybean meal with Upland cottonseed, Pima cottonseed, or extruded Pima cottonseed cake on production of lactating dairy cows. Journal of Dairy Science. 94(E-Supplement 1):638. Technical Abstract: Cottonseed is an important dietary ingredient for dairy cows and is fed principally as upland cottonseed. However, Pima cotton production is growing in the U.S. Pima cottonseed contains greater levels of protein, oil and gossypol, a potentially toxic compound. Heating cottonseed promotes the gossypol reaction with protein and may reduce absorption. Forty lactating Holstein cows were blocked by DIM into 5 squares and randomly assigned to treatment sequences in an incomplete 8x8 Latin square. Diets were formulated to contain (DM basis) 30% alfalfa silage, 30% corn silage, 21 to 25% high-moisture corn, and 16% CP and fed as TMR for ad libitum intake. Supplemental protein was provided from: 1) solvent-extracted soybean meal (SSBM) or SSBM plus equal CP from: 2) upland cottonseed (UCS), 3) cracked Pima cottonseed (PCS), 4) extruded Pima cottonseed cake (PCSC; prepared with an experimental heating process that removed about half the oil), 5) UCS plus PCS, 6) UCS plus PCSC, or expeller soybean meal (ESBM) plus equal CP from: 7) PCS, or 8) PCSC. Periods were 4 weeks long (total: 16 weeks). The first 2 weeks were for diet adaptation; data were collected over the last 2 weeks of each period. Blood plasma was collected on day 28 of each period. Data were analyzed using Proc Mixed in SAS. Diet affected DM intake (P < 0.05), with greatest intake on diet 6 (SSBM, CCS plus PCSC) and lowest intake on diet 3 (SSBM plus PCS). Concentration of MUN (P = 0.05) also was influenced by diet and was lowest on diets 3 (SSBM plus PCS) and 7 (ESBM plus PCS). No other production trait was affected by diet. Milk fat ranged from 3.78 to 4.25%, suggesting that there were no adverse effects from cottonseed oil. Effect of protein source on total plasma gossypol was highly significant (P < 0.001). As expected, gossypol was lowest on diet 1. Plasma gossypol was higher on PCS and lower on PCSC, than on corresponding diets containing UCS, indicating that extrusion reduced gossypol absorption. Animal performance on all diets supplemented with cottonseed products was comparable to that on SSBM.