Correlations between production and economic variables in dairy cows on a tropical pasture

ABSTRACT. The objective of this study was to evaluate correlations between production and economic variables of lactating cows on a tropical pasture. The experiment involved ten – Holstein × ¼ Dairy Gyr cows in the middle third of lactation at an average age of 70 ± 4.6 months and an average body weight of 400 ± 55.2 kg. Cows were supplemented with a concentrate feed with different supplement compositions aiming to promote alterations in the animal performance and economic responses. Data were analyzed statistically by Pearson correlations at the 0.95 probability level. No correlations were observed for fat and total solids with economic variables (p > 0.05). Milk yield was positively correlated with (p < 0.05), but had no correlation with FC or MRR (p > 0.05). There were no correlations for milk yield with RC, FC, or MRR (p > 0.05). Positive correlations were observed for fat corrected milk yield with GRSM and RMSC (p < 0.05). Fat production (kg day‒1) was positively correlated with GRSM and RMSC (p < 0.05). The gross revenue from the sale of milk and the revenue minus feed costs showed to be highly associated with production variables.

摘要。本研究旨在评估热带牧场泌乳奶牛生产性能变量与经济变量间的相关性。试验选取10头荷斯坦与1/4奶用吉尔牛（Holstein × ¼ Dairy Gyr）的杂交泌乳牛，处于泌乳中期，平均年龄为70±4.6月龄，平均体重为400±55.2 kg。试验牛饲喂不同配方的精补料，以期调控奶牛生产性能与经济响应结果。采用Pearson相关分析法对数据进行统计学分析，显著性水平设定为0.05。乳脂与总乳固体与经济变量间未发现显著相关性（p>0.05）。产奶量与（p<0.05）呈正相关，但与FC或MRR无显著相关性（p>0.05）。产奶量与RC、FC或MRR均无显著相关性（p>0.05）。乳脂校正奶产量与GRSM及RMSC呈显著正相关（p<0.05）。乳脂产量（kg·d⁻¹）与GRSM及RMSC呈显著正相关（p<0.05）。牛乳销售收入与收益减去饲料成本后的净额，均与生产性能变量呈高度相关。