Department of Animal and Food Sciences, University of Kentucky, Lexington 40546, USA.
J Dairy Sci. 2013 Jun;96(6):4041-6. doi: 10.3168/jds.2012-6069. Epub 2013 Apr 12.
The objective of this study was to examine changes in teat-end hyperkeratosis (HK) in a herd transitioning from a standard pulsation milking system to an individual quarter pulsation milking system. The Milpro P4C (Milkline, Gariga di Podenzano, Italy) system stops milking individual quarters using an individual quarter pulsation milking system with 4 independent pulsation channels per cluster instead of 2. Teat-end HK was evaluated immediately after cluster removal using a scoring system where N signifies no ring; S signifies a smooth, raised ring; R signifies a rough ring; and VR signifies a very rough ring. Scorings were classified for 69 cows (48 Holstein, 12 crossbred, and 9 Jersey) on 5 dates relative to installation of the Milpro P4C system on April 28, 2011, as follows: April 7 (PRE1); April 21 (PRE2), May 12 (POST1), May 26 (POST2), and June 9 (POST3). Hyperkeratosis classifications were converted to numerical scores as follows: N=1, S=2, R=3, and VR=4. The MIXED procedure of SAS (SAS Institute Inc., Cary, NC) was used to evaluate fixed effects of age, breed, parity, teat position, and all interactions on teat-end HK score with variables repeated by scoring with cow within breed as subject. The effects of teat position and scoring × breed on teat-end HK score were significant. Holstein HK scores improved from PRE2 to POST3 (1.64 ± 0.09 and 1.42 ± 0.10, respectively), POST1 to POST3 (1.59 ± 0.10 and 1.41 ± 0.10, respectively), and POST2 to POST3 (1.53 ± 0.10 and 1.42 ± 0.10, respectively). Crossbred HK scores did not differ among scorings. Jersey HK scores worsened from POST1 to POST3 (1.32±0.21 and 1.63 ± 0.22, respectively). For all cows included in the final analysis, right front and left front HK scores were higher than right rear and left rear HK scores (1.58 ± 0.09, 1.62 ± 0.09, 1.37 ± 0.09, and 1.36 ± 0.09, respectively). However, a significant decrease in teat-end HK scores for Holsteins did occur from PRE1 to PRE2 (1.75 ± 0.10 and 1.63 ± 0.10, respectively) and may represent biological variation in teat-end HK over time unrelated to installation of the individual quarter pulsation system. Individual quarter pulsation milking systems may prevent overmilking and reduce HK in Holstein cows. Further research is warranted to understand the breed differences observed in this study.
本研究的目的是检验从标准脉动挤奶系统过渡到个体分群脉动挤奶系统时，乳区末端过度角化（HK）的变化情况。Milpro P4C（Milkline，Gariga di Podenzano，意大利）系统使用个体分群脉动挤奶系统停止挤奶，每个分群有 4 个独立的脉动通道，而不是 2 个。在 2011 年 4 月 28 日安装 Milpro P4C 系统后，立即使用评分系统在移除乳区时评估乳区末端 HK，其中 N 表示无环；S 表示光滑、隆起的环；R 表示粗糙的环；VR 表示非常粗糙的环。对 69 头奶牛（48 头荷斯坦牛、12 头杂交牛和 9 头泽西牛）在以下 5 个日期进行评分：4 月 7 日（PRE1）；4 月 21 日（PRE2）；5 月 12 日（POST1）；5 月 26 日（POST2）和 6 月 9 日（POST3）。将角化分级转换为数值评分如下：N=1、S=2、R=3、VR=4。使用 SAS（SAS Institute Inc.，Cary，NC）的 MIXED 过程评估年龄、品种、胎次、乳区位置和所有交互作用对乳区末端 HK 评分的固定影响，变量重复，以品种内的奶牛为主体进行评分。乳区位置和评分×品种对乳区末端 HK 评分的影响显著。荷斯坦牛的 HK 评分从 PRE2 到 POST3 有所改善（分别为 1.64±0.09 和 1.42±0.10），从 POST1 到 POST3 有所改善（分别为 1.59±0.10 和 1.41±0.10），从 POST2 到 POST3 有所改善（分别为 1.53±0.10 和 1.42±0.10）。杂交牛的评分在各次评分之间没有差异。泽西牛的 HK 评分从 POST1 到 POST3 恶化（分别为 1.32±0.21 和 1.63±0.22）。对于最终分析中包括的所有奶牛，右前和左前 HK 评分高于右后和左后 HK 评分（分别为 1.58±0.09、1.62±0.09、1.37±0.09 和 1.36±0.09）。然而，荷斯坦牛从 PRE1 到 PRE2 的乳区末端 HK 评分确实显著下降（分别为 1.75±0.10 和 1.63±0.10），这可能代表了与个体分群脉动系统安装无关的乳区末端 HK 随时间的生物学变化。个体分群脉动挤奶系统可能会防止过度挤奶并减少荷斯坦牛的 HK。需要进一步研究以了解本研究中观察到的品种差异。
