Darfour-Oduro K A, Sottie E T, Hagan B A, Okantah S A
CSIR-Animal Research Institute, PO Box AH 20, Achimota, Ghana.
Trop Anim Health Prod. 2010 Mar;42(3):349-56. doi: 10.1007/s11250-009-9425-5. Epub 2009 Aug 23.
Milk yield traits and lactation length of two breeds of cattle raised on natural pasture with little or no supplementation were assessed. A total of 42 573 daily milk records on 98 Friesian-Sanga cows collected over a period of 10 years and 17 790 daily milk records on 72 Sanga cows spanning a 6-year period were used in the study. Traits examined for each breed were daily milk yield, total milk yield, 305-day milk yield, 305-day milk yield/day and lactation length. Friesian-Sanga cows outperformed their Sanga counterparts in all traits studied. Friesian-Sanga cows had an average daily milk yield of 1.35 +/- 0.00 kg; average total milk yield of 266 +/- 12 kg; average 305-day milk yield of 339 +/- 10 kg; average 305-day milk yield/ day of 1.11 +/- 0.03 kg and mean lactation length of 201.1 +/- 6.9 days. Average values for Sanga cows were 1.01 +/- 0.00 kg as daily milk yield; 162 +/- 12 kg as total milk yield; 244 +/- 10 kg as 305-day milk yield; 0.80 +/- 0.03 kg as 305-day milk yield/day. Mean lactation length for Sanga cows was 164.1 +/- 9.4 days. Season of calving significantly (P < 0.05) influenced daily milk yield of Friesian-Sanga cows and all traits of Sanga cows with animals calving in the major rainy season surpassing those that calved in the minor and dry seasons. Daily milk yield for both Friesian-Sanga and Sanga cows was significantly (P < 0.05) influenced by season of lactation. Daily milk yield gradually declined from second parity towards the sixth parity for Friesian-Sanga cows. A gradual increase in daily milk yield from first to third parity was observed in Sanga cows. Year of calving significantly influenced all traits for both breeds. Genetic improvement in milk yield traits and lactation length is achievable for both breeds of cattle as co-efficient of variation of traits were moderate to high.
对在几乎没有或没有补充饲料的天然牧场上饲养的两个品种牛的产奶量性状和泌乳期进行了评估。本研究使用了在10年期间收集的98头黑白花-桑加牛的42573条日产奶记录，以及在6年期间收集的72头桑加牛的17790条日产奶记录。对每个品种检测的性状包括日产奶量、总产奶量、305天产奶量、305天日均产奶量和泌乳期。在所有研究的性状方面，黑白花-桑加牛的表现优于其桑加牛 counterparts。黑白花-桑加牛的平均日产奶量为1.35±0.00千克；平均总产奶量为266±12千克；平均305天产奶量为339±10千克；平均305天日均产奶量为1.11±0.03千克，平均泌乳期为201.1±6.9天。桑加牛的日产奶量平均值为1.01±0.00千克；总产奶量为162±12千克；305天产奶量为244±10千克；305天日均产奶量为0.80±0.03千克。桑加牛的平均泌乳期为164.1±9.4天。产犊季节对黑白花-桑加牛的日产奶量和桑加牛的所有性状有显著影响（P<0.05），在主要雨季产犊的动物超过在次要雨季和旱季产犊的动物。黑白花-桑加牛和桑加牛的日产奶量均受泌乳季节的显著影响（P<0.05）。黑白花-桑加牛的日产奶量从第二个胎次到第六个胎次逐渐下降。桑加牛从第一个胎次到第三个胎次日产奶量逐渐增加。产犊年份对两个品种的所有性状均有显著影响。由于性状的变异系数为中到高，两个品种牛的产奶量性状和泌乳期的遗传改良是可以实现的。
