Influence of lactation number and parity on milk yield of Saanen goat’s breed

ABSTRACT The aim of this research was to determine the influence of lactation number and parity on milk yield of Saanen goat’s breed. It has been concluded that milk yield was higher for goats that had given birth to twins and three kids than for goats that had given birth to a single kid (P<0.05). The longevity has a great positive impact on production, given that goats in the fifth lactation produced more milk than goats in first or second lactation (P<0.05), while goats in the sixth lactation still produced more milk than goats in first lactation (P<0.05). During the period from 2014- 2019, the research was conducted on a farm of multiparous Saanen goats in Vojvodina (northern part of Serbia). In the observed period, the farm had between 350 and 400 goats per milking, and the research included a total of 1,628 concluded lactations, within which the first lactations were the most 484, then the second 381. According to the number of lactations, goats were grouped into classes from one to seven and from one to three for parity. By comparing each individual lactation, it was determined that in first lactation goats produced significantly lower milk than goats in the rest lactations(P<0.05), except the seventh. Research has shown that lactation number has a significant influence on milk yield (P=0.00). Increasing the fertility of goats significantly affects the production capacity of dairy goats, since does with a larger number of kids in the litter had a significantly higher milk production (P<0.05). Due to the larger number of kids in the litter, milk production also increases. Likewise, it is assumed that the increase in milk yield of goats with two and three kids is a consequence of a larger placenta, i.e. stronger lactogenic activity during pregnancy.摘要 本研究旨在探究泌乳次数与胎次对萨能奶山羊（Saanen goat）产奶量的影响。研究结果表明，产双羔与三羔的母羊产奶量显著高于产单羔的母羊（P<0.05）。泌乳胎次的增加对生产性能具有显著正向影响：第五泌乳期母羊产奶量显著高于第一、二胎次母羊（P<0.05），第六泌乳期母羊产奶量仍显著高于第一胎次母羊（P<0.05）。本研究于2014-2019年间在塞尔维亚北部伏伊伏丁那地区的一处经产萨能奶山羊养殖基地开展。该基地在观测期内每次挤奶作业的存栏母羊数量为350~400头，本研究共纳入1628个完整泌乳周期，其中第一泌乳周期数量最多，共计484个，第二泌乳周期次之，共381个。根据泌乳次数将母羊划分为1~7泌乳期组别，根据胎次划分为1~3胎次组别。通过对单个泌乳周期的对比分析可知，第一泌乳期母羊产奶量显著低于其余各泌乳期母羊（P<0.05），第七泌乳期除外。研究证实，泌乳次数对产奶量具有显著影响（P=0.00）。提高母羊繁殖力可显著提升奶山羊生产性能：窝产羔数更多的母羊产奶量显著更高（P<0.05）。窝产羔数越多，产奶量也随之提升。同理，研究推测产双羔与三羔母羊的产奶量提升，源于胎盘面积更大，即妊娠期间泌乳活性更强。