The vaccine against gonadotropin releasing factor (GnRF), Improvac®, has recently emerged as an option for rearing market gilts up to heavier harvest weights. Improvac's® temporary suppression of the ovarian function and gonadal hormones results in greater feed intake and better welfare from avoidance of sexual behavioral problems. Based on 22 published articles, our meta-analysis has quantified the effect of immunizing gilts against GnRF on parameters relevant for pig producers, pork packers and retailers/consumers. The meta-analyses included growth performance and final harvest parameters, general carcass traits and yield of valuable meat, meat and fat quality parameters. Primary analyses considered studies without ractopamine, subgroup and additional analyses assessed the impact of co-variates. From the perspective of pig producers, primary analyses showed that immunized (IM) gilts have significantly (P < 0.001) increased average daily gain (+45.1 g/day) and daily feed intake (+0.19 kg/day), higher final live weight (+4.0 kg) and more backfat (+2.8 mm). From the perspective of the pork packers, IM gilts have heavier carcasses (+3.2 kg; P < 0.001), whereas dressing percentage is similar. IM gilts are less lean (-1.5% units; P < 0.001) and have 0.21% units more intramuscular fat (P = 0.001). The yield of ham, shoulder, and loin is similar, whereas the yield of belly is significantly higher (+0.28 kg; P < 0.001). There are no differences in meat quality parameters (color, pH24, and drip loss) between IM gilts and untreated gilts, whereas a lower iodine value in IM gilts indicates an improved fat quality. Further subgroup and additional analyses confirmed the validity of our meta-analysis.

中文翻译：

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针对市场后备母猪的促性腺激素释放因子的免疫效果：与养猪生产者，猪肉包装者和零售商/消费者有关的参数的荟萃分析。

抗促性腺激素释放因子（GnRF）的疫苗Improvac®最近作为一种选择来饲养市集母猪，以达到更高的收获重量。Improvac's®暂时抑制卵巢功能和性腺激素可避免发生性行为问题，从而增加采食量并改善福利。根据发表的22篇文章，我们的荟萃分析已量化了针对GnRF免疫后备母猪在与猪生产者，猪肉包装者和零售商/消费者有关的参数上的效果。荟萃分析包括生长性能和最终收获参数，一般general体性状和有价值的肉，肉和脂肪质量参数的产量。初步分析考虑了没有莱克多巴胺，亚组的研究，其他分析评估了协变量的影响。从养猪者的角度来看，初步分析表明，免疫（IM）的后备母猪的平均日增重（+45.1 g /天）和日均采食量（+0.19 kg /天）显着（P <0.001）增加，最终活重（+4.0 kg）和更多后脂肪（+2.8毫米）。从猪肉包装工的角度来看，IM后备母猪的cas体重量较重（+3.2 kg； P <0.001），而选矿率却相似。IM后备母猪的瘦肉较少（-1.5％单位； P <0.001），而肌内脂肪多0.21％单位（P = 0.001）。火腿，肩膀和里脊肉的产量相似，而腹部的产量明显更高（+0.28 kg； P <0.001）。IM后备母猪和未经处理的后备母猪的肉品质参数（颜色，pH24和滴落损失）没有差异，而IM后备母猪的碘值较低表明脂肪品质得到改善。