Astessiano A L, Carriquiry M, Mattiauda D A, Adrien M L, Chilibroste P, Meikle A
School of Agronomy, Universidad de la República, Montevideo, Uruguay.
School of Veterinary Medicine, Universidad de la República, Montevideo, Uruguay.
Reprod Domest Anim. 2017 Oct;52(5):798-805. doi: 10.1111/rda.12981. Epub 2017 Apr 12.
The study postulated that differential nutritional management during the early lactation period would be reflected in endometrial expression of genes related to embryo growth at the end of the voluntary waiting period. Thus, the effect of the combined use of total mixed ration (TMR) and grazing under different herbage allowances during the first 75 days post-partum (DPP) on endometrial gene expression was evaluated in primiparous dairy cows. Cows were blocked by body weight, age and body condition score and randomly assigned to three grazing treatments: high (HA, 30 kg DM per cow per day), medium (MA, 15 kg DM per cow per day) and low (LA, 7.5 kg DM per cow per day) herbage allowance (mixed pasture, 2,600 kg DM per ha) plus 8 kg DM of supplement or TMR (55% forage, 45% concentrate) fed ad libitum (TMR) from calving to 75 DPP. At 57 DPP, cows were synchronized for oestrus (day 0, 68 DPP) and at day 7, endometrial biopsies were obtained. The nutritional treatment did not affect insulin, IGF-1 and leptin concentrations on days 0, 4 or 7. Expression of IGF1, IGFBP3, IGFBP4, ADIPOR1 and ADIPOR2 mRNA was significantly affected by the nutritional treatment. Endometrial IGF1 and IGFBP4 mRNA were twofold greater in TMR and HA than MA and LA cows. Expression of IGFBP3 and ADIPOR1 mRNAs was greater in TMR and HA than MA cows, but did not differ from LA cows. All groups had greater expression of ADIPOR2 mRNA than MA cows. This study provided solid evidence of the importance of nutritional management during early lactation on uterine environment at the end of the voluntary waiting period. The greater expression of genes related to embryo growth and uterine function (IGF system, progesterone and adiponectin receptors) in cows fed diets maximizing energy intake suggests a favourable environment for embryonic growth, which may explain the improved reproductive performance of cows in good energy balance.
该研究推测，泌乳早期不同的营养管理方式会在自愿等待期结束时体现在与胚胎生长相关的子宫内膜基因表达上。因此，本研究评估了初产奶牛产后75天内（DPP）全混合日粮（TMR）与不同牧草采食量下放牧相结合对子宫内膜基因表达的影响。奶牛按体重、年龄和体况评分进行分组，并随机分配到三种放牧处理组：高牧草采食量组（HA，每头奶牛每天30千克干物质）、中牧草采食量组（MA，每头奶牛每天15千克干物质）和低牧草采食量组（LA，每头奶牛每天7.5千克干物质）（混合牧场，每公顷2600千克干物质），再加上从产犊到75 DPP期间随意采食的8千克干物质补充料或TMR（55%粗饲料，45%精饲料）。在57 DPP时，使奶牛同步发情（第0天，68 DPP），并在第7天采集子宫内膜活检样本。营养处理对第0、4或7天的胰岛素、IGF - 1和瘦素浓度没有影响。IGF1、IGFBP3、IGFBP4、ADIPOR1和ADIPOR2 mRNA的表达受到营养处理的显著影响。TMR组和HA组奶牛的子宫内膜IGF1和IGFBP4 mRNA比MA组和LA组奶牛高出两倍。TMR组和HA组奶牛的IGFBP3和ADIPOR1 mRNA表达高于MA组奶牛，但与LA组奶牛无差异。所有组的ADIPOR2 mRNA表达均高于MA组奶牛。本研究为泌乳早期营养管理对自愿等待期结束时子宫环境的重要性提供了确凿证据。能量摄入量最大化的日粮喂养的奶牛中，与胚胎生长和子宫功能相关的基因（IGF系统、孕酮和脂联素受体）表达更高，这表明存在有利于胚胎生长的环境，这可能解释了能量平衡良好的奶牛繁殖性能提高的原因。
