Harvey Kelsey M, Cooke Reinaldo F, Colombo Eduardo A, Rett Bruna, de Sousa Osvaldo A, Harvey Lorin M, Russell Jason R, Pohler Ky G, Brandão Alice P
Department of Animal Science, Texas A&M University, College Station, TX 77845, USA.
Prairie Research Unit, Mississippi State University, Prairie, MS 39756, USA.
J Anim Sci. 2021 May 1;99(5). doi: 10.1093/jas/skab095.
One hundred and ninety non-lactating, pregnant beef cows (three-fourth Bos taurus and one-fourth Bos indicus; 138 multiparous and 52 primiparous) were assigned to this experiment at 117 ± 2.2 d of gestation (day 0). Cows were ranked by parity, pregnancy type (artificial insemination = 102 and natural service = 88), body weight (BW), and body condition score (BCS) and assigned to receive a supplement containing: 1) sulfate sources of Cu, Co, Mn, and Zn (INR; n = 95) or 2) an organic-complexed source of Cu, Mn, Co, and Zn (AAC; Availa 4; Zinpro Corporation, Eden Prairie, MN; n = 95). The INR and AAC provided the same daily amount of Cu, Co, Mn, and Zn, based on 7 g of the AAC source. From day 0 to calving, cows were maintained in a single pasture and were segregated three times weekly into 1 of the 24 individual feeding pens to receive treatments. Cow BW and BCS were recorded on days -30, 97, upon calving, and at weaning (day 367). Milk production was estimated at 42 ± 0.5 d postpartum via weigh-suckle-weigh (WSW) method. Liver biopsies were performed in 30 cows per treatment on days -30, 97, upon calving, and the day after WSW. Calf BW was recorded at birth and weaning. Liver and longissimus muscle (LM) biopsies were performed in 30 calves per treatment upon calving and 24 h later, the day after WSW, and at weaning. No treatment effects were detected (P ≥ 0.49) for cow BCS during gestation, despite AAC cows having greater (P = 0.04) BW on day 97. Liver Co concentrations were greater (P < 0.01) for AAC compared with INR cows, and liver concentrations of Cu were greater (P = 0.02) for INR compared with AAC cows on day 97. Upon calving, INR cows had greater (P ≤ 0.01) liver Cu and Zn concentrations compared with AAC cows. No other treatment differences were noted (P ≥ 0.17) for cow and calf liver trace mineral concentrations. Cows receiving AAC had greater (P = 0.04) hepatic mRNA expression of metallothionein 1A at calving, and their calves had greater (P = 0.04) hepatic mRNA expression of superoxide dismutase at weaning. Milk production did not differ between AAC and INR cows (P = 0.70). No treatment effects were detected (P ≥ 0.29) for mRNA expression of LM genes associated with adipogenic or muscle development activities in calves at birth and weaning. Calf birth and weaning BW also did not differ (P ≥ 0.19) between treatments. In summary, supplementing AAC or INR to beef cows during the last 5 mo of gestation yielded similar cow-calf productive responses until weaning.
190头非泌乳期怀孕肉牛（四分之三为黄牛，四分之一为瘤牛；138头经产牛和52头初产牛）在妊娠117±2.2天（第0天）时被分配到本试验中。根据胎次、妊娠类型（人工授精=102头，自然交配=88头）、体重（BW）和体况评分（BCS）对母牛进行排名，并分配接受含有以下成分的补充剂：1）铜、钴、锰和锌的硫酸盐来源（INR；n=95）或2）铜、锰、钴和锌的有机络合来源（AAC；Availa 4；Zinpro公司，明尼苏达州伊甸草原；n=95）。基于7克AAC来源，INR和AAC提供相同每日量的铜、钴、锰和锌。从第0天到产犊，母牛饲养在单一牧场，每周分三次被分到24个单独的饲养栏中的1个接受处理。在第-30天、97天、产犊时和断奶时（第367天）记录母牛的BW和BCS。产后42±0.5天通过称重-哺乳-称重（WSW）方法估计产奶量。在第-30天、97天、产犊时和WSW后一天，对每种处理的30头母牛进行肝脏活检。在出生和断奶时记录犊牛的BW。在产犊时、WSW后一天和断奶时，对每种处理的30头犊牛进行肝脏和背最长肌（LM）活检。尽管在第97天AAC组母牛的BW更高（P=0.04），但在妊娠期间未检测到处理对母牛BCS的影响（P≥0.49）。与INR组母牛相比，AAC组母牛的肝脏钴浓度更高（P<0.01），在第97天，与AAC组母牛相比，INR组母牛的肝脏铜浓度更高（P=0.02）。产犊时，与AAC组母牛相比，INR组母牛的肝脏铜和锌浓度更高（P≤0.01）。在母牛和犊牛肝脏微量矿物质浓度方面未发现其他处理差异（P≥0.17）。接受AAC的母牛在产犊时金属硫蛋白1A的肝脏mRNA表达更高（P=0.04），其犊牛在断奶时超氧化物歧化酶的肝脏mRNA表达更高（P=0.04）。AAC组和INR组母牛的产奶量没有差异（P=0.70）。在出生和断奶时，未检测到处理对犊牛与脂肪生成或肌肉发育活动相关的LM基因mRNA表达的影响（P≥0.29）。处理之间犊牛出生和断奶时的BW也没有差异（P≥0.19）。总之，在妊娠最后5个月向肉牛补充AAC或INR，在断奶前产生了相似的母牛-犊牛生产反应。
