van Zyl C L, Bokkers E A M, Kemp B, Agenäs S, van Knegsel A T M
Adaptation Physiology Group, Wageningen University and Research, 6700 AH Wageningen, the Netherlands; Animal Production Systems Group, Wageningen University and Research, 6700 AH Wageningen, the Netherlands.
Animal Production Systems Group, Wageningen University and Research, 6700 AH Wageningen, the Netherlands.
J Dairy Sci. 2025 Aug 6. doi: 10.3168/jds.2025-26619.
In dairy cow-calf contact (CCC) systems, cows and calves stay together for a prolonged period, allowing for more suckling and strengthening of the maternal bond compared with the early separation of cow and calf in conventional dairy systems. Extended suckling in CCC systems is related to greater calf growth, although knowledge on consequences of extended suckling for body condition and metabolic and inflammatory variables of calves is limited. This study aimed to evaluate growth, backfat thickness, energy metabolism, and inflammatory status of calves with minimum 12 wk of CCC followed by gradual weaning and separation compared with calves separated from their dam 13.5 h after birth. In 2 experimental batches, treatment group allocation was balanced for cow parity and breed (Swedish Holstein or Swedish Red) and for calf sex and breed (dairy or beef-on-dairy crossbred). Calves were allowed full contact with dams (FC, n = 21) until the start of the 10-d fence-line weaning with gradually reduced suckling opportunities at average 12.5 wk of age. Conventionally reared calves with no contact with dams (NC, n = 22) received 8 L whole milk/d from teat buckets and were first individually housed for 1 wk followed by group housing. The NC calves were gradually weaned over 10 d when 12.2 wk old. In addition, both FC and NC calves had ad libitum access to concentrates and roughage. Preweaning growth was greater in FC than NC calves (1.4 vs. 1.1 ± 0.06 kg/d; LSM ± SEM). During the preweaning period, serum glucose, insulin, IGF-1, and haptoglobin concentration did not differ between treatment groups, but nonesterified fatty acids (NEFA) concentration was greater in FC than NC calves. After weaning, serum glucose, insulin, and NEFA concentration decreased for both FC and NC calves. Serum IGF-1 concentration decreased after weaning for FC calves but not for NC calves. Postweaning, the FC calves retained their BW advantage and higher backfat thickness compared with NC calves despite having lower postweaning growth than NC calves in batch 1 (1.1 ± 0.06 kg/d vs. 1.4 ± 0.06 kg/d) but not in batch 2 (1.1 ± 0.09 kg/d vs. 1.0 ± 0.06 kg/d). In conclusion, prolonged full CCC led to heavier calves with higher preweaning growth and a lower postweaning growth than calves separated from the dam shortly after birth. Consequences of CCC for metabolic and inflammatory variables were limited, except for a greater serum NEFA concentration and a decline in serum IGF-1 concentration from pre- to postweaning for the FC calves.
在奶牛 - 犊牛接触（CCC）系统中，奶牛和犊牛长时间待在一起，与传统奶牛系统中奶牛和犊牛早期分离相比，这使得犊牛有更多的吮乳机会，加强了母犊联系。CCC系统中延长的吮乳时间与犊牛的更大生长相关，尽管关于延长吮乳对犊牛体况、代谢和炎症变量影响的知识有限。本研究旨在评估至少12周进行CCC随后逐渐断奶和分离的犊牛的生长、背膘厚度、能量代谢和炎症状态，并与出生后13.5小时即与其母亲分离的犊牛进行比较。在2个实验批次中，根据奶牛的胎次和品种（瑞典荷斯坦或瑞典红）以及犊牛的性别和品种（奶牛或奶牛与肉牛的杂交品种）对治疗组分配进行了平衡。犊牛在平均12.5周龄开始为期10天的围栏断奶之前，可与母亲充分接触（FC组，n = 21），在此期间吮乳机会逐渐减少。传统饲养的不与母亲接触的犊牛（NC组，n = 22）每天从奶桶中获得8升全脂牛奶，最初单独饲养1周，随后进行群体饲养。NC组犊牛在12.2周龄时在10天内逐渐断奶。此外，FC组和NC组犊牛均可自由采食精饲料和粗饲料。断奶前FC组犊牛的生长速度大于NC组犊牛（1.4 vs. 1.1±0.06 kg/d；最小二乘均值±标准误）。在断奶前期，治疗组之间血清葡萄糖、胰岛素、IGF - 1和触珠蛋白浓度无差异，但FC组犊牛的非酯化脂肪酸（NEFA）浓度高于NC组犊牛。断奶后，FC组和NC组犊牛的血清葡萄糖、胰岛素和NEFA浓度均下降。FC组犊牛断奶后血清IGF - 1浓度下降，而NC组犊牛未下降。断奶后，尽管FC组犊牛在第1批次中的断奶后生长速度低于NC组犊牛（1.1±0.06 kg/d vs. 1.4±0.06 kg/d），但在第2批次中并非如此（1.1±0.09 kg/d vs. 1.0±0.06 kg/d），FC组犊牛仍保持其体重优势且背膘厚度高于NC组犊牛。总之，与出生后不久即与母亲分离的犊牛相比，长时间的完全CCC导致犊牛体重更重，断奶前生长速度更高，断奶后生长速度更低。CCC对代谢和炎症变量的影响有限，除了FC组犊牛血清NEFA浓度更高以及断奶前后血清IGF - 1浓度下降外。
