Prepartum and/or postpartum supplementation with monensin-molasses multinutrient blocks to optimize fertility and calf performance in primiparous beef cows

Abstract

Objective: Pregnant Nelore heifers (n = 417) were used to evaluate the effects of supplementation with monensin-molasses multinutrient block (B) during pre and/or postpartum on reproductive and progeny performance.Methods: Heifers were allocated in four treatments: i) CC: heifers received control supplement (C) in loose meal form (0.06% of body weight [BW] offered daily before and after parturition; n = 108); ii) CB: received C before parturition and B (0.07% of BW offered weekly after parturition; n = 117); iii) BC: received B before and C after parturition (n = 103) and iv) BB: received B before and after parturition (n = 89). During pre and postpartum periods, concentration of metabolites/hormones and cow/calf performance was evaluated over time. Cows were synchronized twice for fixed timed artificial insemination (FTAI) using an estradiol/progesterone-based protocol. Data was analyzed by orthogonal contrasts (C).Results: B increased pregnancy at first FTAI (p = 0.04) and overall pregnancy rate (C1: CC vs BB+BC+CB; p = 0.05). Supplemented cows had greater body condition score (BCS) only at parturition (D0; p = 0.04) and at D40 (p = 0.02). B increased BW (p = 0.03), glucose concentrations (p = 0.01) and subcutaneous fat thickness (p = 0.03) only at D40. Concentrations of insulin were higher in supplemented cows (p = 0.008). Calves born by cows supplemented before and after parturition (C2: BB vs BC+CB) were heavier at 80 (p<0.001), 120 (p<0.001), 170 (p = 0.002) and 210 (p = 0.02) days old.Conclusion: Regardless of period of treatment, block supplementation increased pregnancy at first FTAI and overall pregnancy rate. Additionality, block supplementation during both pre and postpartum periods improved progeny weight until weaning. Block supplementation can be a tool to optimize fertility and calf performance in Nelore primiparous cows.

Uso de monensina na alimentação e seu efeito na reprodução em vacas

“…No entanto, apesar das distinções observadas no metabolismo ruminal entre as novilhas que receberam monensina e aquelas que não receberam, é possível que os níveis de propionato alcançados nas vacas tratadas não tenham sido suficientes para afetar a taxa de prenhez, uma vez que as demandas nutricionais podem variar entre as duas categorias de animais, conforme sugerido por Fox et al (1992). Lima et al (2022) observaram resultados diferentes das pesquisas anteriores, quando estudaram a suplementação com monensina-melaço em blocos de multinutrientes em 417 novilhas Nelore, verificaram a partir desse estudo aumento do escore de condição corporal (ECC) no momento do parto, melhorando a gestação na primeira inseminação artificial em tempo fixo (IATF), bem como a taxa de prenhez ao final da estação de monta (EM).…”

“…O manejo nutricional é amplamente reconhecido como um dos principais elementos que influenciam de maneira significativa a eficiência reprodutiva em bovinos de corte (D'occhio et al 2019;Wiltbank et al 1962;Catussi et al, 2022). As propriedades rurais de caráter comercial no Brasil apresentam uma notável concentração de ocorrências de nascimentos durante o período da estação seca, bem como durante a transição para a estação chuvosa.…”

Metabolic imprinting in beef calves supplemented with creep feeding on performance, reproductive efficiency and metabolome profile

“…These enhancements in early-life ruminal metabolism could lead to improved feeding behavior and accelerated calf growth rates. Such changes hold significant implications for long-term productivity outcomes in beef cattle systems 34 , 53 , 54 . Reviewed by Lech et al 55 , the metabolic effects of different feeding regimes in Holstein–Friesian cows post-calving were evaluated, revealing distinct metabolic adaptations in grass-fed versus grain-fed cows.…”

“…Notably, there were no significant differences in productivity parameters, such as BW, BFAT, and BCS at Days 360 and 408. The equivalence in BW could be attributed to a lower ADG during the post-weaning period, which can be explained by the challenges posed by a dry season with limited forage availability 34 . Furthermore, no differences were found between treatments when uterine and follicular diameter were evaluated.…”

“…Moreover, on days 220 and 360, the rump fat thickness (RFAT) was assessed by carcass ultrasonography (Aloka 500 SV; Hitachi Aloka Medical America, CT, USA). RFAT measurements were taken when the transducer was linearly positioned between hooks and pins at the sacral examination site and moved slightly to obtain the correct ultrasound image, allowing for the visualization of the superior limit of the biceps femuris muscles 33 , 34 . Carcass ultrasound examinations were performed by a single technician, and images were processed using the Lince software (M & S Consultoria Agropecuária Ltda., SP, Brazil).…”