Body condition score at parturition and postpartum supplemental fat effects on cow and calf performance1

Abstract

Three-year-old Angus x Gelbvieh beef cows nutritionally managed to achieve a BCS of 4 +/- 0.07 (479.3 +/- 36.3 kg of BW) or 6 +/- 0.07 (579.6 +/- 53.1 kg of BW) at parturition were used in a 2-yr experiment (n = 36/yr) to determine the effects of prepartum energy balance and postpartum lipid supplementation on cow and calf performance. Beginning 3 d postpartum, cows within each BCS were assigned randomly to be fed hay and a low-fat control supplement or supplements with either high-linoleate cracked safflower seeds or high-oleate cracked safflower seeds until d 60 of lactation. Diets were formulated to be isonitrogenous and isocaloric, and safflower seed supplements were provided to achieve 5% of DMI as fat. Ultrasonic 12th rib fat and LM area were lower (P < 0.001) for cows in BCS 4 compared with BCS 6 cows throughout the study. Cows in BCS 4 at parturition maintained (P = 0.02) condition over the course of the study, whereas cows in BCS 6 lost condition. No differences (P = 0.44 to 0.71) were detected for milk yield, milk energy, milk fat percentage, or milk lactose percentage because of BCS; however, milk protein percentage was less (P = 0.03) for BCS 4 cows. First-service conception rates did not differ (P = 0.22) because of BCS at parturition, but overall pregnancy rate was greater (P = 0.02) in BCS 6 cows. No differences (P = 0.48 to 0.83) were detected in calf birth weight or ADG because of BCS at parturition. Dietary lipid supplementation did not influence (P = 0.23 to 0.96) cow BW change, BCS change, 12th rib fat, LM area, milk yield, milk energy, milk fat percentage, milk lactose percentage, first service conception, overall pregnancy rates, or calf performance. Although cows in BCS of 4 at parturition seemed capable of maintaining BCS during lactation, the overall decrease in pregnancy rate indicates cows should be managed to achieve a BCS >4 before parturition to improve reproductive success.

Body condition score of Nellore beef cows: a heritable measure to improve the selection of reproductive and maternal traits

“…In a dairy cattle study, Loker et al (2012) found an unfavourable genetic correlation between BCS and milk production that increased as the lactation period progressed: the higher the milk production, the worse the body condition of the cow. Conversely, Lake et al (2005) found no significant effect of cow BCS on the calf weaning weight.…”

“…Nevertheless, the existing evidence on the connection between BCS and pregnancy rate is controversial. Lake et al (2005) conducted a study with crossbred cattle and reported increased pregnancy rate in cows with high BCS, whereas Mulliniks et al (2012) found that BCS had no effect on the pregnancy rate. Furthermore, little is known about the variability of BCS in beef cows and whether such differences are heritable.…”

Modelo de simulação do desempenho reprodutivo de fêmeas bovinas de corte com base no escore de condição corporal

“…O peso vivo do animal é um indicador limitado para esse contexto por ter grande variabilidade entre raças e até mesmo entre rebanhos, além de ser uma medida que necessita de infraestrutura e deslocamento dos animais para ser aferida. Lake et al (2005) ressaltaram que o ECC é um indicador das reservas de energia na forma de tecido muscular e/ou adiposo que pode ser usado para suportar os processos fisiológicos durante períodos de aumento da demanda metabólica. O acúmulo de gordura corporal ocorre quando a ingestão de nutrientes é maior que as exigências para mantença e produção (Wettemann & Bossis, 1999;Lake et al, 2004) e a mobilização quando os animais se encontram em balanço energético negativo (Lake et al, 2004), ou seja, quando a ingestão de energia é menor que a demanda.…”

“…O acúmulo de gordura corporal ocorre quando a ingestão de nutrientes é maior que as exigências para mantença e produção (Wettemann & Bossis, 1999;Lake et al, 2004) e a mobilização quando os animais se encontram em balanço energético negativo (Lake et al, 2004), ou seja, quando a ingestão de energia é menor que a demanda. O ECC ainda é mencionado ao parto como o principal fator determinante do intervalo partoprimeiro cio e taxa de prenhez em vacas multíparas (Richardset al, 1986;Selk et al, 1988;Spitzer et al, 1995;Lake et al, 2005) e um confiável indicador do desempenho reprodutivo pós-parto em primíparas (Wettemann & Bossis, 1999;Morrison et al, 1999;DeRouen et al, 1994).…”

“…Níveis alimentares inadequados no período pré-parto ocasionam perdas de reservas corporais e aumentam o período parto-primeiro cio (Wiltbank et al, 1962;Richards et al, 1986;Spitzer et al, 1995). O escore de condição corporal ao parto (ECCPAR) é mencionado como o principal fator determinante do intervalo parto -primeiro cio, da taxa de prenhez (Selk et al, 1988;Spitzer et al, 1995;Lake et al, 2005), da duração do anestro pós-parto (Spitzer et al, 1995;Lalman et al, 1997, Looper et al, 2003Hess et al, 2005) e do intervalo de partos (Renquist et al, 2006). Segundo DeRouen et al (1994) registros do ECCPAR são um indicador confiável do desempenho reprodutivo pós-parto para parição de primavera em vacas primíparas.…”