Restrição alimentar e atividade ovariana luteal cíclica pós-parto em vacas girolanda

Abstract

RESUMO -Objetivou-se neste trabalho verificar se a restrição alimentar no pós-parto em vacas Girolanda, multíparas, de bom escore de condição corporal (ECC = 3,5 a 4,5) ao parto será suficiente para impedir o reinício da atividade ovariana luteal cíclica (AOLC) pós-parto. Os animais foram distribuídos em três tratamentos: Grupo I (n = 15), mantença; Grupo II (n = 10) e Grupo III (n = 13), sendo que os grupos II e III receberam restrição alimentar até 90 e 180 dias pós-parto, respectivamente. As pesagens e avaliações do ECC foram efetuadas logo após o parto, e depois semanalmente. A AOLC foi avaliada por palpação retal, observação de cio e concentração de progesterona no leite. Os intervalos do parto ao primeiro cio foram de 53,1, 63,2 e 51,2 dias (P>0,05), respectivamente para os Grupos I, II e III, que apresentaram perdas de peso de 7,3 kg, 57,0 kg e 63,7 kg nesse período; e de 14,2 kg, 63,8 kg e 78,4 kg do parto até 90 dias pós-parto, repectivamente. Em vacas Girolanda de bom escore de condição corporal ao parto, a perda de 15,2% do peso nos três primeiros meses de lactação, e de 16,3% do peso até 180 dias pós-parto, não é suficiente para atrasar o reinício ou interromper a AOLC nos respectivos períodos.Termos para indexação: condição corporal, ciclo estral, bovinos, subnutrição. LOW LEVEL OF NUTRITION AND OVARIAN LUTEAL CYCLIC ACTIVITY POSTPARTUM IN CROSSBRED (HOLSTEIN X ZEBU) COWSABSTRACT -The objective of this study was to evaluate the effect of weight loss on postpartum cross bred Holstein x Gir (HZ) cows in good body score condition (BSC = 3.5 to 4.5) at calving on the delay of beginning or on maintenance of ovarian luteal cyclic activity (OLCA). Cows were distributed in three treatments: Group I (n = 15), maintenance; Group II (n = 10) and Group III (n = 13); Groups II and III were feed restricted until 90 and 180 days postpartum, respectively. The weight and BSC were measured after calving and then weekly. The OLCA was evaluated by rectal palpation, estrous detection and milk progesterone level. Intervals from the calving to first estrous were 53.1, 63.2 and 51.2 days (P > 0.05), respectively, for the Groups I, II and III; weight loss were of 7.3 kg; 57.0 kg and 63.7 kg up to the first estrous, and of 14.2 kg, 63.8 kg and 78.4 kg up to 90 days postpartum, for the Groups I, II, and III, respectively. In cross bred (HZ) cows in good body score condition at calving, the weight loss of 15.2% of body weight in the first three months of milking, and of 16.3% up to 180 days postpartum do not arrest the beginning or impair the maintenance of OLCA.

Nutritional, behavioral and performance parameters of F1 Holstein x Zebu cows at different lactation stages

“…According to Ferreira et al (2000), monitoring postpartum body weight in lactating cows is fundamental to ensure that body reserves will be adequate for cows to exhibit estrus and guarantee pregnancy. Furthermore, the authors reported that a BCS of 3.5 is ideal for cows to show estrus within 90 days postpartum.…”

“…In our study, the average BCS of 3.77 indicates that cows had sufficient energy reserves during lactation, which is a positive characteristic of F1 Holstein x Zebu cows. Ferreira et al (2000) reported that the desirable BCS in late lactation, close to the dry period of the cow, should be approximately 3.5, while at calving it should be 3.5 to 4.0. This assessment in late lactation is essential to prevent some cows from becoming too thin at drying off.…”

Feed restriction of F1 Holstein × Zebu cows in the final third of lactation modifies intake, nutrient digestibility, feeding behavior, and performance

“…Gross et al (2011) verified that the feed restriction of lactating cows for three weeks reduced their body weight. Ferreira et al (2000) stated that the monitoring of postpartum BW of lactating cows is fundamental so that they have sufficient reserves for the manifestation of estrus and guarantee of pregnancy. The same authors evaluated Girolando cows under conditions of feed restriction and concluded that the weight loss of 15.2% in the early lactation did not affect reproduction.…”

“…In this study, the mean value for BCS was 3.6 in the final third of lactation, even with the restriction of the diet supply, indicating that animals had sufficient energy reserves for the postpartum period. Ferreira et al (2000) reported that the desirable BCS in the final third of lactation, close to the drying time of the cow, is close to 3.5, whereas at the time of delivery it is 3.5 to 4.0. This evaluation in the final third of lactation is important to prevent some cows from getting too thin in the drying period, so there is no time to recover the necessary reserves during the dry period, aiming to reach a good body condition (Smith et al, 2017).…”

“…However, there are few studies about the restriction in diet supply (Ferreira et al, 2000) in crossbred Holstein × Zebu cows, mainly in specific phases of lactation. This crossbreed is responsible for most of the milk produced in Brazil (Santos et al, 2012) and is also recognized by its high potential of adaptation to various management conditions.…”