Effects of body condition at calving and feeding level after calving on LH profiles and the duration of the post-partum anoestrous period in beef cows

Abstract

An experiment was conducted to examine the effects of body condition at calving and feeding level post partum on the duration of the post-partum anoestrous period in beef cows. Forty-seven cows were used in each of 2 years. Cows were fed differentially before calving to achieve two levels of body condition at calving in November and December and were then fed at one of two levels of feeding post partum in a 2 X 2 factorial experiment. At calving, mean body condition scores were 2-85 (F) and 2-23 (T) (P < 0-001) while live weights were 521 kg and 457 kg (P < 0-001) for F and T cows respectively. After calving metabolizable energy intakes were 111 and 118 M]/ day (H) or 56 and 64 M]/day (L) in years 1 and 2 respectively. The H cows maintained live weight during the first 61 days of lactation while the L cows lost live weight (0-0 v. -1-1 kg/day, P < 0-001). The number of cows still acyclic on 1 May each year was higher (P < 0-01) on the TL treatment (10/24) compared with the other treatment combinations (FH: 2/22; FL: 5/22; TH: 2/24). The effect of level of feeding on the duration of the anoestrous period was significant in the T cows (89 v. 116 days for TH and TL cows respectively; P < 0-01) but not in the F cows (80 v. 89 days for the FH and FL cows respectively; P > 0-05). At 3 weeks post partum LH pulse frequency was higher in F than in T cows and tended to be higher in H than in L cows. At 6 and 9 weeks post partum LH pulse frequency was higher in H than L cows. LH pulse amplitude was higher in F than T cows at 3 weeks post partum and tended to be higher at 6 weeks post partum. It is concluded that both body condition at calving and feeding level after calving influence the duration of the post-partum anoestrous period with the effect of feeding level being particularly pronounced in thin cows.

Effect of pre-partum feed supplementation on post-partum ovarian activity, milk production and calf growth of small holder dairy Cattle in Cameroon

“…Though there is evidence that good pre-partum nutrition shortens the length of post-partum anoestrus (Selk et al 1988;Wright et al 1992), there are also conflicting reports which may be reflected in the interactions among pre-and post-partum nutrition, negative energy balance, BCS, milk yield and suckling, as well as other environmental factors that influence duration of postpartum anoestrus (Montielc and Ahuja 2005).…”

Nutritional sub-fertility in the dairy cow: towards improved reproductive management through a better biological understanding

“…There are very few experiments in cows where differences in body fatness are independent of body mobilisation (Villa-Godoy et al, 1990;Wright et al, 1992). However, there is evidence to be gleaned from other studies and other species.…”

“…The strongest direct evidence for an effect of body fatness independent of body mobilisation in cattle comes from the study of Wright et al (1992) who carried out an experiment with beef cattle which was designed to break the correlation between body fatness and rate of mobilisation. They applied two feeding levels in lactation to cows that had previously been made fat or thin (condition score at calving 2.85 and 2.23, respectively).…”

“…Numerous studies have shown a negative effect of body energy mobilisation in early lactation on days to first oestrus and conception rates (Berry et al, 2008). It is also clear that these effects occur independently of body fatness (Manning and Bronson, 1990;Wright et al, 1992). However, as pointed out by Leroy et al (2008a): 'the energy required to develop, mature and ovulate a follicle, to form a corpus luteum and to maintain early pregnancy is negligible compared to the energy demands of milk production and maintenance of lactation.…”

Management factors associated to the duration of postpartum anoestrus interval in Brown Swiss and Pirenaica beef cows

“…Como consecuencia de la práctica seguida en la explotación, las primíparas permanecieron con el ternero en acceso restringido. La influencia del nivel energético postparto sobre la duración del APP estuvo subordinada al efecto del nivel de alimentación recibido durante el último tercio de gestación, como también indicaron Wright et al (1992). El efecto de la nutrición postparto fue especialmente importante en animales jóvenes, tal y como han apuntado otros trabajos (Grimard et al, 1995).…”