Breed and Parity Effects on Energy Balance Profiles Through Lactation: Evidence of Genetically Driven Body Energy Change

Abstract

The aim of this study was to characterize patterns of energy balance through lactation of cows kept under constant feeding conditions. Danish Holstein, Danish Red, and Jersey cows were studied during consecutive lactations and remained on the same dietary treatment throughout. They were fed a normal (13.55 MJ of digestible energy/kg of dry matter) or a lower energy diet (12.88 MJ of digestible energy/kg of dry matter) ad libitum throughout lactation. Energy balance was calculated using the effective energy (EE) system in such a way that energy balance equated to body energy reserve change. In the EE system the energy values assigned to feeds are directly equivalent to the energy requirements of the animal; 1 MJ of EE supply has the same energy value as 1 MJ of lipid loss from the body. The resulting body energy change data were analyzed using a linear spline model. There was no evidence to suggest that different combinations of breed and parity required different knot placements. The Holstein mobilized significantly more body energy in early lactation than the Danish Red and Jersey breeds. Parity 1 cows mobilized significantly less than parity 2 and 3 cows. There was a significant interaction between breed and parity in the first half of lactation due to parity 1 Jersey cows having a greater mobilization than would be expected of the difference between parities in the other breeds. As lactation progressed, the differences between parities and between breeds decreased. Cows on the higher energy diet had a more positive energy balance. Within breed and parity, the following possible predictors of individual differences in body energy change were examined: fatness-corrected live weight, condition score at calving, and genotype. There was no difference in the predicted cow effect or residual energy balance profile when grouped according to quartiles of corrected live weight or according to condition score at calving. During the period of most negative energy balance (d 14) there was no significant relationship between live weight and intake, suggesting that, within diet type, the systematic patterns of body energy change through lactation in cows that were kept under stable and sufficient nutritional conditions cannot be accounted for by environmental factors such as constrained intake or condition score at calving. Thus, these patterns appear to have a genetic basis. The proportion of the phenotypic variation (remaining after accounting for fixed effects) accounted for by additive genetic effects varied through lactation from 4.2 to 13.0%. Genetic correlations between early and late lactation energy balances were low and close to zero, suggesting that body energy changes in early and late lactation are genetically independent traits.

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

“…This evidence, together with the evolutionary basis for the strategic use of body reserves, strongly suggests that the observed patterns of change in body fatness through the reproductive cycle have a major genetic component (Friggens, 2003;Roche et al, 2007). Recently, direct evidence for genetically driven mobilisation of body energy reserves in dairy cows in early lactation has been provided (Friggens et al, 2007). Genetically driven body energy change is defined as that which would occur in cows when kept in an environment that was in no way constraining (Friggens et al, 2004b).…”

Genetic and non-genetic factors related to the success of artificial insemination in dairy goats

“…So both observations could suggest that QPY could be related to pre-partum body condition score which is known to affect fertility (Walsh et al, 2011). This relation could be positive for multiparous female and negative for younger females because of differences in energy balance, as demonstrated on cows by Friggens et al, 2007. The effect of modalities of treatment for induction and synchronization of oestrus was important despite the difficulties to gather reliable information and the imperfection of the database structure that did not allow the declaration of simultaneous treatments (such as the combination of light and hormonal treatment which is known to be practised on farm).…”

Effects of live weight adjusted feeding strategy on plasma indicators of energy balance in Holstein cows managed for extended lactation

“…The E act is the energy required for activity of loose housed cows (MJ NEL/day), 0.01 corresponds to the 10% activity for voluntary activity (MJ ME/kg) (NRC, 2001), and 'b' is the coefficient of conversion from ME to NEL, equal to 0.65. The energy used for growth was not included as it has been shown to be <1% of the energy output and only for the first and second parity (Friggens et al, 2007). The cows were not inseminated before 8 months of lactation so the energy for conception was not included in the calculation as the period studied was from calving to insemination.…”