Effects of an individual weight-adjusted feeding strategy in early lactation on milk production of Holstein cows during extended lactation

Abstract

Extending lactation by voluntarily delaying rebreeding aims to improve fertility and milk production in the modern dairy cow. Previous studies have shown that increased energy concentrations in the ration induced greater total milk yield and lactation persistency defined by the duration and the shape of the lactation curve. In this paper, we hypothesized that increasing the supply of energy during the early lactation mobilization period would have a positive carryover effect on milk production during extended lactation. A total of 53 Holstein cows completed a 16-mo lactation, including 30% primiparous cows. The cows were divided into 2 feeding strategies: half of the cows received a high-energy density diet (HD) in early lactation followed by a lower-energy density diet (LD; strategy HD-LD). The change in diet was defined individually after 42 d of lactation, and when the live weight (LW) gain of the cow was ≥ 0 based on a 5-d average. The other half of the cows were fed the LD diet during the entire lactation (strategy LD-LD). Both groups received 3 kg of concentrates per day during milking. Weekly milk composition (fat, protein, lactose, and somatic cells), daily milk production, daily feed intake, daily LW, and body condition score every second week were recorded. The fda package of R was used to model the curves of these different variables for the 53 cows that had a lactation over 400 d. The fitted values of these curves and the associated slopes were then compared for parity and treatment effects using a linear mixed-effects model. The HD-LD and LD-LD cows had a similar length of lactation (461 ± 7 d). The HD diet reduced the intensity of the mobilization period and increased the milk production of the multiparous cows in early lactation compared with the cows fed the LD diet. The primiparous cows used the extra energy to grow and gain weight, but not to produce more milk. After the shift in diet, the treatment had little short-term carryover effect on milk yield or LW, but it affected the slopes of some curves. From 0 to 50 d from shift, milk fat content of the LD-LD cows decreased faster than that of the HD-LD cows whereas milk lactose increased. From 250 to 350 d from shift, the energy-corrected milk decreased faster for the HD-LD cows than for the LD-LD cows. The lactose content in milk decreased faster for the LD-LD cows than for the HD-LD cows, and the fat content in milk was significantly higher for the primiparous HD-LD than for the primiparous LD-LD cows. In conclusion, the supply of extra energy during the mobilization period had a 300-d negative carryover effect on lactation persistency.

Good sensory quality and cheesemaking properties in milk from Holstein cows managed for an 18-month calving interval

“…The steep decline observed here in milk production in the final part of the extended lactation period (i.e., 300 to 420 DIM) for multiparous cows diminishes the difference in overall production as a result of parity. Still, the total milk yield was higher for multiparous cows (Gaillard et al, 2016b).…”

“…The observed higher milk production for multiparous cows compared with primiparous is well-known, as multiparous cows have a higher energy intake as a consequence of a higher DMI (Gaillard et al, 2016b). Furthermore, superior lactation persistency for primiparous cows compared with multiparous has previously been reported for cows undergoing 12-, 15-, or 18-mo CInt (Rehn et al, 2000;Österman and Bertilsson, 2003).…”

“…The cows were blocked according to expected calving date and parity and randomly allocated to 2 feeding strategies at calving (Gaillard et al, 2016b). In short, the high-low energy diet strategy (HD-LD) refers to cows that received a 50:50 forage-to-concentrate partial mixed ration with a high energy density (HD; 7.81 MJ of NE L /kg of DM) until they reached at least 42 d of lactation and a live weight gain ≥0 kg/d on a 5-d average, and then individually shifted to a diet with a lower energy density (LD, 7.49 MJ of NE L /kg of DM), consisting of 60:40 forage-to-concentrate partial mixed ration.…”

“…For both groups the mixed part of the diet was offered individually and ad libitum, and each cow was provided 3 kg of concentrate per day at the AMU. For detailed information on the feeding experiment and diet composition, see Gaillard et al (2016b).…”

Effect of Delayed Insemination on Holstein Cows’ Reproductive Performance

“…The cows had access to water and an automatic milking system (AMS; DeLaval AB, Tumba, Sweden) and were fed partially mixed rations with complementary concentrates supplied during visits in the AMS. More information on the setting of the experiment during the extended lactation, details about the rations and milk production can be found in the study of Gaillard et al [10,11]. …”