The effect of early-lactation feeding strategy on the lactation performance of spring-calving dairy cows.
The objective of this study was to establish the influence of daily herbage allowance (DHA) and supplementation level offered to spring-calving dairy cows in early lactation on animal performance throughout lactation. Sixty-six Holstein-Friesian dairy cows were randomly assigned to a 6-treatment grazing study. The treatments comprised 3 DHA levels (13, 16, and 19 kg of DM/cow; >4 cm) and 2 concentrate supplementation levels (0 and 4 kg of DM/cow per day). Treatments were imposed from February 21 to May 8 (period 1; P1). During the subsequent 4-wk (period 2; P2), animals were offered a DHA of 20 kg of DM/cow and no concentrate. Subsequently, all animals grazed as a single herd to the end of lactation. Sward quality was homogeneous throughout lactation. A low DHA increased sward utilization (+14%) but reduced milk, solids-corrected milk, protein, and lactose yields compared with a high DHA during P1. Concentrate supplementation significantly increased milk, solids-corrected milk, fat, protein, and lactose yields during P1. The positive effect of concentrate supplementation remained throughout P2. A total concentrate input of 380 kg of DM/cow increased total lactation milk (+432 kg), solids-corrected milk (+416 kg), fat (+18 kg), protein (+15 kg), and lactose (+23 kg) yields. Greater P1 body weights were recorded when a high DHA and concentrate were offered. The P1 treatment had no effect on body condition score throughout lactation. The results indicate that offering a low DHA in early spring does not adversely affect total milk production, body weight, or body condition score, and offering concentrate results in a greater total lactation milk production performance.
Kennedy
E
E
Dairy Production Research Centre, Teagasc, Moorepark, Fermoy, Co. Cork, Ireland. Emer.Kennedy@teagasc.ie
O'Donovan
M
M
O'Mara
F P
FP
Murphy
J P
JP
Delaby
L
L
D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena / Q000502:physiology*; D000818:Animals; D001823:Body Composition; D001824:Body Constitution; D002417:Cattle / Q000502:physiology*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D007774:Lactation / Q000378:metabolism / Q000502:physiology*; D008892:Milk / Q000737:chemistry* / Q000378:metabolism; D009751:Nutritional Requirements; D011897:Random Allocation; D013997:Time Factors; D015430:Weight Gain