Effects of dietary glucogenic precursors and fat on feed intake and carbohydrate status of transition dairy cows.
Twenty-four multiparous Holstein cows were used to determine the effects of dietary fat and glucose precursors on energy status and lactation. The treatment group (T) received 409 g/d (DM basis) of a combination of calcium salts of fatty acids, calcium propionate, and propylene glycol. The control group (C) received 409 g/d of a mixture of calcium salts of fatty acids and ground barley from 14 +/- 0.9 g/d before until 21 d after calving. Dry matter intake was greater (16.1 vs. 13.6 +/- 1.3 kg/d) for T than C during the last week prepartum and did not decrease for T from the previous week, whereas, in C, DM intakes decreased by 3.2 kg/d. Production of milk and milk fat did not differ. There was a tendency for lower protein and increased lactose concentrations in milk from T cows. Milk fat percentage was lower in T at d 7 (5.5 vs. 6.4 +/- 0.5%) and 28 (4.4 vs. 5.5 +/- 0.5%) of lactation. Liver lipid content was numerically lower (7.9 vs. 9.2 +/- 0.9%) and glycogen content was significantly higher (2.4 vs. 2.0 +/- 0.1%) in T vs. C cows on d 7 of lactation. Concentrations of nonesterified fatty acids were lower in blood of T cows on d 2 and 7 of lactation. Over all time points, blood glucose concentrations were higher in T cows pre- (70.75 vs. 62.1 +/- 1.3 mg/dL) and postpartum (60.1 vs. 56.2 +/- 1.1 mg/dL). Insulin concentrations in blood were greater for T (397 vs. 314 +/- 48 pg/mL) both pre- and postpartum. Feeding glucose precursors in combination with rumen inert lipids, compared with feeding barley in combination with the lipids for 2 wk before parturition and 3 wk postpartum helped avoid prepartum feed intake depression and increased blood glucose and insulin and decreased blood NEFA.
Galisteo, New Mexico 87540, USA.
R S
RS
Patton
C E
CE
Sorenson
A R
AR
Hippen
D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D002417:Cattle / Q000502:physiology*; D004041:Dietary Fats / Q000008:administration & dosage*; D004435:Eating / Q000187:drug effects*; D004734:Energy Metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005934:Glucagon / Q000097:blood; D005947:Glucose / Q000096:biosynthesis*; D007328:Insulin / Q000097:blood; D007774:Lactation / Q000502:physiology*; D007785:Lactose / Q000032:analysis; D008055:Lipids / Q000032:analysis; D008099:Liver / Q000737:chemistry; D008892:Milk / Q000737:chemistry; D008894:Milk Proteins / Q000032:analysis; D049590:Postpartum Period; D013997:Time Factors
D001786:Blood Glucose; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D008055:Lipids; D008894:Milk Proteins; D005934:Glucagon; D005947:Glucose; D007785:Lactose