title: Ultrasonography to investigate the effect of supplementing whole milk with complex carbohydrates and specific amino acids on curd retention in the abomasum of dairy calves.
abstract: OBJECTIVE
  To determine whether the retention time of curd in the abomasum of calves was influenced by supplementing milk with a plant-derived carbohydrate and amino acid supplement, evaluated non-invasively using ultrasonography.
  
  
  METHODS
  Female dairy calves aged between 2-6 days of age were sourced from a commercial farm in March 2013. All calves were fed whole milk until weaning (4 L per day); 21 calves were supplemented with a probiotic until 18 days of age, and thereafter with a plant-derived complex carbohydrate and amino acid supplement until weaning, and 22 calves were just fed whole milk. Treatment groups were balanced for age, weight and breed. At 9-14, 24-29 and 52-57 days of age, the abomasum of each calf was examined using ultrasonography immediately before and after feeding, 1 and 2 hours after feeding, and then at 30 minute intervals until curd was no longer visible in the abomasum. Abomasal volume and curd size were recorded to assess retention time of curd in the abomasum.
  
  
  RESULTS
  At 9-14 days of age, mean retention time of curd in the abomasum was similar (4.6 hours) in both groups. At 24-29 days of age, when the supplemented calves had been receiving the supplement for approximately 10 days, mean curd retention time was longer by 1.4 (SE 0.28) hours in supplemented compared with unsupplemented calves (p<0.001). At 52-57 days of age, mean retention time was longer by 0.7 (SE 0.34) hours compared to unsupplemented calves (p=0.05).
  
  
  CONCLUSIONS
  Using ultrasonography, changes in abomasal content could be followed non-invasively over time and it was demonstrated that the plant-derived complex carbohydrate supplement increased the curd retention time in the abomasum. We speculate that the increased retention time enables an increased availability of nutrients following a more complete digestion of milk, thereby improving animal performance.
authors.affiliation: a AgResearch Ltd, Ruakura Research Centre , Private Bag 3123, Hamilton 3240 , New Zealand.
authors.forename: K
authors.initials: K
authors.lastname: Singh
authors.affiliation: a AgResearch Ltd, Ruakura Research Centre , Private Bag 3123, Hamilton 3240 , New Zealand.
authors.forename: S R
authors.initials: SR
authors.lastname: Leath
authors.affiliation: a AgResearch Ltd, Ruakura Research Centre , Private Bag 3123, Hamilton 3240 , New Zealand.
authors.forename: H V
authors.initials: HV
authors.lastname: Henderson
authors.affiliation: b AgResearch Ltd, Grasslands Research Centre , Private Bag 11008, Palmerston North 4442 , New Zealand.
authors.forename: A J
authors.initials: AJ
authors.lastname: Molenaar
authors.affiliation: a AgResearch Ltd, Ruakura Research Centre , Private Bag 3123, Hamilton 3240 , New Zealand.
authors.forename: T J
authors.initials: TJ
authors.lastname: Watson
authors.affiliation: b AgResearch Ltd, Grasslands Research Centre , Private Bag 11008, Palmerston North 4442 , New Zealand.
authors.forename: D
authors.initials: D
authors.lastname: Pacheco
authors.affiliation: a AgResearch Ltd, Ruakura Research Centre , Private Bag 3123, Hamilton 3240 , New Zealand.
authors.forename: C D
authors.initials: CD
authors.lastname: McMahon
mesh_terms: D000018:Abomasum / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000502:physiology; D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology; D002417:Cattle / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D019587:Dietary Supplements; D005260:Female; D005772:Gastrointestinal Transit; D008892:Milk; D019936:Probiotics / Q000627:therapeutic use; D014463:Ultrasonography / Q000662:veterinary
chemical_list: D000596:Amino Acids; D004040:Dietary Carbohydrates
keywords: Ultrasonography; amino acid diet supplement; carbohydrate; curd; dairy calves; milk; retention time