The impact of neonatal nutrition on the health, welfare and productivity of Holstein dairy calves.

Curtis, Gemma The impact of neonatal nutrition on the health, welfare and productivity of Holstein dairy calves. PhD thesis, University of Liverpool.

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Abstract

Dairy calves in the U.K. are currently reared on ‘least cost’ principles, with minimal milk feeding and early weaning to solid foods. This has been described as maintaining the calf in ‘a state of chronic hunger’. As well as repercussions on calf health, growth and welfare, human studies suggest that underfeeding the newborn is a major risk factor for metabolic disease in the adult. The aims of this study were to determine current dairy calf rearing practices across the U.K., to investigate the performance of Holstein heifer calves fed increased milk replacer (MR) compared to restricted volumes, and to determine the impact of this on key performance indicators (KPIs) of these animals as calves and growing heifers. A postal questionnaire was offered to one thousand U.K. dairy farmers to determine current calf rearing practices. The response rate was 72% and revealed that housing and feeding practices were variable between farms. The majority of farmers (93%) fed restricted volumes of milk or milk replacer to their pre-weaned calves. The body weight, withers and loin height, heart and belly girth, crown to rump length, hock-fetlock length and body condition score (BCS) were recorded weekly from birth to 12 weeks and monthly from 12 weeks until conception in two groups of Holstein heifer calves on one commercial dairy farm in the north-west of England, U.K. Calves were assigned to a restricted, Group R (n = 50) or ad libitum, Group A (n = 50) MR feeding strategy from birth until weaning. Growth rates were greater for Group A (0.72kg/day) from birth until 3 weeks than Group R (0.17kg/day). Body condition score increased for Group A during this period (0.1 points) while it decreased for Group R (0.3 points). Thereafter, growth rates were similar between dietary groups although no catch-up growth was observed for Group R animals. Changes in morphometric measures were greater for Group A calves than Group R from birth to 12 weeks. From 12 weeks of age onwards, dietary group differences in morphometric measures disappeared but body weight differences remained until conception. The glucose metabolism and insulin sensitivity of a subset of heifer calves (n = 6 Group A, n = 6 Group R) was investigated at 3, 12 and 39 weeks of age and was shown not to be affected by dietary group. The carcass composition of Holstein bull calves assigned to one of the two dietary groups was assessed. Calves were studied at birth (n = 3), 3 weeks, 9 weeks or 12 weeks (n = 3 per dietary group at each age). Carcass composition was assessed using spiral CT technologies. Group A calves had greater internal adipose deposition at all ages but there was no difference in carcass associated adipose tissue. The age at puberty, first service and conception was between 2 and 3 weeks lower for Group A animals than for Group R. Increased MR feeding of Holstein heifers allows for greater growth rates and earlier entry into the milking herd.

Item Type:	Thesis (PhD)
Additional Information:	Date: 2015-09 (completed)
Subjects:	?? Q1 ?? ?? S1 ??
Depositing User:	Symplectic Admin
Date Deposited:	27 Jan 2016 14:49
Last Modified:	17 Dec 2022 01:45
DOI:	10.17638/02030959
URI:	https://livrepository.liverpool.ac.uk/id/eprint/2030959