Jerseys cannot compare
Jerseys present unique challenges with respect to
feeding, breeding and milk processing. The breeds future
was debated at a recent DRC conference held at
CEDAR. Marianne Curtis reports
EVIDENCE unearthed by one Reading University researcher suggests that applying Holstein rationing principles to Jerseys is flawed. Jerseys have higher intakes/kg bodyweight, greater susceptibility to milk fever and higher dry period maintenance requirements than their black and white cousins.
Speaking at DRCs conference The Jersey – A Golden Future held at CEDAR, Chris Reynolds said rationing Jerseys as mini-Holsteins is not enough, but there is little experimental data on Jerseys to assist with feeding.
"One study showed that Jersey dry matter intake was 3.8-3.9% of bodyweight compared with large frame cows where it was only 3-3.2%. Intakes of 5% of bodyweight are possible for Jerseys.
"Relative to larger cows, intake of Jerseys is 83% and bodyweight 66%. This shows that even for low yielding Jerseys, intake cant be predicted from bodyweight and milk yield using equations developed for Holsteins," said Dr Reynolds.
High intakes are sometimes associated with lower digestibility because feed passes through the digestive system more quickly, but digestibility in Jerseys is as high as in Holsteins, he discovered.
"Despite a faster rate of feed passage in Jerseys than in Holsteins, digestibility remains the same. This may be because Jerseys are more efficient at chewing and ruminating forage."
High quality forage is particularly important for Jerseys because of their milks high fat content, said Dr Reynolds. "Milk fat is derived from long chain fatty acids in blood or synthesised in the udder.
"Jerseys synthesise a higher proportion of milk fat in the udder than Holsteins. Forage supplies nutrients required for udder milk fat synthesis so Jerseys are less tolerant of rationing errors and lower quality forage than Holsteins."
US information suggests that Jersey rations should have a minimum acid detergent fibre (ADF) level of 21%, minimum digestibility of 65% and maximum neutral detergent fibre (NDF) level of 46%. UK data is not available and there are some difficulties with using US data, he warned.
"It is difficult to relate US data to the UK because NDFs in UK grass-based rations usually exceed the US recommended maximum. Aim to make grass silage with a minimum of 30% dry matter to maximise intakes in Jerseys."
Intakes must also be maintained at a higher level/kg bodyweight for Jerseys than Holsteins in the dry period, said Dr Reynolds. "Research shows that basing Jersey dry cow rations on Holstein data led to weight loss in Jerseys.
"Jersey feeding levels had to be increased by 30% to avoid catastrophic weight loss. This difference may be because Jerseys are leaner animals than Holsteins."
Feeding anionic diets in the dry period is another area where special attention needs to be given to Jerseys, explained Dr Reynolds.
"Jerseys have fewer vitamin D receptors in their gut – which are responsible for increasing calcium absorption in early lactation – making them more susceptible to milk fever."
When cation-anion differences are being adjusted in transition rations, he suggested using a target urine pH of 5.8-6.2, lower than that for Holsteins where the target is 6.2-6.7.
• High intakes/kg bodyweight.
• Require high quality forage.
• More susceptible to milk fever.