How much to feed an Australian Shepherd: for family and sport

MDR1 mutation: important when your Aussie has diarrhoea

Many Australian Shepherds carry a change in the MDR1 gene (also called ABCB1). The gene controls a transport protein that keeps certain drugs out of the brain. Washington State University puts the frequency in the Australian Shepherd at about 50 per cent. A study of 145 Aussies in Israel (BMC Veterinary Research, 2017) found an allele frequency of 31.4 per cent; 9 per cent of the dogs carried two copies of the change. Only a genetic test shows whether your dog is affected.

This matters for feeding because diarrhoea is often treated with remedies from the home medicine cabinet. According to Washington State University, loperamide (e.g. Imodium) causes neurological signs of poisoning in dogs with the MDR1 mutation even at the dose used for diarrhoea, and should be avoided in them altogether. Feeding also plays a role with some wormers: in a case report from the University of Giessen (2019), an MDR1-affected Aussie was given a handful of dry food half an hour before a deworming product for which fasting is recommended. It trembled, was restless, panted and had to be hospitalised.

• Have the MDR1 status checked with a genetic test and note the result in the vaccination record.
• For diarrhoea, no loperamide from the medicine cabinet – start with a bland diet, and see the vet if there are warning signs.
• Follow the feeding instructions in a wormer's package leaflet carefully, for example whether your dog needs to have an empty stomach.

Herding dog or family dog: activity decides

The FCI standard describes the Australian Shepherd as a herding dog for farm and ranch. How much an Aussie needs therefore depends above all on whether it actually does this work. At 25 kg, a neutered dog with normal exercise needs 1,250 kcal, with regular dog sports 1,565 kcal and as a herding dog working every day about 2,350 kcal. An Aussie that only does agility at weekends usually belongs in the “Normal” or “Active” row.

The MSD Veterinary Manual points out that working dogs may need more than a maintenance ration – depending on the dog and its workload. For working days, it recommends feeding only a smaller part of the daily ration before work, around a third, and the rest afterwards.

• Feed more on training and working days and less on rest days – what matters is the weight over several weeks.
• About a third of the ration before training or herding, the rest afterwards.
• Weigh every two weeks and feel the ribs: an athletic Aussie is lean, but not bony.

Aussie puppies: steady growth

At up to about 29 kg, the Australian Shepherd sits between medium-sized and large breeds. According to the MSD Veterinary Manual, the skeleton of small and medium-sized breeds matures at 8 to 12 months, but in large breeds only at 10 to 16 months. A steady weight curve matters more than rapid gains; weigh your puppy regularly and adjust the amount accordingly. Until about three months it gets four meals, after that three.

Rare, but described in Aussies, is an inherited disorder of vitamin B12 absorption (Imerslund-Gräsbeck syndrome). Affected puppies usually show the first signs at 8 to 12 weeks: they are listless, eat poorly and do not gain weight. More food does not help then – your vet can measure the B12 level.

The puppy feeding calculator works out the exact amount by age and current weight.