Recovery in the size of the overall dairy herd in Great Britain has been held back by lower youngstock numbers following recent poor milk prices, said AHDB.
The size of the herd dropped by 1.6% (42,000 head) between the start of 2016 and the start of 2017, according to data from the British Cattle Movement Service. This is the largest year-on-year decline recorded in recent years.
The number of dairy heifers under 12 months old has been behind year-earlier levels for six months, reflecting a trend towards using a greater proportion of beef sires for dairy cows, said AHDB.
It said that while retention rates, and therefore milk prices, will be important, this smaller supply of replacement heifers will continue in the coming months.
However, there are 5% more animals between 18 and 36 months of age, which should provide a boost to milk production over the next 12 months if retained.
The numbers of both older (nine-year-old) and prime (three- to four-and-a-half-year-old) animals are below April 2016 levels, but while the number of older animals has recovered slightly since January, prime animals have shown little movement, remaining 4.6% (33,000 head) below April 2016.
Meanwhile, the rate at which the number of producers in England and Wales is dropping has seen a sharp increase between May and June this year, down by 26 holdings.
This is the largest monthly drop since September 2015, according to AHDB figures, and means the number of producers in England and Wales was down 1.6% in June 2017, year on year.
The number now stands at 9,406, compared to 12,867 in June 2007.