Focus needed for successful hogget mating

09-03-2009 | Richard Rennie

Veterinarians are advising farmers to pay particular attention to pre-mating management of hoggets this year, with greater numbers due to be mated as farms restock sheep numbers.

Meat & Wool New Zealand figures last year showed a massive slide in hogget numbers, with flocks down 16% in the North Island and over 25% in the South.

Dairying, drought and poor returns had all contributed to the decline, but figures indicate a turn around this year.

Expectations are for 2.3 million hoggets to be mated this year, up from last year's low of 1.7m and closer to the 2007 figure of 2.5m.

Taumarunui veterinarian Clive Bingham says the King Country is looking at a re-stocking scenario after one of the hardest seasons the region had known. The poor spring of 2007 was followed by the direst spell for 100 years. The result was not only massive de-stocking in the region. Capital stock carried on had extremely low feed levels, resulting in light mating weights, lowered scanning percentages and poor birthing weights in ewes.

"The upside of more singles though and a good spring has been good lamb weights that put ewe hoggets in a good position to perform well when returns are also looking more promising," he says.

He says given most hoggets in the region are mated around May, there should be plenty of time to have them up to mating weights of 40kg-plus. However his past experience with hogget management has been that they have been treated as simply another mob, rather than getting the management attention they need as younger sheep.

"You have got to get the basics of good nutrition in place to really make hogget mating work, often they don't get enough attention here." Ironically this could be an issue in the region this year due to the abundance of feed, on some properties turning rank and losing quality.

Rather than simply drafting by sex at weaning and leaving all hoggets together, he advises his clients to pull out their top mobs of replacement hoggets as soon as possible into a separate mob for preferential feeding.

Parasite control needs to be a priority, given the lack of natural resistance to worm infestations that older ewes exhibit.

"If you are keeping a close eye on your hoggets, I advise using a shorter acting drench product." This will not compromise the development of natural worm resistance that older ewes enjoy.

Pfizer Animal Health parasitologist Dr Tom Watson says this autumn will see greater worm loadings on pastures than last thanks to regular rainfall, interspersed with warm, humid weather.

A reduction in cattle in some areas will also increase the worm loading on sheep, given cattle's ability to "hoover up" worm populations.

"With the conditions we had this summer, the under storey of grass will grow, and with their pickier feeding habits, hoggets will target this , and that is where the worm populations lie in greatest density."

He has recorded significant infestations of barber's pole (haemonchus) through the King Country region.

"Once you get infestations like this, they can linger for up to two months into warm autumn periods."

He regards barber's pole as the "vanguard" worm, closely followed afterwards by elevated ostertagia and trichostrongylus infestations.

He urges farmers to become more proactive in monitoring worm levels if they are intending to give preferential treatment to their ewe hoggets.

"In our own trials in the King Country, if we had not been doing FECs (faecal egg counts) we would never have picked up how intense the infestations were."

Last season Pfizer gained approval for Dectomax Injectable to be used over sheep, and Watson says its applicability this season is even greater than last.

"Last year we did not have the wet humid conditions, so while sheep had less feed, they also faced lower worm burdens going into autumn."

Dectomax has a proven history of good knock down on a broad spectrum of worms known to compromise sheep productivity, including haemonchus, ostertagia and trichostrongylus.

Farmers already treating their flock with a "5-in-1" vaccine can now add a low volume drench injectable to their programme with ease.

The short-acting nature of the injectable makes it ideal for selective treatment of ewe hoggets. With the rapid exit of its active ingredient Doramectin it is not as likely to interfere with the young ewe's development of resistance to worm infestations.

"The short half life in the animal means your sub lethal dose level stays there for less time, reducing the risk of the young hoggets developing resistance to the ingredient at this early stage of their life as capital stock."

A five-in-one vaccination is also recommended for hoggets when the autumn flush and winter crops can be high risk for pulpy kidney. A two dose course of a vaccination such as Pfizer's Ultravac is recommended before this high risk period begins.

"There has probably never been a season when investment in good treatment and management time yields a better return than this year," says Watson.

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