Sunday, July 3, 2022

First steps important

A study on triplet lambs by Massey University PHD student Gabriella Gronqvist showed that quick suckling off their mothers improved lamb survival.

Gronqvist presented the results of her PhD study on ewe/lamb behaviour and triplet survival at the International Sheep Veterinary Congress in Rotorua.

“We found that lambs that did suck from their dam within five minutes of tagging were approximately three times more likely to survive to weaning than lambs that didn’t suck at all when we were observing them.”

Gronqvist said initial suckling has been linked to lamb and ewe bonding as well as to lamb survival. In her study 87.5% of lambs that sucked in the first five minutes of being released after tagging survived.

Her study also showed ewe body condition score (BCS) can alter the behaviour of the lambs and consequently could affect lamb survival. The results showed lambs born to ewes with a BCS of 2 were significantly faster to make contact with their dam compared with lambs born to ewes with a higher BCS.

“To our knowledge this relationship between ewe condition score and time for the lamb and the ewe to make contact hadn’t been recorded previously, so it’s unclear what this means,” Gronqvist said. “But we think possibly that lambs from ewes with a lower condition score might be more needy.”

Gronqvist said New Zealand lambing percentages had increased from 100% in 1990 to 130% in 2010, mostly due to more multiple births, but there was a correlation between the increase in multiple births and lamb mortality, with low lamb survival rates especially in triplets.

The aim of Gronqvist’s study was to investigate the effect of ewe and lamb behaviour on triplet survival. She looked at the maternal behaviour of the ewes, the behaviour of the lambs, the effects of ewe nutrition during pregnancy, and the effect of body condition score (BCS) on both ewe and lamb behaviour, and examined the relationship between all these factors on triplet lamb survival.

The study began with 119 mixed-age, triplet-bearing ewes with a range of BCS from 2 to 3.

The ewes were all managed as one flock until day 115 of pregnancy when the flock was split and put on two different feeding programmes for 22 days.

At lambing, the study observed only full sets of triplets. The lambs were all ear tagged within 12 hours of birth, then the litter was placed together on the ground and observed for five minutes.

“We found that lambs that did suck from their dam within five minutes of tagging were approximately three times more likely to survive to weaning than lambs that didn’t suck at all."

Gabriella Gronqvist

Massey University PHD student

The study recorded the number of high and low-pitched bleats emitted by the lambs and the time it took for each lamb to stand up after being released to make contact with the ewe, to successfully suck from the mother, and the time it took for each lamb to follow the ewe if she moved away.

The mothers were also recorded for the number of high and low bleats and given a maternal behaviour score, ranked according to the distance the ewe moved away while the lambs were being tagged.

Under the conditions of this study, BCS and nutrition had little impact on lamb and ewe behaviour and lamb survival, but lamb birth weight and sucking from the dam did increase chances of survival.

In regards to nutrition, neither of the feeding programmes put the ewes under any stress as all ewes gained weight during those 22 days.

“We found that the probability of survival to weaning increased by two times for every 1kg increase in birth weight.

“Hopefully as I progress with my PhD we will get a bit of a clearer picture of the relationship between ewe and lamb behaviour and lamb survival.”

More: Country-Wide

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