PMID- 34016335
OWN - NLM
STAT- MEDLINE
DCOM- 20211203
LR  - 20211214
IS  - 0306-4565 (Print)
IS  - 0306-4565 (Linking)
VI  - 98
DP  - 2021 May
TI  - Long term genetic selection for reproductive success affects neonatal lamb 
      vitality across cold stress conditions.
PG  - 102908
LID - S0306-4565(21)00075-9 [pii]
LID - 10.1016/j.jtherbio.2021.102908 [doi]
AB  - Adverse weather conditions are important contributors to mortality in new-born 
      lambs. Previous studies have shown variation between lambs in their ability to 
      cope with circumstances of cold stress, and genetic selection could be a viable 
      option for improving animal robustness. The Elsenburg Merino flock was 
      divergently selected on number of lambs weaned (NLW). This resulted in divergent 
      responses in reproduction and lamb survival. This study evaluated lamb vitality 
      and mortality of positively selected H-Line relative to the negatively selected 
      L-Line in response to cold stress. Traits included lamb rectal temperature (RT), 
      surface temperature (ST), shiver score (SS), lamb vigor score (LVS), breaths per 
      minute (BPM), mortality to three days of age (M3) and to weaning (TM). Cold 
      stress was described by a chill index derived from daily rainfall, wind speed and 
      ambient temperature, and represented as the mean of the one (CI), two (CI-2) or 
      three (CI-3) days since parturition. Overall, H-Line lambs had a higher neonatal 
      RT and were less likely to succumb than L-Line contemporaries. In a significant 
      (P < 0.05) interaction, the predicted RT of L-Line showed a non-linear decline 
      with increased levels of CI-2, while H-Line lambs better maintained their core 
      temperature. M3 was also affected by a significant interaction between CI-3 and 
      selection line, further suggesting that observed lower mortality rates in the 
      H-Line depends on H-Line lambs' improved ability to cope with stressful 
      environments. Long term selection for NLW in the H-Line led to improvements in 
      both adaptations associated with lower lamb losses. The continued recording of 
      viability traits to produce larger datasets amenable to genetic analysis is 
      recommended, specifically for rectal temperature.
CI  - Copyright (c) 2021 Elsevier Ltd. All rights reserved.
FAU - Nel, Cornelius L
AU  - Nel CL
AD  - Department of Animal Sciences, Stellenbosch University, Stellenbosch, 7602, South 
      Africa. Electronic address: neliusn@elsenburg.com.
FAU - Cloete, Schalk W P
AU  - Cloete SWP
AD  - Department of Animal Sciences, Stellenbosch University, Stellenbosch, 7602, South 
      Africa. Electronic address: schalkc2@sun.ac.za.
FAU - Kruger, Annelie C M
AU  - Kruger ACM
AD  - Directorate: Animal Sciences, Western Cape Department of Agriculture, Elsenburg, 
      7607, South Africa. Electronic address: AnnelieK@elsenburg.com.
FAU - Dzama, Kennedy
AU  - Dzama K
AD  - Department of Animal Sciences, Stellenbosch University, Stellenbosch, 7602, South 
      Africa. Electronic address: kdzama@sun.ac.za.
LA  - eng
PT  - Journal Article
DEP - 20210317
PL  - England
TA  - J Therm Biol
JT  - Journal of thermal biology
JID - 7600115
SB  - IM
MH  - Animals
MH  - Animals, Newborn
MH  - Body Temperature
MH  - Cold-Shock Response/*genetics
MH  - Female
MH  - Male
MH  - Rain
MH  - Reproduction/*genetics
MH  - Selection, Genetic
MH  - Sheep/*genetics
MH  - Temperature
MH  - Wind
OTO - NOTNLM
OT  - Chill index
OT  - Heat loss
OT  - Lamb survival
OT  - Lamb viability
OT  - Selection
OT  - Sheep
EDAT- 2021/05/22 06:00
MHDA- 2021/12/15 06:00
CRDT- 2021/05/21 05:50
PHST- 2021/01/18 00:00 [received]
PHST- 2021/03/11 00:00 [revised]
PHST- 2021/03/11 00:00 [accepted]
PHST- 2021/05/21 05:50 [entrez]
PHST- 2021/05/22 06:00 [pubmed]
PHST- 2021/12/15 06:00 [medline]
AID - S0306-4565(21)00075-9 [pii]
AID - 10.1016/j.jtherbio.2021.102908 [doi]
PST - ppublish
SO  - J Therm Biol. 2021 May;98:102908. doi: 10.1016/j.jtherbio.2021.102908. Epub 2021 
      Mar 17.