Reproductive and Maternal Behavior of Livestock - Genetics and the Behavior of Domestic Animals - page 171

exhibited the poorest mothering ability of those breeds compared, whereas
crossbred sheep were best. Merino dams were the most apt to abandon
lambs, although Romneys showed the poorest ability to seek shelter when
lambing in poor weather. Alexander et al. (1983) reported poor maternal
behavior in twin-bearing Merino, Dorset Horn and Border Leicester ewes in
Australia. Romanov ewes, on the other hand, are known for their shy behav-
ior as reflected by the weak level of exploration and superior maternal abili-
ties ( Boissy et al., 2005 ). A recent multibreed sheep study in Brazil found
that polymorphism (genotype AA or AB) in the aromatase gene (Cyp 19)
affects growth, reproduction and maternal ability. Genotype frequencies are
0.64 AB and 0.36 BB and ewes with genotype AB exhibited higher maternal
abilities, defined by lamb birth weight, weight gain and weaning weight
( L ˆ bo et al., 2009 ). Furthermore, breed differences in the expression of
maternal care at parturition persist throughout the lactation period with
Blackface sheep being more vigilant and Suffolk sheep allowing more suck-
ing bouts than the former ( Pickup and Dwyer, 2011 ).
Significant differences in maternal behavior have been observed between
two sheep breeds, i.e. Scottish Blackface and Suffolk. Here, Scottish
Blackface ewes were more vigilant, groomed their lambs more, stayed in
closer proximity to them and underwent longer sucking bouts than did Suffolk
ewes ( Pickup and Dyer, 2011 ). Nordic ewes remained closer to their lamb
when it was tagged compared with Karakas or Ile de France

Ahkarinen
ewes ( Yilmaz et al., 2011 ). A recent study in Scottish Suffolk sheep found
that birth difficulty and lamb vigor are moderately heritable, a finding which
might help increase lamb health and welfare if included in breeding programs
( Macfarlane et al., 2010 ). However, the heritability of rearing ability in ewes
is rather low and has not been confirmed ( Hatcher et al., 2010; Haughey,
1984; Piper et al., 1982 ) perhaps because the lamb also plays an active role in
establishing the maternal bond ( Nowak, 1989 ). Also, the quantification of
maternal behavior in sheep presents particular logistic problems as expression
of this trait may be influenced by parity, number of lambs, experience,
nutrition, and environmental factors ( Poindron and Le Neindre, 1980 ).
Temperament of both lamb and ewe can also play a role. For example, Plush
et al. (2011) found a genetic relationship between agitation scores of lambs
separated from their mothers and lamb survival, and Rech et al. (2008)
observed that more reactive or nervous ewes exhibited lower maternal care
and weaned less heavy lambs than did less reactive ewes.

3

Maternal Behavior in Goats
Gestation length in goats is variable and depends on the breed of the dam,
parity and season, with shortest length in summer and longest gestations in
winter ( Hoque et al., 2002 ). Granadina goats tend to have shorter gestation
than those of the Toggenburg and Alpine breeds. In general, prolonged