The effects of high ambient temperature
and level of dietary heat increment on sow milk
production and piglet performance over a 28-d lactation
were determined in 59 multiparous crossbred Large
White × Landrace pigs kept at a thermoneutral (20°C)
or in a hot (29°C) constant ambient temperature.
Experimental
diets fed during lactation were a control diet
(NP; 17.6% CP) and two low-protein diets obtained by
reduction of CP level (LP; 14.2% CP) or both reduction
of CP and addition of fat (LPF; 15.2% CP); the NE:ME
ratio was 74.3, 75.6, and 75.8% for NP, LP, and LPF
diets, respectively. All diets provided 0.82 g of digestible
lysine/MJ of NE, and ratios between essential AA and
lysine were above recommendations. Creep feed was
provided after d 21 of lactation. Reduction of CP level
did not influence (P > 0.10) milk production, milk composition,
or piglet performance. Despite higher nursing
frequency (39 vs 34 sucklings per day), milk production
decreased (P < 0.01) from 10.43 to 7.35 kg/d when temperature
increased from 20 to 29°C.