Nutritional factor




Gluconeogenic feed additives

Propylene glycol (PGL)


Despite evidence of improved metabolic status, PGL failed to increase LH pulse frequency, and failed to increase the proportion of first postpartum follicle waves resulting in ovulation


Reduced interval from calving to first ovulation was observed and pulsatile release of LH at 2 and 5 weeks was greater in cows fed PGL


Cows fed PGL commenced ovarian cyclicity earlier than controls


Improved conception rate (33 to 57%) and day of first ovulation from 44.5 Day to 32.3 Day

PGL + Ca-propionate


Treatment did not change the proportion of puerperal diseases and reproductive performance



No effect on DMI, glucose ↑, NEFA and BHB ↓


Conception rate and insulin cc. ↑

Propionate salts


Improves reproductive efficiency

Fat supplementation

Ca-long chain fatty acid (LCFA)


Pregnancy rate per AI increased from 35.5% to 51.1%

Fish oil


Reduced PGFM

Ca-LCFA of palm oil


From cows fed 800 g fat/day a higher percentage of oocytes developed into blastocysts

Soybean oil refining by-products (SORB)


Loss of body condition was less and first ovulation was experienced earlier in cows fed SORB

Saturated fatty acid (FA),

Ca-salts of t-octadecanoic FA,

Ca-salts of safflower oil FA


Mean concentrations of glucose, IGF-1 and P4 were higher in cows fed a safflower oil enriched diet

Ca salts of palm oil, Ca salts of safflower oil (SO) and fish oil (FO)


Overall pregnancy rate per AI was higher in cows fed an SO diet and pregnancy loss was reduced in FO-fed cows