The treatment of ketosis with glycerol was first introduced in the 1950s. Currently, the availability of glycerol as a feed supplement for dairy cattle has increased due to the rapid expansion of the biodiesel industry. It has been suggested that glycerol can be used as a dietary glucose precursor for dairy cows in a similar way to propylene glycol. This study examined the effect of orally administrated crude glycerol on milk production and composition, and energy-status related blood metabolites of primiparous (n=4) and multiparous (n=4) Holstein dairy cows in the first three weeks of lactation. The treatment group cows were given an oral drench of 500 mL of crude glycerol once a day before the morning feeding. Long-term oral drenching of crude glycerol had no effect on dry matter intake (DMI), but there was a positive effect on milk yield. Most milk composition values were not affected by the treatment, but treatment groups had lower milk protein levels. Blood glucose and insulin concentrations were declined with glycerol administration.

The research was conducted in Latvia University of Agriculture Research and Study Farm ‘Vecauce’ in 600 dairy cows herd, in the period from 2009 to 2013. Within the framework of the research, growth indicators (from birth till the first delivery) of 102 dairy cow calves were analysed. Live weight and hip height of the heifers were found out at birth, at the age of 6 and 12 months, at first insemination and first calving. Heifers born to primiparous cows in both breed groups had notably lower live weight (42.0 and 42.4 kg), as compared to the 4th group heifers born to mature cows (p is less than 0.05). At the age of one year, the greatest weight among the red breed animals was recorded for the 4th group heifers born to mature cows (on average 354.8 ± 7.09 kg), while in Holstein breed those were heifers born to mothers calving on average for the 2nd time (on average 363.0 ± 6.47 kg). The 4th group heifers born to mature Holstein cows had notably greater hip height at birth – on average 78.1 ± 0.9 cm (p is less than 0.05). Heifers of red and Holstein breeds on average were inseminated at the age of 14.6 – 14.8 months as they reached live weight 395 – 396.5 kg. Heifers of red breeds on average calved at the age of 25.8 months, whereas Holstein heifers - of 26.4 months. The research aimed at analysing growth rates of heifers born to dairy cows at different age.

The goal of this study was to investigate the use of body reserves, energy balance and fertility parameters at the beginning of lactation in first-parity cows bred in Estonia.