The effect of feeding with protected fats on double

purpose cows. The objective of this study was to determine

the reduction of post-partum anestrum in cows by supplying

protected fats. The study was conducted ad the Experimental

fi eld La Posta, Paso del Toro, Veracruz, México. The cows

were randomnly assigned to two groups: suplementation

with protected fats (GP; T1, n= 20) or tallow (SGP; T2,

n=20) at 2.7% of a dry weight-based diet. Milk production,

physical condition (CC), progesterone and tiroid hormone

levels were registered. (T3 and T4). Sources of variation

were diet, genetic group and number of calf births, and the

dependent variables PL were days to the fi rst estrus (DPE),

CC and meatabolite levels. Correlations among variables

were conducted. No effect (p>0,05) of treatments on milk

production were observed, but signifi cant effects (p<0,01) for

the fi st corpus luteum. Physical condition 4,5 had the best milk

production (p<0,01; 16,68±1,076 L/day) and lower number of

days to the fi rst estrum (p<0,05; 31,71±7,5 d). Tiroid hormones

did not show differences (p>0,05) among treatments: T1= 72,4

and T2 = 72,72 ug/dl. Insuline was higher (p<0,05) in T2 (6,87

UI) than in T1 (5,26 UI). It is concluded that the type of fat

did not affect milk production but stimulated the resumption

of ovarian activity and reduced the concentration of insulin in

the serum.

Keywords: Fatty acids, ovarian activity, Insulin.