Effects of Inert Fat on Energy Balance, Plasma Concentrations of Hormones, and Reproduction in Dairy Cows

Abstract

The objective was to determine the effects of dietary inert fat on estimated energy balance, hormones in plasma, and reproduction during early lactation. From wk 0 to 12 postpartum, 14 pluriparous Holstein cows were fed individually a TMR, and blood samples were taken twice weekly for quantification of IGF-I, progesterone, and cholesterol. During wk 5 to 12, one-half of the cows remained on the TMR, and the other half were fed the TMR containing inert fat at 1.8% of dietary DM. Estrous behavior was monitored twice daily, and body condition scores were recorded every 4 wk. Cows fed inert fat between wk 5 and 12 postpartum had similar concentrations of IGF-I in plasma but greater luteal phase progesterone secretions than cows fed the control diet. Total cholesterol in plasma also was greater in cows fed inert fat than in cows fed the control diet. Intervals to first, second, and third ovulation or estrus did not differ among cows fed control or inert fat diets. Body condition scores, daily DMI, and milk production were not affected by dietary inert fat. Inert fat fed to cows between wk 5 and 12 postpartum did not affect ovulatory activity but may enhance luteal activity.

Alleviating Heat Stress Leads to Improved Cow Reproductive Performance

“…The negative energy balance is directly related to the postpartum interval to first ovulation, and follicle size was adversely affected by negative energy balance in early postpartum dairy cows [9]. The average EB during the first 4 week of lactation was negatively correlated to the postpartum interval to first ovulation [57]. …”

Effect of dietary energy source on energy balance, production, metabolic disorders and reproduction in lactating dairy cattle

“…In general, the negative effect of extra lipogenic sources on dry matter intake is higher when the degree of saturation of fatty acids is lower, probably because of the more pronounced negative effects of unsaturated fatty acids on rumen carbohydrate fermentation. As a result, 73% of the studies on feeding extra lipogenic nutrients [15,61,63,65,75,100,101,104,106] and also 73% of the studies on increasing dietary glycogenic nutrients [61,[69][70][71][72]117] obtained a higher net energy (NE) intake in the treatment group compared to the control group, illustrated by Figure 4 shows an overview of studies that reported milk yield and composition after feeding either more glycogenic nutrients or lipogenic nutrients. Both feeding extra lipogenic nutrients or glycogenic nutrients had similar effects on kg of milk produced per day [8, 15, 60-72, 75, 77, 78, 82, 99-104, 106, 107, 110, 111, 115-122] …”

“…Figure 5 further supports these hypotheses, by presenting 18 studies on either feeding more lipogenic or glycogenic nutrients on the calculated EB. Eight of the 12 studies reported an increase in EB after feeding extra lipogenic nutrients [8, 9, 12, 15, 64,66,106]. In contrast to feeding extra glycogenic nutrients where 12 out of 13 studies were able to improve, not-significantly, the calculated EB [66,69,71,72,77,107,108,110,112,116,120].…”

Relationship between Days to Postpartum First Ovulation and Days to Reaching Steady Range of Metabolite Concentrations in Dairy Cows

“…Although cholesterol is a precursor of steroids, the concentration of total cholesterol, without contrast between free cholesterol and cholesterol ester, has been investigated for the relationship with the interval to 1st-OV in early postpartum dairy cows [15,16]. In our results, there was a significant correlation between the interval to the 1st-OV and the mean free cholesterol in the pre-OV period, indicating that the free cholesterol concentration in this period might be the factor restricting steroidgenesis in both the adrenal cortex [11] and ovaries [17,18].…”