Metabolic and endocrine profiles and hepatic gene expression in periparturient, grazing primiparous beef cows with different body reserves

Dietary restriction in sheep: Uterine functionality in ewes with different body reserves during early gestation

The aim of this study was to characterize insulin, leptin and IGF-1 profiles after undernutrition in pregnant ewes with different initial body condition (iBCS) and to investigate embryo quality, uterine gene expression and presence and location of proteins during early gestation (day 5). Thirty-six Rasa Aragonesa ewes were divided into 2 groups with different BCS: BCS> 2.75 (high, H, n = 19) and BCS <2.25 (low, L, n = 17) and they were randomly assigned to two nutritional treatments: 1.5 maintenance (M) (control, C) or 0.5 (M) (undernourishment, U) times the daily maintenance requirements establishing four groups: high-iBCS control (HC, n = 9), high-iBCS undernourished (HU, n = 10), low-iBCS control (LC, n = 9) and low-iBCS undernourished (LU, n = 8). High-iBCS ewes presented higher concentration of IGF-1, reflecting a better metabolic status in these animals. There was a greater proportion of high-iBCS ewes presenting more than one CL (P < 0.05), and associated greater P4 plasma concentration, number of recovered embryo and a tendency for higher embryo viability rate (P = 0.13). In uterus, undernourished ewes tended to present lower P4 (P = 0.09) and higher E2 concentration (P = 0.10). Inmunostaining of uterine progesterone and estrogen receptors (PR and ERα) was not affected by iBCS and nutritional treatment. Ewes with low-iBCS tended to have more INSR mRNA, and undernourished ewes tended to have more IGFBP2 mRNA expression (P < 0.08). An interesting finding was that the uterine response to undernutrition was dependent on iBCS: a higher expression of GHR (P < 0.05) and a tendency in IGFBP5 (P = 0.09) mRNA was found in undernourished than control ewes but only in the high-iBCS group. In summary, the present study demonstrates that the endocrine response and the uterine gene expression to undernutrition depend on the initial body energy reserves (iBCS) and appears to be associated with a differential embryo quality.

Performance and metabolic status of grazing beef heifers receiving increasing protein supplementation pre- and postpartum

The objective of the present study was to evaluate the effect of increasing levels of prepartum and postpartum protein supplementation on nutrient intake and digestibility, productive performance and metabolic status of beef heifers on tropical pasture. Twenty-eight pregnant beef heifers with bodyweight and body condition score of 459.7 ± 6.8 kg and 5.8 ± 0.10 respectively, were used. The experiment was performed according to a completely randomised design, with the following four treatments: 0.0, 0.4, 0.8 and 1.2 kg/animal.day of protein supplement containing 25% crude protein. All animals received a mineral mixture ad libitum. The experiment lasted 210 days, divided into three experimental periods. The supplementation level increased the intake of all evaluated nutrients, digestibility of organic matter, neutral detergent fibre corrected for ash and protein, as well as higher average daily gain prepartum and bodyweight of calves at birth (P &lt; 0.05). Protein supplement at the levels evaluated did not affect body condition score (P &gt; 0.05). An interaction effect between treatment × days in relation to calving occurred for concentrations of serum urea nitrogen, total proteins, albumin and globulins (P &lt; 0.05). Supplementation did not affect glucose, triglyceride, non-esterified fatty acids, β-hydroxybutyrate or progesterone (P &gt; 0.05). In conclusion, supply of up to 1.2 kg/day of protein supplement for grazing beef heifers optimises forage intake and average daily gain before calving, and improves the indicators of the protein status.

Effect of herbage allowance on productive and reproductive responses of primiparous beef cows grazing on Campos grassland

The effects of two levels of herbage allowance (HA, kg DM/kg liveweight (LW)) on forage mass and chemical composition, cow body condition score, cow LW, stocking rate, productive and reproductive responses were evaluated during two consecutive years. Eighty primiparous spring-calving beef cows were allocated to a completely randomised block design of two HA that had an annual average of 2.5 (low) and 4.0 kg DM/kg LW (high) from –150 to 195 days postpartum. The grazing system was continuous, and the put-and-take method was employed to adjust HA. At 86 ± 12 days postpartum, all cows were submitted to calf suckling restrictions with nose plates (12 days) and dietary flushing (2 kg/cow.day of whole-rice bran for 22 days), 6 days before bull introduction. Forage mass was affected by HA (P = 0.004) and year (P = 0.014); the high HA had a greater forage mass than the low HA (1474 vs 1212 ± 86 kg DM/ha; P < 0.05), and Year 2 had a greater forage mass than Year 1 (1545 vs 1134 ± 78 kg DM/ha; P < 0.05). Stocking rate was affected by HA and season (P = 0.0004) interaction. The stocking rate during autumn and spring was greater in low than high HA, and no differences were identified in winter and summer. The body condition score was improved in high HA during autumn and resulted in a greater winter (mid-gestation) body condition score than the low HA without differences during spring-summer (postpartum). Cow LW was lower during autumn, winter and early postpartum (16 days postpartum) in low HA in Year 1 than high HA of Year 1 and high and low HA cows in Year 2. Furthermore, the probability of total pregnancies (0.88 vs 0.59 ± 0.07; P = 0.01) and the calf weight adjusted to 205 days (194 vs 175 ± 16 kg; P < 0.05) were greater in high HA. Calf weight adjusted to 205 days (Year 1: 192 vs Year 2: 177 ± 16 kg; P < 0.05) and survival curves of postpartum anoestrus (P = 0.01) were affected by year but did not affect the probability of conception, early or total pregnancies. In conclusion, the reproductive and productive responses of primiparous beef cows grazing Campos grasslands were improved in high HA and could contribute to alleviating adverse climatic conditions effects.

Metabolic and endocrine profiles and hepatic gene expression of Holstein cows fed total mixed ration or pasture with different grazing strategies during early lactation

Background

In dairy mixed production systems, maximizing pasture intake and total mixed ration (TMR) supplementation are management tools used to increase dry matter and energy intake in early lactation. The objective was to evaluate metabolic and endocrine profiles and hepatic gene expression of Holstein cows fed either TMR ad libitum (without grazing) or diets combining TMR (50 % ad libitum DM intake) and pasture with different grazing strategies (6 h in one grazing session or 9 h in two grazing sessions) in early lactation. Pluriparous cows were grouped by calving date, blocked within group by body weight and body condition score (BCS) and randomly assigned to one of three feeding strategies from calving (day 0) to 60 days postpartum: control cows fed TMR ad libitum (G0; confined cows fed 100 % TMR without access to pasture), pasture grazing with 6 h of access in one session supplemented with 50 % TMR (G1), and 9 h of access in two sessions supplemented with 50 % TMR (G2).

Results

Net energy (NE), but not metabolizable protein (MP), demands for maintenance and/or milk increased in G2 when compared with G1 and G0 cows, respectively. However, NE and MP balances were lower in G1 and G2 than G0 cows. Cow BCS at +55 days was greater in G0 than G2 cows and probability of cows cycling during the first month was greater in G0 and G1 than G2 cows. During the postpartum period, non-esterified fatty acids were greater in G1 than G2 and G0 and β-hydroxybutyrate was greater in G1 and G2 than G0 cows. Plasma insulin was greater and insulin-like growth factor (IGF)-I tended to be greater in G0 than G2 cows, leptin was greater in G2 and G0 and adiponectin were greater in G2 cows. Hepatic expression of growth hormonereceptor-1A and IGF1 mRNA decreased while IGF binding proteins 1,2,4,5 and 6 (IGFBP) mRNA as well as mRNA expression of insulin, leptin (LEPRb) and adiponectin-2 receptors increased from pre to postpartum in all cows. However, only hepatic IGFBP6 and LEPRb mRNA were greater in G2 than G0 and G1 cows, respectively.

Conclusion

Metabolic-endocrine profiles of cows with different feeding strategies in early lactation reflected not only changes in milk energy output and energy balance but also in walking and grazing activity. Concentrations of insulin and IGF-I were increased in G0 cows whereas plasma adiponectin and both, insulin and leptin sensitivity were improved G2 cows. Increased NE demands in G2 cows when compared to G1 and G0 cows, implied a metabolic stress that impacted negatively on reproductive function.

Electronic supplementary material

The online version of this article (doi:10.1186/s13028-015-0163-6) contains supplementary material, which is available to authorized users.