Starch levels on performance,milk composition and energy balance of lactating dairy cows

The objective of this experiment was to evaluate the effects of starch levels in diets with the replacement of citrus pulp for corn on milk yield, milk composition, and energy balance of lactating dairy cows. Twenty-eight multiparous Holstein cows were used in seven 4?×?4 Latin squares conducted concurrently, and each experimental period consisted of 20 days (16 days for adaptation and 4 days for sampling). The experimental treatments comprised four starch levels: 15, 20, 25, and 30 % in the diet. The dry matter intake increased linearly with increasing starch levels. The milk yield and 3.5 % fat-corrected milk yield showed quadratic response to increasing starch levels. The milk protein content and milk total solids content responded linearly to increasing starch levels. The feed efficiency, milk lactose content, milk urea nitrogen, plasma urea nitrogen, and plasma glucose concentration were not affected by starch levels. The estimated net energy for lactation (NE_L) intake increased linearly as the starch level was raised. Although the milk NE_L output per kilogram of milk was not affected by starch, the milk NE_L output daily responded quadratically to starch levels. In addition, the NE_L in body weight gain also responded quadratically to increasing starch levels. The efficiency of energy use for milk yield and the NE_L efficiency for production also responded quadratically to increasing starch levels. Diets for mid-lactating dairy cows producing around 30 kg/day of milk should be formulated to provide around 25 % starch to optimize performance.

     

Evaluation of external markers to estimate fecal excretion,intake, and digestibility in dairy cows

Tropical Animal Health and Production - The objective of this study was to compare the use of an external marker titanium dioxide (TiO2) as an alternative to chromic oxide (Cr2O3) in dairy cows....     

Effects of maternal dietary omega-3 polyunsaturated fatty acids and methionine during late gestation on fetal growth,DNA methylation,and mRNA relative expression of genes associated with the inflammatory response,lipid metabolism and DNA methylation in placenta and offspring's liver in sheep

Background:Omega-3 PUFA or methionine (Met) supply during gestation alters offspring physiology. However, the effect of both nutrients on fetal development has ...     

Maternal supply of methionine during late-pregnancy enhances rate of Holstein calf development in utero and postnatal growth to a greater extent than colostrum source

Background: Pregnancy and early life are critical periods of plasticity during which the fetus and neonate may be influenced by environmental factors such as nutrition.Maternal methionine(Met) supply in non-ruminants during pregnancy can affect offspring development and growth.Thus,the objective of this study was to investigate if increasing Met supply during late-pregnancy affects developmental parameters of the calf at birth and if either maternal Met or colostrum from Met-fed cows alters calf growth.Calves born to Holstein cows individually-fed a basal control [CON; 1.47 Mcal/kg dry matter(DM) and 15.3% crude protein] diet with no added Met or CON plus ethylcellulose rumen-protected Met(MET; Mepron? at 0.09% of diet DM; Evonik Nutrition Care GmbH,Germany)during the last 28 ± 2 d of pregnancy were used.A total of 39 calves were in CON(n = 22 bulls,17 heifers) and 42 in MET(n = 20 bulls,22 heifers).At birth,calves were randomly allocated considering dam treatment and colostrum as fol ows: 1) calves from CON cows and colostrum from CON cows(n = 21); 2) calves from CON cows and colostrum from MET cows(n = 18); 3) calves from MET cows and colostrum from MET cows(n = 22); and 4) calves from MET cows and colostrum from CON cows(n = 20).Al calves were housed,managed,and fed individual y during the first 9 wk of life.Results: Despite greater daily DM intake pre-partum in cows fed MET(15.7 vs.14.4 ± 0.12 kg/d,P 0.05),colostrum quality and quantity were not affected by maternal diet.At birth,MET calves had greater(P ≤ 0.05) body weight(BW,44.1 vs.42.1 ± 0.70 kg),hip height(HH,81.3 vs.79.6 ± 0.53 cm) and wither height(WH,77.8 vs.75.9 ± 0.47 cm).In contrast,concentrations of His,Lys,and Asn in plasma were lower(P ≤ 0.05) in MET calves.Regardless of colostrum source,the greater BW,HH,and WH in MET calves at birth persisted through 9 wk of age resulting in average responses of + 3.1 kg BW,+ 1.9 cm HH,and + 1.8 cm WH compared with CON.Average daily gain during the 9 wk was(P 0.05) 0.72 ± 0.02 kg/d in MET compared with 0.67 ± 0.02 kg/d in CON calves.Respiratory scores were normal and did not differ(P 0.05) due to maternal Met supply or colostrum source.However,fecal scores tended to be lower(P ≤ 0.10) in MET calves regardless of colostrum source.Conclusions: Increasing the maternal supply of MET during late-pregnancy enhanced growth in utero as wel as during the pre-weaning and early post-weaning periods.Although the ～ 1 kg/d greater DM intake during the last 2–3 wk prior to parturition could explain a portion of the 2 kg extra body mass of MET calves at birth,other mechanisms potential y encompassing nutrient assimilation efficiency likely played a role.Assessing the exact mechanisms sensitive to supply of Met or total amino acid supply during the latter stages of growth in utero merit further research.