Name: Impacts of feeding lipid supplements high in palmitic acid or stearic acid on performance of lactating dairy cows

Author: M.B. Chamberlain & E.J. DePeters

ABSTRACT: Effects of feeding lipid supplements high in free fatty acids (FAs) of palmitate (C16:0) or stearate (C18:0) plus C18:1 cis 9&10 on milk yield and composition, apparent whole-tract apparent digestibility of FA, and the FA composition of milk lipids were studied. Four lactating Holstein cows with ruminal cannulae were used in a 4 × ۴ Latin square assignment of four dietary treatments. Lipid supplements were enriched in free fatty concentrations of either palmitic acid (P) or stearic acid (S). The total mixed-ration contained 20 g/kg of lipid supplement that consisted of varying proportions of P to S. Treatments were: 100:0 P:S (P), 0:100 P:S (S), and two mixtures including 66:34 P:S (PS) and 34:66 P:S (SP). Milk yield and dry matter intake were not affected by lipid supplement, but the concentration and yield of fat in milk increased with increasing C16:0 in the lipid supplement. Increasing the C16:0 concentration in the lipid supplement increased its concentration in milk lipids while increasing C18:0 in the lipid supplement increased C18:0 concentration in milk fat. Whole-tract apparent digestibility of neutral detergent fiber (NDF) did not differ with lipid supplement, but organic matter digestibility tended to decrease with increasing C18:0 in the lipid supplement. Whole-tract digestibility of total FAs decreased with the increasing proportion of C18:0 to C16:0 in the lipid supplement. Apparent digestibility of C16:0 and C18:0 was not different within dietary treatment. The FA composition of the lipid supplement impacted both whole-tract digestibility of FAs and FA composition of milk lipids.

KEYWORDS: Fatty acids, palmitate, stearate, apparent digestibility, dairy cows

Download Full Text Effect of Breed, Parity, and Stage of Lactation on Conjugated Linoleic Acid (CLA) in Milk Fat from Dairy Cows_001

Name: The Effect of Breed, Parity, and Stage of Lactation on Conjugated Linoleic Acid (CLA) in Milk Fat from Dairy Cows

Auther: J.A.Kelsey*2B.A.Corl*R.J.Collier†D.E.Bauman*

Addresses:*Department of Animal Science, Cornell University, Ithaca, NY 14853
†Department of Animal Science, University of Arizona, Tucson, AZ 85721

Abstract: Dairy products are the main source of conjugated linoleic acid (CLA), a functional food component with health benefits. The major source of cis-9, trans-11 CLA in milk fat is endogenous synthesis via Δ۹-desaturase from trans-11 18:1, with the remainder from incomplete rumen biohydrogenation of linoleic acid. Diet has a major influence on milk fat CLA; however, effects of physiological factors have received little attention. Our objectives were to examine milk fat content of CLA and the CLA-desaturase index with regard to: 1) effect of breed, parity, and stage of lactation, and 2) variation among individuals and the relationship to milk and milk fat. Holstein (n = 113) and Brown Swiss (n = 106) cows were fed a single diet and milk sampled on the same day to avoid confounding effects of diet and season. Frequency distributions demonstrated that milk fat content of CLA and CLA-desaturase index varied over threefold among individuals, and this needs to be considered in the design of experiments. Holsteins had a higher milk fat content of CLA and CLA-desaturase index, but breed differences were minor. Parity and days in milk also had little or no relationship to the individual variation for these two CLA variables. Breed, parity, and days in milk accounted for <0.1, <0.3, and <2.0% of total variation in CLA concentration in milk fat, respectively. Milk fat content of CLA and CLA-desaturase index were essentially independent of milk yield, milk fat percent, and milk fat yield. We speculate that the basis for the genetic variation among individuals is related to rumen output of trans-11 18:1 and to a lesser extent cis-9, trans-11 CLA, and to the tissue amount and activity of Δ۹-desaturase.

Key words: breed, conjugated linoleic acid, desaturase index, milk fat

Download Full Text Dairy Cows With “Leftovers” and the Variation in Recovery of Human-Edible Nutrients in Milk

Name: Feeding Dairy Cows With “Leftovers” and the Variation in Recovery of Human-Edible Nutrients in Milk

Auther: Caio S. Takiya1, Caroline M. Ylioja1, Amanda Bennett1, Melissa J. Davidson1, Maggie Sudbeck1, Tryon A. Wickersham2, Michael J. VandeHaar3 and Barry J. Bradford1*

Addresses: ۱Department of Animal Sciences and Industry, Kansas State University, Manhattan, KS, United States
۲Department of Animal Science, Texas A&M University, College Station, TX, United States
۳Department of Animal Science, Michigan State University, East Lansing, MI, United States

Abstract: Ruminants can convert feeds unsuitable and unpalatable for humans into milk and meat, and thereby play a key role in food security. Milk production efficiency is usually calculated as the ratio between nutrients secreted in milk and nutrient intake, but this metric does not address concerns about human/livestock feed competition. Our objective was to evaluate effects of diets composed of ecological leftovers (ECO; industrial by-products and feed produced on land unsuitable for human food production) on dairy cattle productivity compared with traditional diets used in the U.S. We also sought to estimate human-edible (HE) nutrient recovery rate (HE inputs vs. milk nutrients) in different scenarios: thrift (all potentially HE ingredients counted as such), choice (ingredients rarely consumed by humans considered not HE), and land use (land used for forage production could be used to grow corn and soybeans for direct human consumption). Experiment 1 evaluated effects of an ECO diet (ECO1), incorporating wheat straw and by-products, on performance of 12 mid-lactation cows in a crossover design with 20-d periods. Experiment 2 evaluated effects of a different ECO diet (ECO2), using winter crop forage and by-products with or without rumen-protected Lys and Met (ECO2-AA), on performance of 12 late-lactation cows in a 3 × ۳ Latin square design with 21-d periods. Both ECO diets were compared to lactation diets typical in North America (CON). Although ECO1 decreased feed efficiency (milk yield ÷ feed intake), both feed intake and milk yield were maintained for primiparous cows. ECO1 increased the HE recovery of metabolizable energy (ME) and protein relative to CON1 across all food system scenarios. In Experiment 2, ECO diets significantly decreased feed intake and milk yield, and in the thrift scenario, recovery of ME and protein were worsened by ECO2. All diets resulted in a positive net recovery of HE digestible essential amino acids, and ECO diets further improved their recovery. In conclusion, several factors affect recovery of HE nutrients fed to dairy cows, including dietary composition, land use, and human food system assumptions. Depending on these factors, ECO diets can either improve or reduce the efficiency of converting HE nutrients from feeds into milk.

Keyword :arable land, by-product, feed efficiency, net food production, sustainability

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Name: Multifunctional slow-release urea fertilizer from ethylcellulose and superabsorbent coated formulations

Auther: BoliNi, MingzhuLiu, ShaoyuLü

Address: Department of Chemistry and State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, People’s Republic of China

Abstract: The aim of this study was to prepare a double-coated, slow-release, and water-retention urea fertilizer (DSWU) to reduce environment pollution derived from excessive nitrogen fertilizer use. Ethylcellulose (EC) and crosslinked poly(acrylic acid-co-acrylamide) (P(AA-co-AM)) were used as inner and outer coating materials, respectively. The structural and chemical characteristics of the product, as well as its efficiency in slowing the nitrogen release and water evaporation in soil were examined. The nitrogen content of the product was 21.1% and its water absorbency was 70 times its own weight in tap water. Additionally, the biodegradation of EC coating in soil was assessed by differential scanning calorimetry (DSC) measurements. The results showed that the glass transition temperature (Tg) of EC coating decreased with the time prolonged, which indicated the biodegradability of EC coating in soil. These studies showed that the product with good slow-release and water-retention properties, being environmentally friendly, would find good application in agriculture and horticulture.

Key Words: : Urea fertilizer, Ethylcellulose, Slow-release, Water-retention, Biodegradation

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دستورالعمل نیاز چربی برای گاوهای شیری در تعادل انرژی-نیکو رشد پایا

برای اکثر گونه های دیگر هیچ دستورالعمل قطعی در مورد مفیدترین سطح چربی برای گنجاندن در جیره وجود ندارد. با این حال، نیازهای چربی برای گاوهای شیری به طور گسترده مورد تحقیق قرار گرفته است و “قوانین کلی” برای تعیین کفایت چربی در جیره برای سطوح خاص تولید ایجاد شده است.
به خوبی ثابت شده است که سطح بهینه چربی در یک جیره برای حداکثر بازده تولید شیر زمانی رخ می دهد که ۱۵ تا ۲۰ درصد ME در جیره از چربی باشد. برای گاوهای پرتولید، این می تواند معادل حدود ۶ تا ۸ درصد ماده خشک جیره باشد.
یک رویکرد دیگر، ایجاد تعادل بین چربی مصرف شده در خوراک و تولید چربی در شیر در روز است (Palmquist و Eastridge, 1991). یک تقریب خوب برای گاوها در تعادل انرژی (عدم به دست آوردن یا از دست دادن وضعیت بدن) تغذیه به همان میزان چربی است که در شیر ترشح می شود – مثال را در جدول ۱ ببینید.

توصیه: جیره دام را با اضافه کردن ۵۰۰ گرم چربی محافظت شده در شکمبه تکمیل کنید تا کمبود را جبران کنید.