Effect of grape seed and skin supplement on milk yield and composition of dairy ewes

In the present study, we investigated the effect of grape seed and skin supplement (GSSS), on lactating dairy ewes’ production. Ten dairy pregnant ewes from northern Tunisia were allocated to two groups: control diet (C) and supplemented with 20 % (w/w) GSSS. The experiment lasted for 8 weeks and took place after 2 months of lambing. During the experiment, daily milk yield and milk composition were determined. Supplementation of the diet with GSSS increased milk production (P?<?0.001), calcium (P?<?0.01), free iron (P?<?0.01) and urea content (P?<?0.001) but had no effect on milk fat nor protein. From these data, it is concluded that the inclusion of GSSS in sheep diets increased significantly ewes’ milk yield.     

苜蓿青贮料替代苜蓿青干草对奶牛生产性能及乳品质的影响

试验旨在探讨苜蓿青贮料替代不同比例苜蓿青干草对奶牛生产性能、乳品质、营养物质表观消化率、血液生化指标及经济效益的影响。选取体重、产奶量、胎次相近的健康泌乳中期中高产中国荷斯坦奶牛15头,随机分为3组,每组5个重复,每个重复1头牛。对照组饲喂4.0 kg苜蓿青干草,试验A、B组分别用4.4,8.8 kg苜蓿青贮料代替2.0和4.0 kg等干物质的苜蓿青干草,正试期64 d。结果表明,1)各组间干物质采食量差异不显著(P>0.05),B组产奶量显著低于对照组(P<0.05),A组与对照组、B组间差异不显著(P>0.05); 2)用50%,100%的苜蓿青贮料替代等干物质的苜蓿青干草,其乳蛋白、乳脂率、乳糖均有所改善,但只有B组的乳脂率显著高于对照组(P<0.05),其余指标各组间差异均不显著(P>0.05);3)A、B组与对照组的中性洗涤纤维表观消化率、钙表观消化率无显著性差异(P>0.05),A、B组间粗蛋白和磷表观消化率差异不显著(P>0.05),但是粗蛋白表观消化率均显著低于对照组、磷表观消化率均显著高于对照组(P<0.05);4)苜蓿青贮料替代苜蓿青干草其血清总蛋白、白蛋白、血尿素氮、血糖、二氧化碳结合力等指标没有显著性改变(P>0.05);5)试验A、B组经济效益均有所增加,其中A组的净增收益最高,为0.61元/(头·d)。综上,用4.4 kg苜蓿青贮料代替2.0 kg苜蓿青干草对中高产奶牛是适宜的,能提高其生产性能,改善乳品质,增加收益。     

Milk yield, milk composition, eating behavior, and lamb performance of ewes fed diets containing soybean hulls replacing coastcross (Cynodon species) hay

The objective of this experiment was to evaluate the effects of replacing coastcross hay NDF by soybean hull (SH) NDF on the lactation performance and eating behavior of ewes and also on the performance of their lambs. Fifty-six Santa Inês lactating ewes (56.1 +/- 6.8 kg of initial BW; mean +/- SD) were penned individually and used in a randomized complete block design with 14 blocks and 4 treatments. Diets were formulated to provide similar concentrations of NDF (56%) and CP (16%). The SH NDF replaced 33 (SH33), 67 (SH67), or 100% (SH100) of the NDF contributed by coastcross hay in a 70% forage-based diet (SH0), resulting in SH inclusion rates of 0, 25, 54, and 85% of the dietary DM. Once a week, from the second to the eighth week of lactation (weaning time), ewes were separated from their lambs, stimulated by a 6-IU i.v. oxytocin injection, and hand milked to empty the udder. After 3 h, milk production was obtained after the same procedure. Quadratic effect for milk production (142.4, 179.8, 212.6, and 202.9 g/3 h) and cubic effect for DMI (2.27, 2.69, 3.25, and 3.00 kg/d) were observed as SH inclusion increased from 0 to 85% of the dietary DM. Milk fat (7.59, 7.86, 7.59, and 7.74%), protein (4.53, 4.43, 4.40, and 4.55%), and total solids (18.24, 18.54, 18.39, and 18.64%) did not differ among the 70% forage-based diet and diets with SH NDF replacing 33, 67, or 100% of the NDF. A linear increase in lactose concentration was observed with SH inclusion. Ewe BW gain during the trial showed a cubic response (0.37, 0.03, 4.80, and 2.80 kg) with SH inclusion. The preweaning ADG of lambs increased linearly, and ADG of lambs after weaning decreased linearly with SH inclusion. Final BW of lambs (2 wk after weaning) did not differ among treatments. Eating behavior observations were conducted with 44 ewes. The same facilities, experimental design, dietary treatments, and feeding management were used. Observations were visually recorded every 5 min for a 24-h period when ewes were 46 +/- 6.8 d in milk. Eating time (min/d, min/g of DMI, and min/g of NDF intake) and time expended in rumination and chewing activities (min/g of DMI and min/g of NDF intake) decreased linearly with the addition of SH in the diets. The inclusion of SH improved DMI and milk production, also reflecting on the BW of lambs at weaning. Milk performance was not affected when SH NDF replaced 100% of hay NDF.     

Effect of water restriction on milk yield and quality in Lacaune breed ewes

The effect of water restriction on body weight, body condition score, milk yield, and milk composition and rheological characteristics in intensively reared Lacaune ewes was evaluated. After 7 days of adaptation, the trial lasted 28 days. Thirty lactating ewes (48 ± 5 months of age; mean value ± standard deviation) at the beginning of third lactation month were divided into three groups (n = 10), corresponding to the following water restriction treatment: a group control received no drinking water restriction (W100), and two groups received water to the extent of 80% and 60% of W100 daily consumption (W80 and W60 group respectively). The effects of water restriction were assessed at the beginning of experiment (D0), at D14 and D28. The W60 group resulted in a significant decrease in body weight, body condition score, milk yield and feed consumption of hay due to the experimental treatment; whereas a marked increase in both W60 and W80 groups of milk lactose, urea, sodium, sodium chloride content and titratable acidity was observed. Rheological parameters of milk, rennet coagulation time and curd‐firming time were positively affected by water restriction treatments, with a decrease in both experimental groups of the time required for the formation of a stable and firm curd. Results highlight the importance of water consumption in dairy sheep. The scarce availability of water, significantly affecting ewes milk production, is worthy of particular attention in arid area where water stress‐resistant breeds should be considered. This study underlines that milk yield, being closely linked to the availability of water of the breeding habitat due to its high water content (about 81%), could be reached in area where water is not a limiting factor without reducing the genetic expression of the animals. Less severe water restrictions, such as 20% of daily voluntary water intake, produce no detrimental effect on milk yield.     

Effects of Ca salt supplementation on milk yield and composition and on lamb growth rate of Awassi ewes

An experiment was conducted to evaluate the effect of a Ca salt supplement on lactating Awassi ewes and their lambs. Ninety Awassi ewes (average BW = 55 kg ± 1.13) were allocated into three treatment groups of 30 each; 0%, 3%, or 5% Ca salt supplemented groups. The experiment started at lambing and lasted for 60 d. During this period, milk production and composition, final body weights, total feed intake, serum cholesterol and triglycerides, weaning weights of lambs, and milk fatty acid profile were tested. Milk production and energy corrected milk increased (P < 0.05) with Ca salt level in the diet. Milk fat content was higher (P < 0.05) at 3% treatment group compared to 0% and 5% treatment groups. However, no differences were detected in content of crude protein and total solids, and milk energy value. Milk fat yield (g/d) increased (P < 0.05) as Ca salt in the diet increased. Final body weight was higher (P < 0.05) for 5% group when compared to the 0% group with no differences between the 3% group when compared to 0% and 5% groups. No differences were observed in feed intake of ewes. Metabolizable energy intake was greater (P < 0.05) for the 3% and the 5% treatment groups when compared to the 0% treatment group. Feed to milk ratio increased (P < 0.05) when increasing the level of Ca salt in the diet. Serum cholesterol was greater (P < 0.05) in the 5% treatment group than the 0% and 3% treatment groups for ewes and lambs. Serum triglyceride was similar among treatment groups in ewes whereas serum triglyceride was greater (P < 0.05) for lambs in 5% treatment group than 0% and 3% treatment groups. However, serum triglyceride was similar in ewes among treatment groups. Weaning weights and average daily gain of male lambs were higher (P < 0.05) in lambs fed Ca salt (3% and 5%) when compared to 0% treatment group. No differences were detected in weaning weights and average daily gain of female lambs among treatment groups. However, milk conversion ratio was better (P < 0.05) for the 5% group lambs than the 0% and 3% treatment groups. Ca salt reduced (P < 0.05) short and medium-chain milk fatty acids and increased (P < 0.05) content of long chain and unsaturated ones. These results of this indicate that Ca salt supplementation can improve milk production of lactating ewes, the growth rate of their lambs, and produce healthy quality value milk.     

Effect of partly replacing cottonseed cake with Mucuna spp. (var. Ghana) hay on feed intake and digestibility, milk yield and milk composition of zebu cows

The effect of partly replacing cottonseed cake with Mucuna hay (Mucuna spp. var. Ghana) on feed intake, digestibility and milk production of dairy cows was studied using six Zebu cows randomly assigned to three dietary treatments in a replicated Latin square design. All cows were fed hay from natural pastures ad libitum and 1.1 kg molasses as a basal diet, which was supplemented with: (1) 2 kg cottonseed cake (control diet), (2) 1.5 kg cottonseed cake and 1.2 kg Mucuna hay (low Mucuna, LM), and (3) 1.0 kg cottonseed cake and 3.3 kg Mucuna hay (high Mucuna, HM). Dry matter (DM) and crude protein (CP) intake were similar for all the diets. The addition of Mucuna significantly increased DM and organic matter digestibility, whereas CP, acid detergent fibre and neutral detergent fibre digestibility were similar among the diets. The treatments had no effect on daily milk yield (3.38, 3.43 and 3.38 kg milk) or milk composition (41.1, 43.7 and 42.7 g fat/kg milk; 35.1, 36.4 and 35.9 g protein/kg milk; and 46.1, 45.8 and 45.3 g lactose/kg milk, respectively, for cows fed control, LM and HM diets). The treatments had no significant effect on live weight changes. The results showed that replacing 50% of the cottonseed cake with Mucuna hay had no negative effects on feed intake and digestibility, milk yield or milk composition.     

Effect of different levels of Quebracho tannin on nitrogen utilization and growth performance of Najdi sheep fed alfalfa (Medicago sativa) hay as a sole diet

A commercial tannin source (Quebracho tannin, QT), containing 75% condensed tannins (CT) in dry matter (DM) was used to evaluate the effects of addition of different levels of QT to alfalfa hay on the in vitro degradation kinetics of organic matter (OM) and nitrogen (N) in experiment 1 (Exp. 1), N utilization and microbial N synthesis (MNS) in experiment 2 (Exp. 2) and growth performance of growing Najdi lambs in experiment 3 (Exp. 3). Alfalfa hay was treated with QT at the levels of 0, 1, 2 and 3% of DM to form four treatments of QT0, QT1, QT2 and QT3 to have actual levels of CT being 0, 0.75, 1.5 and 2.25% of DM, respectively. Degradation rate and the effective degradability of N were significantly decreased ( P  < 0.05) for QT2 and QT3 as compared with the QT0. In Exp. 2, digestibility coefficients for OM, neutral detergent fiber and acid detergent fiber were significantly decreased ( P  < 0.05) at QT3, whereas QT1 and QT2 showed no difference toQT0. In the metabolism trial (Exp. 2), digested N (DN) and urinary N (UN) excretion for QT2 and QT3 were significantly decreased ( P  < 0.05) compared to QT0 and QT1. The DN and UN as percentage of N intake were 79.2, 76.9, 75.5 and 69.8%; and 24.4, 22.6, 19.9 and 19.6% for QT0, QT1, QT2 and QT3, respectively. QT2 had the highest MNS and the lowest value was in QT3, the MNS of the treatments were 18.1, 18.7, 19.2 and 15.8 g/day for QT0, QT1, QT2 and QT3, respectively. In the growth trial of 56 days duration (Exp. 3, n  = 24 lambs), the addition of QT at the level of QT2 enhanced ( P  < 0.05) the average daily gain and feed conversion rate compared with the QT0, while, QT1 and QT3 had intermediate values. It is concluded that alfalfa hay treated with QT at the level of 2% of DM could be used to protect alfalfa N from ruminal degradation that would lead to improve growth performance of lambs.     

Effects of total replacement of corn silage with sorghum silage on milk yield,composition, and quality

Background: In the last years, difficulties occurring in corn cultivation(i.e., groundwater shortages, mycotoxin contamination) have been forcing dairy farmers to consider alternative silages. Some experiments conducted on lactating cows have proven that the total replacement of corn silage with sorghum silage did not reduce milk yield.However, this kind of substitution involves supplementing sorghum-based diets with grains, to compensate for the lower starch content of sorghum silage compared to corn silage. Change of silage type and inclusion of starch sources in the diet would influence rumen fermentations, with possible effects on milk composition(i.e., fatty acid profile) and coagulation properties. A worsening of milk coagulation properties would have a negative economic impact in Italy, where most of the milk produced is processed into cheese.This study was designed to compare milk composition and quality, with emphasis on fatty acid profile and coagulation properties, in dairy cows fed two diets based on corn or sorghum silage.Results: The sorghum diet reduced milk yield(P = 0.043) but not 4% fat corrected milk(P = 0.85). Feeding sorghum silage did not influence milk contents of protein(P = 0.07) and lactose(P = 0.65), and increased fat content(P = 0.024).No differences emerged for milk concentrations of saturated(P = 0.61) and monounsaturated fatty acids(P = 0.50),whereas polyunsaturated fatty acids were lower(P 0.001) for the sorghum diet. Concentrations of n-6(P 0.001) and n-3 fatty acids(P = 0.017) were lower in milk of cows fed the sorghum diet. Milk coagulation properties did not differ between the two diets, except the "a30"(the curd firmness, expressed in mm, 30 min after rennet addition), that was lower(P = 0.042) for the sorghum diet.Conclusions: Feeding a forage sorghum silage, properly supplemented with corn meal, as total replacement of corn silage maintained milk composition and did not influence negatively milk coagulation properties, which have a great economic relevance for the Italian dairy industry. Thus, silages obtained from forage sorghums could have a potential as substitute of corn silages in dairy cow diets.     

Effect of bromelain on milk yield,milk composition and mammary health in dairy goats

A 7 month prospective cohort study was designed to determine if feeding bromelain to dairy goats influenced the MSCC, milk yield, milk composition and the incidence of IMI. Forty-four clinically normal goats from 2nd to 6th parities were studied. Daily bromelain dosage was 7.4 grams/animal (185-mg/Kg weight). Samples for diagnostic bacteriology were collected from each udder half every 2 weeks. Samples for MSCC and composition were obtained every 42 days. Milk yield was also recorded every 42 days. Bromelain affected milk protein and fat but not MSCC, milk yield or milk lactose. Bromelain did not decrease the MSCC in healthy goats. Milk protein and fat increased in the bromelain treated group (P < 0.01), which is important for dairymen because premiums are paid milk fat and protein content. No clinical mastitis was detected in the goats for the total study period and incidence rate of subclinical IMI was 5.7%. Relative risk was 1.50 (0.28 < RR < 8.12) which means that the bromelain had no significant effect on IMI (P > 0.05). In addition, the use of pineapple by-products could be especially important in tropical countries were pineapple waste seems to be a pollution problem.     

日粮添加植物油籽对奶牛产奶量、乳成分及采食量的影响

本试验选择40头生产性能、泌乳日龄相近的妊娠荷斯坦奶牛，采用单因素随机区组试验设计，研究添加不同植物油籽对其生产能力及乳成分等的影响。试验结果表明添加植物油籽对产奶量影响差异不显著，但是混合油籽和膨化大豆组较对照组的产奶量有提高的趋势；添加植物油籽对乳常规成分中乳脂、乳蛋白、总固形物之间的改变差异不显著；大豆的不同加工方式对产奶量也无显著影响；添加油籽并不影响奶牛对各营养成分的采食；添加植物油籽可以提高奶牛对外界恶劣环境的抵抗力。     

氨基酸在紫花苜蓿干草品质评定中的作用

试验旨在探究紫花苜蓿氨基酸在营养品质评定中的作用,以不同品种紫花苜蓿(皇后、WL319HQ和Bara310SC)为研究对象,测定并综合分析其产量(CL)、营养品质以及17种氨基酸含量.结果 显示:皇后的干草产量、粗脂肪含量显著高于WL319HQ和Bara310SC (P＜0.05);WL319HQ和Bara310SC的...     

Effect of supplemental yeast culture and physiological factors on colostrum and milk composition of Pelibuey ewes

The effects of supplemental yeast culture, litter size, stage and number of lactation on milk composition were studied in Pelibuey ewes. Twenty ewes were randomly assigned to one of two dietary treatments. Ten control ewes grazed on guinea grass (Panicum maximum) and were supplemented with concentrate. A further ten ewes received the same diet with 14 g/head/day of yeast culture (Saccharomyces cerevisiae). Colostrum was collected within 24 h after parturition, and subsequently, milk samples were collected at fortnightly intervals (7, 21, 35, and 49 days). Total solids content averaged 32% in colostrum and 12.5% in milk. Colostrum of primiparous ewes had higher total solids content than that of ewes with more than five lactations. However, ewes with more than five lactations produced milk with higher net energy, total solids, protein, and casein than ewes with fewer lactations. Milk at 7 days had a significantly higher content of energy, total solids, and fat than milk at 21, 35, and 49 days. Total solids content was lower for ewes rearing one lamb than larger litter sizes. Supplementation with yeast culture did not affect the composition of colostrum and milk, which was mainly affected by the stage and number of lactation.     

施磷对滴灌苜蓿干草产量及磷素含量的影响

为探讨不同施磷量对滴灌苜蓿干草产量、吸磷量及苜蓿磷素利用效率的影响,明确不同磷素水平下土壤全磷和速效磷的含量分布特征。试验设4种施磷梯度,分别为施P₂O₅ 0 kg·hm^-2(CK)、50 kg·hm^-2(P₁)、100 kg·hm^-2(P₂)、150 kg·hm^-2(P₃),采用滴灌水肥一体化施肥方式,平均分4次分别在返青后的分枝期、第1茬、第2茬、第3茬刈割后3~5 d施入。结果表明,各茬次苜蓿植株叶片、茎秆磷含量在P₂处理下达到最大值,其中叶片磷含量数值分别为0.223%,0.275%,0.292%和0.218%;茎秆磷含量数值分别为0.202%,0.223%,0.201%和0.146%。苜蓿叶片磷含量大于茎秆磷含量。滴灌苜蓿植株的干草产量、吸磷量随着施磷量的增加呈先增加后降低的趋势,在第1茬P₂处理达到最大值,数值分别为6.54 t·hm^-2和13.78 kg·hm^-2。土壤全磷含量、速效磷含量随着施磷量的增加呈逐渐增大的趋势,且各施磷处理显著大于未施磷处理(P<0.05),滴灌苜蓿总干草产量在P₂处理条件下达到最大,达21.24 t·hm^-2。苜蓿的磷素利用效率为随施磷量的增加呈逐渐降低的趋势,P₁处理苜蓿的磷素利用效率在第1茬达到最大值为28.37%。滴灌苜蓿植株吸磷量与干草产量呈极显著正相关(P<0.01)。当施P₂O₅为100 kg·hm^-2(P₂)时,能够有效促进苜蓿根系对土壤速效磷的吸收,提高苜蓿磷素利用效率,进而提高滴灌苜蓿干草产量。     

Effect of particle size and partial replacement of alfalfa hay by soya bean hulls on nutrient intake,total tract digestibility and rumen degradability of diets by Holstein steers

This study examined the effect of alfalfa hay (AH) particle size and the replacement of soya bean hull (SH) for AH within the diet of restricted fed Holstein steers on dry matter intake (DMI), total tract digestion, ruminal digestion, ruminal pH and ammonia nitrogen content, and faecal pH. Four rumen‐cannulated Holstein steers averaging 353 ± 9.6 kg of BW were assigned to a 4 × 4 Latin square experiment with four periods and a 2 × 2 factorial arrangement of treatments. Factor A was AH particle size (fine vs. coarse) and factor B was diet SH content (0% vs. 10%; substituted for AH). Steers were fed at 1% of body weight of TMR containing 400 g/kg forage and 600 g/kg concentrate. Chopping of AH to fine particles decreased (p = 0.01) amount of dietary materials retained on the medium sieve (8 mm). The inclusion of SH significantly increased (p = 0.01) materials retained on the 1.18‐mm sieve and tended to decrease (p = 0.07) materials on 19‐mm sieves. The inclusion of SH increased (p = 0.01) ether extract (EE) intake and increased (p = 0.07) DMI. Inclusion of SH increased (p = 0.01) EE digestion and decreased (p < 0.01) faecal pH. Neither AH particle size nor SH inclusion in diets affected (p > 0.10) the in situ ruminal degradability coefficients of DM (‘a’, ‘b’, ‘c’ or ‘a+b’). No interaction of AH×SH was seen on nutrient intake, digestibility and in situ ruminal degradability of Holstein steers.     

Nutritional plane and selenium supply during gestation affect yield and nutrient composition of colostrum and milk in primiparous ewes

The objectives were to investigate effects of nutritional plane and Se supply during gestation on yield and nutrient composition of colostrum and milk in first parity ewes. Rambouillet ewe lambs (n = 84, age = 240 ± 17 d, BW = 52.1 ± 6.2 kg) were allocated to 6 treatments in a 2 × 3 factorial array. Factors included Se [adequate Se (ASe, 11.5 μg/kg of BW) or high Se (HSe, 77.0 μg/kg of BW)] initiated at breeding, and nutritional plane [60 (RES), 100 (CON), or 140% (HIH) of requirements] initiated at d 40 of gestation. Ewes were fed individually from d 40, and lambs were removed at parturition. Colostrum was milked from all ewes at 3 h postpartum, and one-half of the ewes (n = 42) were transitioned to a common diet meeting lactation requirements and mechanically milked for 20 d. Colostrum yield was greater (P = 0.02) for HSe ewes than ASe, whereas CON had greater (P < 0.05) colostrum yield than RES and HIH. Colostrum Se (%) was greater (P < 0.01) for HSe than ASe. Colostrum from ewes fed HSe had less (P = 0.03) butterfat (%), but greater (P ≤ 0.05) total butterfat, solids-not-fat, lactose, protein, milk urea N, and Se than ASe. Colostrum from HIH ewes had greater (P ≤ 0.02) solids-not-fat (%) than RES, whereas RES had greater (P ≤ 0.04) butterfat (%) than CON and HIH. Colostrum from ewes fed the CON diet had greater (P = 0.01) total butterfat than HIH. Total solids-not-fat, lactose, and protein were greater (P < 0.05) in colostrum from CON than RES and HIH. Ewes fed HSe had greater (P < 0.01) milk yield (g/d and mL/d) than ASe, and CON and HIH had greater (P < 0.01) yield than RES. Milk protein (%) was greater (P ≤ 0.01) in RES compared with CON or HIH. Ewes fed HSe had greater (P < 0.01) milk Se (μg/g and mg/d) than ASe on each sampling day. Milk from CON and HIH ewes had greater (P < 0.01) total solids-not-fat, lactose, protein, and milk urea N than RES. Total Se was greater (P = 0.02) in milk from ewes fed the CON diet compared with RES. Somatic cell count and total somatic cells were greater (P ≤ 0.05) in milk from CON than RES. A cubic effect of day (P ≥ 0.01) was observed for milk yield (g and mL). Butterfat, solids-not-fat, lactose, milk urea N, and Se concentration responded quadratically (P ≤ 0.01) to day. Protein (%), total butterfat, and total Se, and somatic cells (cells/mL and cells/d) decreased linearly (P < 0.01) with day. Results indicate that gestational nutrition affects colostrum and milk yield and nutrient content, even when lactational nutrient requirements are met.     

生长调节剂对紫花苜蓿种子产量及产量构成要素的影响

以中苜2号紫花苜蓿Medicago sativa为研究对象,于2008年3-10月在内蒙古乌海市进行了生长调节剂对紫花苜蓿种子产量及牧草产量构成要素的影响研究。试验选择了乙烯利、多效唑和萘乙酸3种生长调节剂,每种生长调节剂设4个质量浓度梯度,采用随机区组设计,重复3次,研究结果表明：乙烯利、多效唑处理增加了紫花苜蓿单位面积花序数,单位面积结荚花序数和每花序荚果数。萘乙酸增加了平均种子单粒质量。乙烯利处理为2.0 kg/hm2时,获得潜在种子产量最大,为2 243.68 kg/hm2,增产72%;多效唑处理为0.8 kg/hm2时,获得的潜在种子产量最大,为1 675.71 kg/hm2,增产28.6%;萘乙酸处理为0.08 kg/hm2时,获得的平均种子单粒质量最大,为2.35 mg。     

不同粗饲料对奶牛乳产量和乳成分的影响

选择18头荷斯坦奶牛,设置3个处理,每个处理6个重复,每个重复1头奶牛,研究不同粗饲料对奶牛泌乳性能和乳成分的影响,3个处理的粗饲料分别为玉米秸(Ⅰ组)、玉米秸+青贮玉米秸(Ⅱ组)、羊草(Ⅲ组)。试验结果表明:①试验Ⅱ组与试验Ⅲ组平均产奶量差异不显著(P>0.05),试验全期分别比Ⅰ组提高了8.82%(P<0.05)和9.57%(P<0.05);②不同处理间的乳糖、乳脂含量差异不显著(P>0.05);对于乳蛋白,在试验40d时3个试验组差异不显著(P>0.05),在第15d时Ⅱ组、Ⅲ组分别比Ⅰ组降低了7.43%(P<0.05)和8.57%(P<0.05)。对于乳干物质,Ⅱ组与Ⅲ组差异不显著(P>0.05)。根据上述生产性能指标综合评定,玉米秸+青贮玉米秸可有效替代羊草饲喂奶牛,而不降低泌乳性能。