Influence of breed, number of suckling lambs, and stage of lactation on ewe milk production and lamb growth under range conditions

Milk production and lamb growth were characterized in 118 multiparous, 3- to 7-yr-old Rambouillet, Columbia, Polypay, and Suffolk ewes under spring sage range and high mountain meadow grazing from 28 to 98 d postpartum. Daily milk yield as measured by the lamb suckling weight differential technique did not differ (P greater than .05) among breeds, although milk production of Suffolk ewes tended to be higher than that of the other three breeds. Within the Rambouillet, Columbia, and Polypay breeds, total estimated yield of ewes with twins was 13 to 17% higher than that of ewes with singles, whereas in the Suffolk breed, suckling twins increased total milk yield 61% over that of ewes with singles. Twin lambs induced a larger differential in dam milk production in late lactation (70 to 98 d) than in earlier lactation (28 to 70 d). Number of lambs did not influence milk protein, Ca, or P content (P greater than .05). Fat levels in colostrum and 4-d milk were elevated 14 and 20%, respectively, in ewes suckling twins compared with ewes suckling singles. Under range conditions, Suffolk ewes suckling single or twin lambs lost more BW (12 and 21% of 4-d postpartum body weight, respectively) than Rambouillet (4 and 7%), Columbia (5 and 8%), or Polypay (8 and 8%) ewes. Correlation coefficients of milk production and lamb growth rate were positive and significant (P less than .05) up to 56 d of age. Growth rate was less closely associated with milk production for twin than for single lambs.     

The influence of breed and parity on milk yield, and milk yield acceleration curves

This study had two aims. Firstly, we wanted to quantify the effects of breed and parity on lactation curves. A parametric model for describing milk yield for cows [Friggens, N., Emmans, G., Veerkamp, R., 1999. On the use of simple ratios between lactation curve coefficients to describe parity effects on milk production. Livest. Prod. Sci. 62, 1–13] was used. The data contained 155,051 daily records of milk yield from 318 cows of three different breeds; Danish Red, Danish Holstein and Jersey. There were 276, 230, and 98 lactation curves for parities 1, 2 and 3 respectively. For every cow lactation, the parameters of the model were estimated using a least squares procedure for non-linear models. The resulting parameters were analysed in a mixed linear model. Significant effects of parity were observed on the same two parameters as in Friggens et al. [Friggens, N., Emmans, G., Veerkamp, R., 1999. On the use of simple ratios between lactation curve coefficients to describe parity effects on milk production. Livest. Prod. Sci. 62, 1–13]. Breed was also found to have a significant effect on some of the parameters. However, there was no significant interaction between breed and parity. The second aim of the study was to evaluate the properties of acceleration in milk yield in the context of providing an indicator for physiological stress and subsequent health problems. Milk yield acceleration was highest around calving and also reflected trends for higher stress/risk for higher yielding cows.     

The effect of breed, stage of lactation and parity on sheep milk fat CLA content under the same feeding practices

The cis-9, trans-11 C_18:2 (CLA) content in milk fat of four pure sheep breeds (Awassi, Lacaune, Friesland and Chios) was examined. All sheep were kept indoors all year round under the same feeding practices, without any grazing at all. Sheep nutrition was based on alfalfa hay and concentrates. A total of 237 individual milk samples were collected at three sampling times (December, January and March) from sheep of different parity and different days in milk, for CLA determination. The results showed that: (a) there was a large variation in milk fat CLA content among individuals consuming the same diet, (b) the CLA content of milk fat was lower in Friesland breed, compared to the other three breeds but without any significant difference among the four sheep breeds, (c) the CLA content of milk fat was not affected by ewes parity or days in milk, (d) there was a negative but not significant correlation between milk fat and CLA concentration, (e) the CLA content of milk fat was not correlated with milk yield. In conclusion, no others factors, such as breed, parity, days in milk, etc., can affect CLA content in milk fat, which means that the dietary ones remain the sovereign factors explaining the highest proportion of CLA content variability in sheep milk fat.     

胎次和热应激程度对广州地区奶牛产奶量和乳成分的影响

为了探究不同胎次和热应激程度对奶牛产奶量、乳脂率、乳蛋白率、脂蛋比、体细胞数和高峰奶量的影响,收集了广州某奶牛场360头荷斯坦泌乳母牛近5年的奶牛生产性能测定体系(DHI)数据,用R (Version 3. 3. 2)和SPSS 20. 0软件分析了不同胎次和热应激程度对产奶量及乳成分的影响。结果:相比于其他胎次的奶牛,头胎母牛产奶量、高峰奶量较低(P<0. 05);头胎牛的脂蛋比显著高于其他胎次牛(P<0. 05),其余各胎次间差异不显著(P>0. 05);随着胎次的增加,牛奶中体细胞数存在明显的上升趋势(P<0. 05)。中度热应激下的产奶量、高峰奶量显著低于轻度热应激(P<0. 05);中度热应激下产犊的奶牛体细胞数会稍稍偏高,但与无热应激和轻度热应激下产犊的奶牛相比差异不显著(P>0. 05);乳脂率、乳蛋白率各组差异不显著(P>0. 05)。     

Effect of lactation stage, season and parity on milk cortisol concentration in Holstein cows

This experiment was designed (1) to study the effects of lactation stage, season, and parity on milk cortisol concentrations in Holstein cows, and (2) to elucidate the relationships between milk yield, quality, and milk cortisol concentration. Subjects of this study were 24 dairy cows kept in a free stall barn. Milk samples were taken on test day in May, August, November, and February. Data of milk yield, quality, and cortisol concentration were collected. Random effects of animals and fixed effects of lactation stage, test day, and parity on milk yield, quality, and cortisol concentration were analyzed using mixed models. We estimated the best linear unbiased prediction of each trait (BLUP) which was an animal-specific value. Correlation among milk yield, quality, and cortisol concentration was calculated using raw data and BLUP. The effect of the lactation stage on milk cortisol concentration was significant: the value observed in early lactation was higher than in other stages. However, the correlation between milk yield and cortisol concentration was low. The beginning of lactation might be a strong stressor for every cow. Calculated with raw data, milk cortisol concentration had respectively significant negative correlation with milk protein contents and solid not-fat contents. Calculated with BLUP, milk cortisol concentration showed a significant and negative correlation with milk protein contents. The lactation stage and milk protein contents should be considered for measurement of milk cortisol concentrations.     

Influence of breed,parity, and stage of lactation on lactational performance and relationship between body fatness and live weight

The aim of this study was to characterise the effects of genotype, parity and nutrition on performance and the relationship between body condition and body weight. A total of 657 lactations from 322 cows were used. Three breeds were used, Danish Holstein, Danish Red and Jersey. Each breed was subdivided into two lines selected to differ in milk yield. Within line cows were randomly assigned to either a normal or low energy density total mixed ration. Three 1-week periods representing early lactation, peak milk yield and late lactation were identified for the analyses. For the analysis of the relationship between body weight and condition score, the dry period was also considered. There were significant effects of breed on all performance measures but no effect of line (with the exception of condition score). Cows fed the normal energy density diet had higher milk yield, fat percentage and condition score and weighed more than cows on the low feeding treatment. There was a highly significant relationship between body weight and condition score. In all periods except the dry period, there were significant effects of breed (P<0.001) and parity (P<0.05) on the intercept of the relation between body weight and condition score. However, there was no significant effect of breed or parity on the slope of the relationship between body weight and condition score.     

Effects of parity, breed, herd-year, age, and month of kidding on the milk yield and composition of dairy goats in Belgium

SUMMARY: Lactation records, collected from 1989 to 1995, for Belgian dairy goats were examined for effects of parity, breed, herd-year, age at kidding, and month of kidding on milk, fat and protein yields, and on fat and protein percentages. Total lactation yields were computed from test-day yields, using Fleischmann's method. For lactations longer than 250 days, yields were truncated at 250 days. Partial lactations (25 days minimum) were extended to 250 days, and fat and protein percentages were deducted from the yields. After editing a total of 2997 lactation records of 2562 does remained. The parity classifications were first and second or greater; kidding seasons were defined as December, January, February, March, April to July, and August to November. The breed groups were Anglo-Nubian, Chamoisee, Saanen, and crossbreeds. The data were analysed within parity with a fixed-effect model that included effects of herd-year, breed, month of kidding, and age at Kidding. All effects in the model were significant on the traits measured for parities, except the age effects on fat percentage and of month of kidding on protein percentage at first parity. Saanen had the highest milk yield at first parity; at later parities, the Chamoisee produced most. Yield increases were large between first and later parities. Does freshening in February produced more milk than those that freshened at other months. Monthly variations in fat and protein percentages across parities, although mostly significant, were small. Yields increased with age at first parity; for later parities, they increased until 25-30 months for milk and until 40 months for fat and protein, and then decreased. Fat and protein percentages increased up to 15-17 months of age, and then decreased to the lowest values around 25 months; this was followed by an increase around 32 months, which tended to stabilize until 50 months. The ranges of R(2) associated with effects were: for herd-year, 43-52% and 22-36%; for breed, 3-11% and 4-12%; for month of kidding 6-10% and 2-5%; for age at kidding 3-7% and 1-17%-for first and second, and later parities, respectively. RéSUMé: L'influence des effets numéro de lactation, race, troupeau-année, mois et age à la mise bas a été étudiée sur la production des chèvres laitières de Belgique, enregistrées de 1989 à 1995. Les productions totales réalisées ont été calculées à partir des résultats aux contr?les. Pour les lactations supérieures à 250 j, les productions ont été tronquées à 250 j. Les lactations partielles (minimum 25 j) ont été extrapolées à 250 j. Au total, 2997 lactations à 250 jours étaient disponibles, pour 2562 chèvres des races Anglo-nubienne, Chamoisée, Saanen et croisées. Les données ont été réparties en 2 parités (1 et ≥ 2), 6 mois de mise bas (décembre, janvier, février, mars, avril à juillet et ao?t à novembre). Le modèle d'analyse intra-parité comprenait les effets fixes troupeau-année, race, mois et age à la mise bas. Tous les effets ont été significatifs sur les paramètres étudiès à l'exception de l'effet de l'age sur les taux de matière grasse et de l'effet du mois de mise bas sur les taux de protéine, en parité 1. En première lactation, les Saanen ont enregistré les plus hautes productions de lait tandis qu'en seconde lactation, ce furent les Chamoisées. L'accroissement des productions a été important entre première et seconde lactation. Les mises bas de février ont enregistré les productions les plus élevées. Les taux de matières grasse et protéique ont accusé de faibles variations saisonnières. A l'exception de la parité 1 oú elles augmentaient, les productions de lait, matière grasse et protéine tendaient à diminuer avec l'age. Une diminution des taux avec l'age a été observée. Les données ont permis d'établir de nettes différences de production entre la première et la seconde parité à ages identiques; cependant leur nombre encore limité n'a pas permis d'apprécier les effets d'intéractions age × parité, age × mois de mise bas on troupeau-année × mois de mise bas. Les valeurs de R(2) associées aux effets ont été: pour troupeau-année 43 à 52% et 22 à 36%, pour race 3 à 11% et 4 à 12%, pour mois de mise bas 6 à 10% et 2 à 5%, et pour l'age à la mise bas 3 à 7% et 1 à 17%, respectivement pour les primipares et les multipares. ZUSAMMENFASSUNG: Einfluss von Laktationsnummer, Rasse, Herde-Jahr, Wurfmonat und -jahr auf Milch-, Fett- und Proteinertag und Fett- und Milchprozente bei belgischen Milchziegen Die Gesamtlaktationsleistungen wurden aus den Stichtagsleistungen mit der Methode von Fleischmann berechnet. Laktationsleistungen von mehr als 250 Tagen Dauer wurden auf 250 Tage standardisiert, Teillaktationen (Minimum 25 Tage) auf 250 Tage extrapoliert und Fett- und Proteingehalte aus den Leistungen abgeleitet. Von 2562 Ziegen der Rassen Anglo-Nubier, Gemsfarbige Gebirgsziege, Saanen sowie Kreuzungen standen Daten von 2997 Laktationen zu 250 Tagen zur Verfügung. Die Daten wurden in erste und folgende Laktationen sowie nach Wurfmonat (Dezember, Januar, Februar, M?rz, April bis Juli, August bis November) gruppiert. Die Analyse der Daten wurde mit einem Modell fixer Effekte vorgenommen, das Herde-Jahr, Rasse, Wurfmonat und- alter beinhaltete. Ausser den Effekten des Wurfalters auf Fettprozente und des Wurfmonats auf Proteinprozente in der ersten Laktation waren alle untersuchten Parameter signifikant. In der ersten Laktation erzielten die Saanenziegen, in den folgenden Laktationen die Gemsfarbigen die h?chste Milchleistung. Zwischen der ersten und den folgenden Laktationen stieg die Milchleistung stark an. Würfe im Februar verzeichneten die h?chste Milchleistung. Monatliche Variationen in Fett- und Proteinprozenten über alle Laktationen waren zwar meist signifikant, aber von geringem Ausmass. Die Leistungen erh?hten sich in der ersten Laktation mit steigendem Alter. In den folgenden Laktationen stiegen die Milchleistung bis zum Alter von 25 bis 30 Monaten und die Fett- und Proteinertr?ge bis 40 Monate; danach nahmen die Leistungen ab. Fett- und Proteinprozente erh?hten sich bis zu einem Alter von 15 bis 17 Monaten und nahmen dann ab, um bei 25 Monaten die tiefsten Werte zu erreichen. In der Folge nahmen die Werte ab 32 Monaten wieder zu, um sich bei 50 Monaten zu stabilisieren. Die Bereiche der R(2) der verschiedenen Effekte lagen für Herde-Jahr bei 43 bis 52%, die Rasse bei 3 bis 11%, den Wurfmonat bei 6 bis 10% bzw. 2 bis 5% (erste und folgende Laktationen) und das Wurfalter bei 3 bis 7% bzw, 1 bis 17%.     

奶牛体况与胎次、泌乳阶段和生产性能的关系

奶牛体况评分是指可根据奶牛身体各部位综合得分来衡量牛的膘情,并用于管理奶牛营养和健康的一种重要方法。某代表性奶牛场泌乳期奶牛的体况评分结果表明,奶牛体况与乳蛋白率、305d估计产奶量呈极显著正相关(P0.01);第3胎次奶牛体况最好,极显著优于其它胎次(P0.01);泌乳后期奶牛体况极显著优于其它泌乳阶段(P0.01);奶牛体况与体细胞分之间显著正相关(P0.05)。根据奶牛体况评分结果可预测牛奶产量和品质。生产中应通过加强营养和改善饲养管理条件等措施使奶牛体况处于合理范围,以获得产量和品质俱佳的牛奶。     

Milk losses associated with somatic cell counts per breed, parity and stage of lactation in Canadian dairy cattle

The reduction in milk production caused by subclinical mastitis in dairy cattle was assessed through the regression of test day milk yield on log-transformed somatic cell counts (LnSCC). Data was obtained from Valacta, Quebec, and a total of 312,756 test day records from Ayrshire cows and 1,869,785 test day records from Holstein cows were included in the analyses. A segmented regression was fitted to estimate the cutoff point in the LnSCC scale where milk yield starts to be affected by mastitis. The statistical model used to explain daily milk yield included the effects of herd–year-season of test (random), days in milk, age at calving and LnSCC, and analyses were performed by breed, parity and stage of lactation. The cutoff point where milk yield starts to be affected by changes in LnSCC was estimated from data to be around 2 (approximately 7400 cells/mL) for Canadian Ayrshires and Holsteins. Milk losses per unit increase in LnSCC varied from 0.55 to 0.84 kg/day in first lactation Ayrshires, from 0.33 to 0.55 kg/day in first lactation Holsteins, from 0.74 to 2.45 kg/day in adult Ayrshires and from 0.77 to 1.78 kg/day in adult Holsteins. Daily milk losses caused by changes in LnSCC were dependent on breed, parity and stage of lactation, and these factors should be considered when estimating losses associated with subclinical mastitis.     

复合酶制剂对瘤胃发酵及泌乳早期奶牛生产性能的影响

本试验旨在研究添加不同水平复合酶制剂对瘤胃发酵及奶牛生产性能的影响。试验一以奶牛全混合日粮作为底物进行体外瘤胃发酵试验,分为4组,即对照组不添加酶制剂,试验1、2和3组的酶制剂添加量分别为日粮浓度的0.10%、0.15%和0.20%,每组设9个重复。每个重复准确称取0.500 g底物,在体外发酵产气自动记录装置上发酵48 h,测定其发酵参数和营养物质降解率。结果表明:复合酶制剂显著提高发酵液中总挥发性脂肪酸和乙酸浓度(P<0.05);试验组中粗蛋白(P<0.05)和中性洗涤纤维(P<0.01)降解率显著高于对照组。试验二选择体重、胎次、泌乳天数和产奶量相近的泌乳早期荷斯坦奶牛36头,采用随机区组设计分为4组,即对照组和试验1、2和3组,对照组不添加酶制剂,试验1、2和3组分别添加0.10%、0.15%和0.20%的酶制剂,每组9个重复,试验期8周,测定产奶量和乳成分含量,计算3.5%乳脂校正乳。结果表明:复合酶制剂显著提高3.5%乳脂校正乳产量(P<0.05),0.10%、0.15%和0.20%组比对照组分别提高3.88、4.27和2.26 kg·d^-1。0.15%组的乳脂率显著高于对照组(P<0.05),比对照组高12.7%。结论添加复合酶制剂有利于瘤胃发酵和提高生产性能,且添加量为0.15%时效果较好。     

Effects of breed and feed supplementation on the fertility of cows developed for milk production in Zimbabwe

Forty-six indigenous Sanga-type (Nkone and Tuli breeds) cows and 46 crossbred (Nkone x Jersey and Tuli x Jersey) cows were randomly allocated to four treatment combinations in a 2 x 2 factorial arrangement with two breeds and two dietary levels, a control diet and a diet supplemented with dairy meal containing 14 per cent crude protein at the rate of 2 kg per cow per day. The progesterone concentration was measured in milk samples taken three times a week from 10 days postpartum for up to 200 days, and the cows' bodyweights and body condition scores were recorded fortnightly. The pregnancy rate in the crossbred cows was significantly higher (P<0.05) than in the indigenous cows, and the assumed pregnancy loss rate 30 days after conception was significantly higher (P<0.05) in the indigenous cows than in the crossbred cows. The supplemented crossbred cows had a lower pregnancy loss rate than the supplemented indigenous cows (P<0.05). All the supplemented indigenous cows that lost pregnancies were in their first parity, whereas all the crossbred cows that lost pregnancies were multiparous and were not supplemented. The indigenous cows weighed significantly more (P<0.05) than the crossbred cows irrespective of diet, and the supplemented cows of both breeds weighed more (P<0.05) than the control cows. The supplemented indigenous cows had significantly higher (P<0.05) body condition scores than the control cows. The mean dairy milk yield of all the breeds was generally low but significantly higher (P<0.05) in the crossbred than in the indigenous cows.     

Intramammary antibiotics in dairy goats: effect of stage of lactation, parity and milk volume on withdrawal periods, and the effect of treatment on milk compositional quality

The length of the antibiotic withdrawal period after intramammary treatment was influenced by the milk yield of dairy goats during this trial. Shorter withdrawal periods were seen in relatively high yielding dairy goats (production above 1.5 l per day) compared to low producers (less than 1.3 l per day). High yielding goats treated with Curaclox LC (Norbrook [Pharmacia AH]) had a withdrawal period of 42 h, while low yielding goats, treated with the same product, had a withdrawal period of 74 h. The recommended withdrawal period for Curaclox LC for use in cattle is 72 h. Relatively high yielding goats treated with Rilexine 200 LC (Logos Agvet [Virbac]) had a significantly shorter withdrawal period (37 h) than that recommended for use in cattle (96 h). Low yielding goats treated with Spectrazol Milking Cow (Schering-Plough Animal Health) had a significantly longer (95 h) withdrawal period than that recommended for use in cattle (60 h). Withdrawal periods were also influenced by stage of lactation and parity. There was a moderate positive correlation between lactation number and withdrawal period, as measured by TRIS (R2 = 0.621), and a moderate negative correlation between stage of lactation and withdrawal period (R2 = -0.669). In Trials 1, 2 and 3 combined there was a moderate negative correlation between withdrawal period and volume (R2 = -0.511) and a strong positive correlation between withdrawal period and lactation number (R2 = 0.720). The differences in percentage milk fat, protein and lactose before, during and after treatment were not statistically significant except in Trial 3 (Curaclox LC and Rilexine 200 LC) where protein and lactose differed significantly. In Trial 2 (Spectrazol Milking Cow) milk fat percentages differed significantly between treatment and control groups as did protein percentages in Trial 3. These differences are however, not biologically meaningful.     

复合半胱胺盐酸盐对泌乳中期奶牛产奶性能的影响

试验用动物为 98头多胎黑白花奶牛。试验开始时的平均泌乳天数为 1 3 5 d,日平均产奶量 3 5 kg。根据奶产量( M)将 98头奶牛分成 4个组 ,各产量组随机划分复合半胱胺盐酸盐处理 ( CSC,n=49)与对照 ( n=47) ,试验期计 1 3周。 4种剂量复合半胱胺盐酸盐 ( 2 0 0 0 U / d处理 1周 ,3 0 0 0 U/ d处理 4周 ,40 0 0 U/ d处理 5周 ,60 0 0 U/ d处理 3周 )对不同生产水平奶牛生产性能的影响如下 :第 1组 ( M<3 0 kg/ d)试验期内 ( 1 3周 )平均日产奶量增加 1 2 .1 % ( P<0 .0 1 ) ,4种剂量的效果分别为 1 1 % ( P=0 .1 3 )、1 8.6% ( P<0 .0 5 )、1 9.4% ( P=0 .1 3 )和 1 1 .7% ( P<0 .0 5 ) ;其它 3个组奶未见显著变化。第4组 ( M>40 kg/ d)乳脂率 ( % )提高 1 6.1 % ( P<0 .0 1 ) ,乳蛋白含量 ( % )提高 7.9% ( P<0 .0 5 ) ;第 2组 ( 3 0 3 5 kg/d)乳脂率 ( % )和乳蛋白含量 ( % )也显著提高 ( P<0 .0 5 ) ;4个产量组的平均乳蛋白含量 ( % )显著提高 ( P<0 .0 5 )。并且 ,第1和第 4组的乳蛋白合成及 FCM( fat corrected milk)产量趋于增加 ( 0 .0 5 相似文献   

Impact of bovine somatotropin administration beginning at day 70 of lactation on serum metabolites, milk constituents, and production in cows previously exposed to exogenous somatotropin.

Metabolic and production responses are reported for 72 cows treated with bovine somatotropin (BST) for 30 days starting at day 70 of lactation. Of these 72 cows, 48 had been exposed in the preceding lactation to long-term treatment with BST at 3 dosages and 24 (controls) had not been given BST. Approximately half of the cows in each group were parity-2 cows, the rest were older. Comparisons between groups were made separately for parity-2, and older cows. Analyses, using pretreatment values of each variable as a covariate, indicated that older cows, but not parity-2 cows, significantly (P less than 0.05) increased milk production during treatment. Parity-2 cows, however, had a significantly higher milk fat percentage than controls following treatment. Cows treated with 51.6 or 86 mg BST/d in both parity groups had significantly higher serum-free fatty acids than controls. Estimated net energy balances were significantly lower for older treated cows, but did not significantly differ from controls for parity-2 treated cows. Older cows in the 86 mg of BST/d group tended to have higher concentrations of blood glucose than did older control-group cows. Treatment with BST did not significantly increase serum ketone concentrations in any group of animals, and none of the cows developed clinical ketosis during this period. Estimated net energy balance (ENEB) during treatment was a significant (P less than 0.05) covariate for free fatty acid concentrations in older cows and for milk fat percentage in parity-2 cows. Covariate adjusted analyses, using ENEB during treatment as a covariate, indicated that lipolytic stimuli already acting may be enhanced by treatment with BST, but a negative energy balance was not a necessary precondition for free fatty acid concentrations to increase following somatotropin treatment. Similarly, milk fat percentages for parity-2 treated cows were significantly (P less than 0.05) higher during treatment than controls when ENEB during treatment was used as a covariate. Increased milk fat concentrations in parity-2 treated cows were not associated with significant increases in the ratio of C18:C4-10 milk fatty acids, indicating that increased milk fat resulted from either an increase in incorporation of C18 fatty acids into milk fat coupled with an increase in de novo mammary synthesis of C4-10 milk fatty acids or an increase in C12-16 fatty acids that may arise either from increased tissue mobilization, from diet, or from de novo mammary synthesis.     

Dietary yeast culture supplementation of mares during late gestation and early lactation: Effects on milk production, milk composition, weight gain and linear growth of nursing foals

This study examined the effects of dietary supplementation of pregnant and lactating mares with concentrated dried live yeast culture on the nutrient content and rate of production of milk during early lactation and on the growth of their nursing foals. Pregnant mares were fed the same diets, with or without 20 g/day of yeast culture, from 4 weeks before foaling through the eighth week of lactation. Milk production at the onset of lactation, as measured by the weigh-suckle-weigh technique, was significantly stimulated by yeast culture supplementation, although the effect was only temporary. However, the nutrient composition of mares milk was altered by continued yeast culture supplementation through at least the eighth week of lactation. Gross energy (kcal/100 g milk), sugar, fat, protein and total amino acid contents (g/100 g milk) were significantly increased. The concentrations of a number of individual amino acids tended to be greater in the milk of supplemented mares, but most of these individual differences were not statistically significant. The intakes of energy (Mcal/day), sugars, fat, protein, total amino acids, leucine, lysine, serine and valine (g/day) were significantly greater by the foals nursing supplemented mares through 8 weeks. The foals nursing supplemented mares exhibited significantly greater rates of gain by the fourth week of life, and faster growth at the withers after 6 weeks. The efficiency of converting mare feed to neonatal body mass was 24% greater in the foals of supplemented mares, These data indicate that supplementing mares with dietary yeast culture during early lactation resulted in more efficient and rapid growth of their nurslings.     

In vitro phagocytic activity of milk neutrophils during lactation cycle in Murrah buffaloes of different parity

Milk samples were collected from 34 lactating Murrah buffaloes on days 0, 5, 15, 30, 45, 60, 90, 120, 150, 180, 210, 240, 270 and day 300 after calving. Milk somatic cell counts (SCC) were highest in multiparous buffaloes . Milk SCC were significantly lower in buffaloes of third and fourth parity during early lactation and than increased significantly (p < 0.01) by the end of lactation. Milk neutrophils were significantly lower in all the buffaloes during early lactation, but increased significantly (p < 0.01) afterwards. Milk lymphocytes were significantly higher during early lactation, but decreased significantly (p < 0.01) by the end of lactation. Phagocytic activity (PA) was highest in day 1 colostrum and then decreased significantly (p < 0.01) by the fourth milking in buffaloes of second, third and fourth parity . Phagocytic index (PI) was also highest in colostrums of primiparous buffaloes. Irrespective of parity, maximum PA and PI was observed during mid lactation. In terms of in vitro phagocytic activity, early lactation is the most critical period followed by late and mid lactation.     

Effects of malic acid on feed intake, milk yield, milk components and metabolites in early lactation Holstein dairy cows

The objective of this study was to evaluate the effects of malic acid (MA) on feed intake, milk yield and composition, blood metabolites and energy balance in early lactation Holstein dairy cows from 1 to 63 day in milk (DIM). Twenty-eight multiparous Holstein dairy cows, blocked by lactation number, previous 305-d mature equivalent milk production, and expected calving date, were arranged into four groups in a randomized block design. Treatments were: control (without MA), LMA, MMA and HMA with 70, 140 and 210 g malic acid per cow per day, respectively. The supplement of food grade MA (99.8% of MA) was hand-mixed into the top one-third of the daily ration. Cows were fed ad libitum a total mixed ration consisting of equal proportion of forage and concentrate. Milk yield increased (P = 0.04), but feed intake and milk components were not affected (P > 0.05) by MA supplementation. The energy balance, expressed as the difference between energy input and output, tended to be higher (P = 0.08) for MA supplemented cows during the 63-DIM period MA and supplemented cows showed a trend (P = 0.07) toward less loss of BW during the 63-day period, especially during the first 21-day of lactation. Concentrations of plasma glucose and serum insulin were higher for cows fed LMA, MMA, and HMA relative to control and linearly (P < 0.01) increased with increasing MA supplementation. Concentrations of non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA) and urine ketones were lower for MA-supplemented cows at 7, 14 and 21 DIM of lactation and linearly (P < 0.01) decreased with increasing MA supplementation. Although feed intake was not affected, milk yield increased, MA-supplemented cows experienced higher concentrations of plasma glucose and serum insulin, lower concentrations of plasma BHBA and NEFA, and lower concentrations of urine ketones, suggesting that nutrient digestibilities and energy availability may have been improved.