哺乳期云上黑山羊羔羊生长规律及影响因素研究

为探索哺乳期云上黑山羊羔羊生长发育规律及其影响因素,本实验选取云上黑山羊初生羔羊60只,公、母各半,从出生开始直至90日龄断奶,每10 d进行1次体重测定,进行生长发育分析、趋势拟合和影响因素分析。结果表明:1～90日龄羔羊体重与日龄呈直线回归,公、母羔羊的回归直线差异极显著(P0.001);羔羊哺乳期日增重呈现波动变化,日增重类型通过聚类可分为0～10和70～90日龄为生长速度最快、60～70日龄生长速度次之、10～60日龄生长速度最慢3类;母羔的整个哺乳期生长与母羊产后体重、同窝羔羊数、窝重有显著相关(P0.05);除去20、60日龄体重外,母羔的其他哺乳期日龄体重与母羊年龄和胎次有显著相关(P0.05);公羔在整个哺乳期生长与母羊产后体重有显著相关,哺乳期早期生长与母羊年龄、胎次和窝重有显著相关(P0.05)。综上可知,云上黑山羊哺乳期羔羊体重与日龄呈直线回归,营养是影响羔羊生长的最主要因素,胎儿期的生长发育、母羊的母性行为对羔羊生长的影响取决于羔羊性别。     

澳洲美利奴公羊对鄂尔多斯细毛羊羔羊初生重影响的研究

为了探讨利用澳洲美利奴公羊导血改良鄂尔多斯细毛羊对羔羊初生重的影响。选择300只饲养管理水平相近,体重、胎次基本相同的鄂尔多斯细毛羊基础母羊,随机分为两组,分别用澳美公羊和鄂尔多斯细毛羊种公羊进行人工授精,记录羔羊初生重。结果表明：澳美杂交后代单羔公羔和母羔平均初生重分别为4．62kg±0．77kg和4．40kg±0．78kg;鄂尔多斯细毛羊单羔公羔和母羔平均初生重分别3．56kg±0．62kg和3．38kg±0．38kg;澳美杂交后代双羔公羔和母羔平均初生重分别为3．66kg±0．74kg和3．86kg±0．58kg;鄂尔多斯细毛羊双羔公羔和母羔的平均初生重分别为3．22kg±0．67kg和2．98kg±0．61kg。澳美杂交后代羔羊的初生重极显著高于鄂尔多斯细毛羊羔羊（P〈0．01）。     

白萨福克羔羊和特克塞尔羔羊早期生长发育的比较研究

试验对白萨福克羊(White Suffolk)和特克塞尔羊(Texel)两个肉羊品种的羔羊在6月龄以前的生长发育进行了比较研究。结果表明:白萨福克羔羊和特克塞尔羔羊初生重大,除白萨福克母羔外,其余羔羊初生重都在5 kg以上,其中白萨福克公羔的初生重最大;4月龄时,白萨福克公羔体重达到32.88 kg,显著高于特克塞尔公羔(P<0.05),极显著地高于特克塞尔母羔(P<0.01);6月龄时白萨福克公羔体重达到42.60 kg。白萨福克羔羊2月龄时的绝对生长速度最大,公羔日增重达到256.15 g,母羔达到236.67 g;特克塞尔羊从出生到1月龄,绝对生长和相对生长比白萨福克羊要高一些,但是白萨福克羊保持快速生长发育的持续期较特克塞尔羊相对较长。白萨福克羔羊从母乳到饲草饲料过渡较好,断奶后适应性要好于特克塞尔羔羊,从4月龄到6月龄的体重、体尺高于特克塞尔羔羊。在整个测定阶段,白萨福克公羔和母羔的体躯均比特克塞尔公羔和母羔的体躯长,白萨福克公羔体高比特克塞尔公羔的体高要高。     

河南大尾寒羊繁殖性能的观察与统计分析

对河南大尾寒羊繁殖性能进行了观察与统计分析。大尾寒羊母羊初配月龄约为8月龄。1~8胎次平均产羔率为249.27%,总的单羔率、双羔率、三羔率、四羔率及五羔率分别为8.00%、47.82%、36.36%、6.55%和3.27%。产双羔的母羊比率极显著高于产单羔、四羔和五羔的母羊比率(P<0.01);产三羔的母羊比率极显著高于产五羔的母羊比率(P<0.01)、显著高于产单羔及四羔母羊比率(P<0.05)。1~6胎产羔率总的趋势是随着胎次的增加而上升,7~8胎逐渐降低。胎产羔数与胎次回归方程的决定系数为R2=0.991 2。据回归方程计算了每胎的产羔估计值,并以5、6胎校正产羔值的简单平均数为基准计算了各胎次的校正系数。胎产羔数对初生重、断奶体重有显著或极显著的影响(P<0.05或P<0.01),随胎产羔数的增加,初生重和断奶体重减小。     

澳洲萨福克羊和杜泊羊在河北地区饲养的生产性能测定

为了分析澳洲萨福克和杜泊羊在河北地区的纯繁及适应性,试验对母羊胎产羔数,对羔羊初生重、45日龄断奶体重及日增重、2.5月龄体尺等生长发育指标进行测定。结果表明:萨福克和杜泊羊平均胎产羔数分别为(1.39±0.38)只和(1.61±0.49)只,二者无显著差异(P0.05);萨福克公羔初生重为(3.64±0.54)kg,45日龄体重为(21.07±0.87)kg,均显著低于杜泊公羔(P0.05);萨福克母羔初生重、45日龄体重与杜泊母羔均无显著差异(P0.05);萨福克公羔与杜泊公羔45日龄断奶平均日增重无显著差异(P0.05);萨福克母羔45日龄断奶平均日增重显著低于杜泊母羔(P0.05);萨福克羊2.5月龄腰角宽显著低于杜泊羊(P0.05),体高、体长、胸围、胸宽、管围等指标均无显著差异(P0.05)。说明澳洲萨福克和杜泊原种绵羊引入到河北地区后,在舍饲条件下生产性能得到了充分发挥,能够适应当地生态气候条件。     

不同蛋白水平颗粒料对西农萨能奶山羊羔羊哺乳期生长发育的影响

为了筛选西农萨能奶山羊羔羊哺乳期全价颗粒料配方,本试验采用2×3两因子设计,选用出生日期相近(5d之内)、体重相近(3.66±0.69kg)的健康西农萨能奶山羊初生羔羊53只(公羊26只、母羊27只),按性别和蛋白质水平随机分为6组(A、B、C为三组母羊;D、E、F为三组公羊),试验期为120d,并分为1~60日龄和61~120日龄两个阶段,两阶段颗粒料苜蓿草粉含量分别为10%和20%,蛋白质水平分别为18%、21%、24%和15%、18%、21%,哺乳期自由采食干草,试验期间采集奶样和饲料样,记录羔羊采食量和生长发育数据。结果表明,试验期间公羔日增重显著高于母羔(P0.05);1~60日龄,A、D组羊羔具有较大的日增重,饲料报酬高,且D组日增重显著高于E、F组(P0.05);61~120日龄,D组具有最大日增重,随着蛋白水平的升高,公羔日增重呈现出降低的趋势,C组母羔显著大于A、B两组(P0.05),公羔间日增重差异不显著(P0.05);饲喂不同蛋白水平颗粒料对哺乳期羔羊腹泻率和血液生化指标无显著影响。试验表明,1~60日龄,蛋白质水平为18%的颗粒料组羔羊生长发育最快,饲料报酬高;61~120日龄,蛋白质水平为21%的颗粒料组母羔增重快。     

杜湖杂交F1代与湖羊羔羊生长性能和血液生理指标比较研究

为了评定杜泊羊与湖羊杂交F1代和湖羊羔羊在河北省邢台地区的生长发育和身体状况，试验对二者从初生到断奶期间的成活状况、生长性能及断奶时的血液生理指标进行了比较分析。结果表明：杜湖杂交F1代和湖羊羔羊从初生到断奶期间的成活率分别为100%和95%;体重的累积生长中，除了初生重外，杜湖杂交F1代公羔、母羔各年龄段的体重均高于湖羊，其中在15日龄时二者差异显著(P<0.05);绝对生长中，初生～15日龄杜湖杂交F1代公羔、母羔体重均极显著高于湖羊(P<0.01);相对生长中，初生～15日龄，杜湖杂交F1代公羔、母羔体重均高于湖羊，其中公羔差异极显著(P<0.01),母羔差异显著(P<0.05)。杜湖杂交F1代公羔、母羔的大部分体尺指标均高于湖羊，其中1月龄公羔的腰角宽差异显著(P<0.05),断奶母羔的胸围差异极显著(P<0.01)。杜湖杂交F1代和湖羊公羔、母羔大多数血液生理指标均在标准参考值内。说明杜湖杂交F1代羔羊的成活状况、生长性能和断奶时的血液生理指标均表现出较强的杂种优势，可在当地大力推广。     

湖羊胎产羔数对羔羊生长发育的影响

为了研究不同胎产羔数湖羊的泌乳量和羔羊的生长速度,以便进行科学饲养管理,该研究随机选择同期产双羔、三羔、四羔母羊各3只,对其产奶量、羔羊初生重及4月龄前日增重进行了测定,分析对生长发育的影响。结果表明:双羔羊初生重最大,平均为3.82 kg,显著高于三羔羊的3.21 kg和四羔羊的2.80 kg(P0.05);所有羔羊在2月龄前生长速度最快,双羔、三羔和四羔平均日增重分别为279.80 g、223.40 g和200.20 g,各组间差异显著(P0.05);虽然断奶应激对羔羊的生长速度有一定影响,但双羔羊2～4月龄日增重仍然最高,为228.50 g,显著高于四羔组(P0.05);另外,双羔羊的总吮乳量和日吮乳量为52.30 kg和0.88 kg,显著高于三羔组和四羔组(P0.05)。因此,湖羊同胞产羔数越多羔羊初生重越小,羔羊吮乳量越少,早期生长速度较慢。但在良好的饲养管理条件下,羔羊断奶后的代偿性生长可在一定程度上弥补初生重小所造成的影响。研究结果为不同胎产羔数湖羊及其羔羊的饲养管理提供科学依据,即多胎湖羊应分群饲养管理,羔羊早期锻炼采食。     

湖羊在西北干旱温差较大地区繁殖性能观测报告

经过对甘肃金昌元生湖羊种羊场2012~2014年间湖羊母羊产羔数和羔羊断奶前生长发育情况观察、分析,发现湖羊在西北干旱温差较大的金昌地区繁殖性能表现良好,其第一、二、三胎产羔率分别达到191.9%±0.542、226.8%±0.737和271.5%±0.901;前三胎羔羊初生重分别是2.93kg、3.50kg、3.23kg;前三胎羔羊60日龄平均断奶重分别是18.34kg、19.03kg、17.12kg,断奶前平均日增重分别达到256g、257g、233g。母羊3岁前,随胎次增加,产羔数显著上升;羔羊初生重随同胎数增加而降低;羔羊断奶前日增重随同胎羔羊数的增加而降低。但在良好饲养管理条件下,多胎母羊的贡献远高于单胎母羊。     

哺乳期放养云岭山羊羔羊生长曲线拟合分析

[目的]探讨放养云岭山羊羔羊在哺乳期的生长发育规律。[方法]选取待产母羊24只,共产羔36只（公羔17只,母羔19只）,测定0~8周龄羔羊的体重（每周测定1次）和体尺（隔1周测定）。采用Logistic、Gompertz和Von Bertalanffy 3种非线性模型对0~8周龄公羔、母羔的体重进行生长曲线拟合,并对初生体重以及试验末体重进行相关性分析。[结果]采用的3种非线性模型均能够很好地拟合哺乳期云岭山羊羔羊生长曲线,拟合度均大于0.99。Gompertz和Von Bertalanffy模型拟合效果较优,公羔的生长发育曲线拐点时间分别为3.212周和2.862周,拐点体重分别为5.691、5.352 kg;母羔拐点时间分别为1.927周和1.325周,拐点体重分别为4.532、3.960 kg;公、母羔之间拐点周龄和拐点体重存在差异,公羔平均在3.037周龄体重增长速度达到最大,而母羔平均在1.626周龄体重增长速度达到最大。初生重对羔羊试验末体重有极显著（P<0.01）影响。[结论]该研究结果可为今后对哺乳期放养云岭山羊羔羊进行合理补饲提供依据。     

Lactational and subsequent reproductive responses of lactating sows to dietary lysine (protein) concentration

Gilts (n = 208) were used to evaluate the effect of lysine (protein) intake over three parities on lactation and subsequent reproductive performance. Sows were assigned randomly to one of five experimental diets at each farrowing. The five corn-soybean mealbased lactation diets contained increasing concentrations of total lysine (.60, .85, 1.10, 1.35, and 1.60%) and CP (14.67, 18.15, 21.60, 25.26, and 28.82%). Other amino acids were provided at a minimum of 105% of the NRC (1988) ratio to the lysine requirement. Sows had ad libitum access to their assigned diets from parturition until weaning (19.5+/-.2 d postpartum). All sows were fed a common gestation diet (14% CP and .68% lysine) from weaning to next farrowing. Litter size was standardized by d 3 postpartum to 10 pigs in parity 1 and 11 pigs in parity 2 and 3. Increasing dietary lysine (protein) linearly decreased (P<.05) voluntary feed intake of parity 1 (from 5.4 to 4.6 kg/d), 2 (from 6.5 to 5.8 kg/d), and 3 sows (from 6.8 to 6.2 kg/d). With the increase of dietary lysine (protein) concentration during lactation, litter weight gain responded quadratically (P<.05) in all three parities. Maximal litter ADG was 2.06, 2.36, and 2.49 kg/d in parities 1, 2, and 3, respectively, which occurred at about 44, 55, and 56 g/d of lysine intake for parity 1, 2, and 3 sows, respectively. Increasing dietary lysine (protein) had no effect (P>.1) on sow weight change, weaning-to-estrus interval, and farrowing rate in all three parities and no effect on backfat change in parity 2 and 3, but tended to increase backfat loss linearly (P<.1) in parity 1. A linear decrease of second litter size (total born, from 11.7 to 10.1, P<.1; born alive, from 11.0 to 8.9, P<.01) was observed when dietary lysine (protein) increased during the first lactation. Lysine (protein) intake during the second lactation had a quadratic effect on third litter size (P<.05; total born: 13.3, 11.2, 11.6, 11.9, and 13.6; born alive: 11.8, 10.1, 10.3, 11.2, and 12.4). However, fourth litter size was not influenced by lysine (protein) intake during the third lactation. These results suggest that the lysine (protein) requirement for subsequent reproduction is not higher than that for milk production. Parity influences the lysine (protein) requirement for lactating sows and the response of subsequent litter size to previous lactation lysine (protein) intake.     

Guinea-pig productivity under traditional management

Results of a 12 month study of traditional guinea-pig production in the western highlands of Cameroon are reported. The mean age of guinea-pigs (Cavia porcellus L.) at first parturition, kidding interval and litter size at birth were 126.30±10.40 d, 64.8±1.70 d and 1.63±0.26 kids respectively. The annual reproductive rate was 9.18 kids/breeding doe while the doe post-partum weight was 530 g. Mean body weights at birth, presumed weaning (21 d) and 15 weeks of age were 78.36±3.20, 147.51±8.10 and 418.88±32 g respectively. Type of birth and sex had a significant effect on body weight at all ages. Birth weight dropped significantly from 83.88±2.87 g for singles to 81.57±3.40 g for twins, 74.25±2.39 g for triplets and 73.75±4.12 g for quadruplets. These differences were maintained to maturity (15 weeks). Males were generally heavier than females. Mortality rates were relatively high among kids: 24% at birth, 39% at 3 weeks and 40% at 15 weeks. Productivity indices were 0.827 kg of young weaned per doe per year, 1560 g of young weaned per kg of doe per year and 2.52 kg of young weaned per kg metabolic weight (kg^0.75) of female per year.     

Birth weight,birth type and pre-weaning survivability of West African Dwarf goats raised in the Dangme West District of the Greater Accra Region of Ghana

A study was conducted on 441 West African Dwarf goat (WADG) kids born from September 1999 to August 2002 at three locations in the Dangme West District of the Greater Accra Region in Ghana to determine the effect of environmental factors on birth weight, birth type and pre-weaning survivability. The overall mean birth weight was 1.32 ± 0.01 kg. Birth weights were similar (p >0.05) between single births (1.43 ± 0.04 kg) and twins (1.34 ± 0.03 kg), but singles were significantly heavier (p < 0.05) than triplets (1.24 ± 0.05 kg). Kids born in the major wet season recorded the best mean birth weight (1.37 ± 0.04 kg). Sex, parity of does, and year of birth of kids had no significant (p > 0.05) effect on birth weight. Mean litter size was 1.93 ± 0.03. Does that kidded in the dry season had a significantly (p < 0.05) higher litter size (2.05 ± 0.06) than those that kidded in the minor wet season (1.80 ± 0.10). Litter size of first-parity kids was significantly smaller (p < 0.05) than in subsequent parities. Litter size dropped significantly (p < 0.05) from year 2 (2.03 ± 0.07) to year 3 (1.83 ± 0.07). Pre-weaning survivability was 79.1% and season of kidding had a significant (p < 0.05) effect on survivability. Survivability of quadruplets (61.8%) was significantly (p < 0.05) lower than in the other birth types.     

The Role of Bioactive Tannins in the Postpartum Energy Retention and Productive Performance of Goats Browsed in a Natural Rangeland

The role of bioactive tannins in browse in the postpartum performance of goats grazed under natural range conditions was studied using 40 yearling Mubende goats (20+/-0.32 kg). In a completely randomized design, goats of one group (n = 20) received a daily drench of 50 g per goat of polyethylene glycol (PEG) of molecular weight 4000 given as a condensed tannin (CT) deactivator, and goats of the other group (n = 20) acted as the control (no PEG). Mean birth weights, live weight gains, abortion and twinning rates, litter size and tissue energy retention were measured. The PEG drench resulted in lower postpartum weight gains and tissue energy retention (p < 0.05). Postpartum weekly weight loss per doe was 0.65 kg in the PEG group and 0.46 kg in the control group, while tissue energy loss was 17.7 MJ per goat in the PEG group and 10.23 MJ per goat in the control group in the first 8 weeks. Net weight gain was observed in the control group at the 11 th week but was delayed in the PEG group (15th week). The PEG group had lower birth weights and higher kids mortalities (p <0.05). Selective feeding in the Ankole rangeland exposes goats to beneficial concentrations of dietary CT with apparent cumulative effects leading to improved postpartum performance of does and kids.     

Effect of dietary crude protein level on the reproductive performance and growth of New Zealand white rabbits

An experiment utilizing 391 preweaning and 187 postweaning litter records from 145 does was conducted for 12 mo to determine the effect of dietary crude protein level on performance of commercial New Zealand White rabbits. Does and their litters were fed alfalfa-based pelleted diets containing either 17.5, 19 or 20.5% crude protein (CP). In a separate experiment, the 17.5 and 20.5% CP diets were fed during lactation to 10 does to determine nitrogen (N) digestibility and retention. Body weights of does fed 17.5% CP were lower (P less than .01) than for the other treatments after 21 and 28 d of lactation. No differences (P greater than .10) were observed for doe weight at kindling, percentage fertility, litter size, preweaning litter mortality, 1- to 21-d consumption, preweaning feed efficiency and 28- to 56-d average daily consumption, average daily gain and average weight. Total born tended to be higher (P = .07) on higher protein levels but percentage born alive was greatest (P less than .01) on the 17.5% CP diet. Does fed 19% CP tended to have a greater number of parities (P = .06). Other significant differences observed for preweaning litter traits were between 17.5 and 19% CP groups. Does fed 19% CP had heavier litters at birth (P less than .01), at 21 d (P = .05) and 28 d (P = .06) and had greater 1- to 21-d litter gains and 21- to 28-d consumption (P = .05) than those fed 17.5% CP. For postweaning performance, feed efficiency values were lowest and mortality was highest for litters fed 20.5% CP. When litters were switched to different diets after weaning, mortality tended to be higher (P = .07) for animals that were fed 20.5% CP before weaning. The month of experiment effect did not influence any of the characters studied (P greater than .05). Parity number was important for percentage fertility, percentage born alive, litter birth weight and doe weight at 21 and 28 d (P less than .05). Does at first parity showed the poorest performance for all traits (except percentage fertility). Fertility fluctuated throughout the first four parities and then steadily declined. Does fed 20.5% CP had greater apparent dry matter and acid detergent fiber digestibilities and N intakes (P less than .05) and retained 90% more N during lactation (P = .22) than does fed 17.5% CP. Milk production and CP digestibility did not differ between the two diets tested.(ABSTRACT TRUNCATED AT 400 WORDS)     

Effect of passive transfer status on preweaning growth performance in dairy goat kids

OBJECTIVE: To evaluate the effect of passive transfer status (determined from measurements of serum IgG concentration at 24 hours after parturition [sIgG-24]) on preweaning growth performance in dairy goat kids. DESIGN: Prospective observational study. ANIMALS: 20 healthy nursing dairy doe kids in a natural nonintensive breeding environment. PROCEDURES: For each kid, sIgG-24 was measured. Body weight was measured at birth and at the time of weaning 30 days (ie, 29 to 31 days) after birth; average daily gain from birth to day 30 and weight at day 30 were used as measures of preweaning growth performance. Regression analysis was used to evaluate associations between sIgG-24 and measures of preweaning growth performance. RESULTS: Mean +/- SD sIgG-24 was 31.7 +/- 10.3 mg/mL. Mean body weights at birth and weaning were 4.105 +/- 0.981 kg (9.031 +/- 2.158 lb) and 9.310 +/- 2.554 kg (20.482 +/- 5.619 lb), respectively; average daily gain was 0.174 +/- 0.072 kg/d (0.383 +/- 0.158 lb/d). No significant association was detected between sIgG-24 and birth weight. However, sIgG-24 was significantly associated with average daily gain (R(2) = 0.48) and weight at day 30 (R(2) = 0.56). Each increase in sIgG-24 of 1 mg/mL was associated with an increase in average daily gain of 0.005 kg/d (0.011 lb/d) and an increase in weight at day 30 of 0.185 kg (0.407 lb). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that passive transfer status (determined as sIgG-24) was a significant source of variation in preweaning growth performance in dairy doe kids reared in this nonintensive breeding environment.     

Effect of dietary fibre on reproductive performance of sows during the first two parities

The aim of this study was to investigate the effect of dietary fibre on reproductive performance during the first two parities. Gilts were randomly allocated to receive three fibrous diets from days 1-90 of gestation, including low fibre [low fiber (LF), 10.8% neutral detergent fiber (NDF), n=132], middle fibre [middle fiber (MF), 15.8% NDF, n=132] and high fibre diet (HF, 20.8% NDF, n=135), until completion of the second parity. Response criteria included backfat measurements, litter size and pig weight at parturition and day 22 of lactation, weaning-oestrus-interval, oestrus rate, sow farrowing and culling rate, uniformity of newborns and relative organ weights. The results showed sows fed LF diet in parity 1 gained more backfat (p<0.05) during gestation but lost more (p<0.05) during lactation than sows fed HF diet. Furthermore, sows fed LF diet farrowed more pigs (+0.7-1.1 pigs, p<0.05) and pigs born alive (+1.0 pigs, p<0.05) relative to sows fed HF diet. Likewise, sows fed LF and MF diets had greater litter weights at parturition (both p=0.06) and day 22 after lactation (both p<0.05). In parity 2, yet, it was MF diet to increase both total pigs born and pigs born alive (+0.9-1.1 pigs, p<0.05) and litter weight (p=0.05) relative to other diets. After 22 d of lactation, intriguingly, sows fed HF diet had most pigs alive (p<0.01-0.07) and heavier litter weight (p=0.07 or 0.2). Feeding HF diet also increased internal organs weight of newborns (p<0.05). Collectively, feeding LF and MF diets had beneficial effects on litter weight at parturition and day 22 of lactation in parity 1, and feeding MF diet until parity 2 was able to improve litter size and weight at parturition, but this positive effect disappeared after 22 days of lactation, instead feeding HF diet showed the optimal litter performance.     

胎次对杜洛克、长白和大白母猪繁殖性能的影响

为了研究胎次对杜洛克、长白和大白母猪繁殖性能的影响,根据江苏省某国家级生猪核心育种场2009-2011年出生的繁殖母猪资料,分别选取128头杜洛克、681头长白和610头大白母猪共7280窝生产数据,统计分析不同胎次母猪的总产仔数、产活仔数、断奶仔猪数、初生窝重及校正21日龄窝重。此外,依据胎次将母猪分为3个繁殖阶段（1～2胎、3～6胎及7～8胎）来探究品种差异对母猪繁殖性能的影响。结果表明：胎次对母猪繁殖性能有显著影响（P<0.05）,母猪1～4胎的总产仔数、产活仔数、断奶仔猪数及初生窝重随胎次呈增加趋势,第4胎达到高峰,且显著高于其他胎次（P<0.05）;3～6胎繁殖性能较好,7胎之后出现迅速下降趋势;除在第4胎略有下降外,其他胎次的校正21日龄窝重随胎次递增。品种对母猪繁殖性能的影响显著（P<0.05）,长白和大白母猪的繁殖性能均极显著高于杜洛克母猪（P<0.01）;长白母猪的产活仔数和校正21日龄窝重显著高于大白母猪（P<0.05）,2个品种其他繁殖性能无显著差异（P＞0.05）。综上所述,杜洛克、长白和大白母猪的最佳繁殖胎次为3～6胎,长白猪的繁殖性能总体上优于大白猪,就本试验所在的育种场而言,长白猪可能更适合作为二元母猪生产中的母本。     

宁夏地区荷斯坦牛成母牛淘汰情况及长寿性影响因素分析

试验通过收集出生、产犊和离群的记录,探究宁夏地区荷斯坦牛成母牛的淘汰情况,分析影响该地区奶牛长寿性的因素。对15523头荷斯坦牛的生产寿命、在群寿命和利用胎次进行描述性统计,分析淘汰时的胎次、季节和泌乳阶段的分布情况;计算生产寿命、在群寿命和利用胎次之间的表型相关,利用固定模型分析场-出生年、出生季节、牧场规模、淘汰原因和头胎产犊月龄对长寿性的影响。结果显示,宁夏地区荷斯坦牛的平均利用胎次为2.36胎,平均生产寿命为736.59 d。荷斯坦牛成母牛在产后第1个月内的淘汰风险最高,随着泌乳阶段的延长,成母牛在每个胎次内的淘汰风险均逐渐降低;随着淘汰胎次的增加,奶牛淘汰更加集中发生在产后泌乳早期;生产寿命、在群寿命和利用胎次之间存在较高的表型相关(均>0.9),场-出生年、出生季节、牧场规模、淘汰原因和头胎产犊月龄对长寿性有显著影响(P<0.05),春季出生和22月龄头胎产犊的奶牛长寿性表现更好。本研究初步揭示了宁夏地区荷斯坦牛成母牛的淘汰规律和长寿性的影响因素,为宁夏地区牛群选育成母牛长寿性状奠定了基础。