上海野生动物园大熊猫育幼行为初步研究

2017年10月至2018年3月采用连续记录法和焦点取样法,对上海野生动物园熊猫馆的2只雌性大熊猫在育幼期间的时间分配与活动节律进行了初步观察研究。结果表明:2个个体在育幼期间,育幼行为是最主要的行为方式,在育幼前期占90%以上。在整个育幼期间,随时间大熊猫的舔阴和育幼行为呈下降趋势,摄食、休息、活动、求适和其他行为呈上升趋势。但2个个体之间也表现出一定差异:育幼经验不足的个体("芊芊")母性强于育幼经验丰富的个体("思雪"),在育幼期不同阶段,"芊芊"用于护仔、舔仔、哺乳和母仔互动的时间均高于"思雪"。通过对上海野生动物园育幼期大熊猫行为的研究,为圈养育幼期的大熊猫饲养与管理提供科学依据。     

圈养金钱豹行为谱

2005年3月～2006年3月,采取所有事件取样法和目标取样法,对成都动物园圈养的17只金钱豹进行行为观察,在此基础卜制定了行为谱.研究表明:休息、观望、运动是圈养金钱豹的主要行为,占其所有行为的93.1%,休息占其所有行为的54.40%;观望占21.18%;运动占17.53%.     

圈养大熊猫初生幼仔声音通讯行为研究

对很多动物来说,特别是刚出生的、视觉、身体运动能力等发育不健全的幼体,声音信号的识别与传递是其种群长期续存的重要保障。由于大熊猫Ailuropoda melanoleuca新生幼仔不具备自主移动能力且双眼紧闭,主要依靠声音与母体进行交流,因此,利用Shure VP89M指向性麦克风和Tascam DR-100MKII录音设备对0～45 d大熊猫幼仔的声音进行采集,在Adobe audition 3.0内对采集的信息进行分析,同时,利用焦点动物取样法对哺乳期雌性大熊猫的行为进行详细记录。研究结果发现,1)大熊猫幼仔的声音主要为Squawk、Squall和Croak。Squall基频值(1 160.96 Hz±224.99 Hz)和主频值(2 239.94 Hz±742.73 Hz)最高,Squawk的基频值(820.53 Hz±160.45 Hz)和主频值(931.98 Hz±435.12 Hz)次之,而Croak的基频值(728.74 Hz±120.34 Hz)和主频值(735.92 Hz±138.48 Hz)最低;2)幼仔发出叫声后,母兽的回应率和行为类型均随叫声类型不同而不同:母兽对幼仔叫声的回应率为62%,其中Squall的回应率最高(67.4%),回应的行为以舔仔为主;其次是Croak(59.0%),以舔仔为主;而Squawk最低(57.8%),以叼仔为主。大熊猫幼仔初期仅仅依赖声音与母体交流,在充分了解其声音特征的基础上,掌握幼仔与母兽间的互动行为,有助于更深入了解圈养大熊猫的育幼行为,为育幼过程中的人工干预提供科学依据。     

圈养大熊猫同时哺育双胞胎行为观察

2003年,圈养大熊猫"梅梅"首例哺育成活一胎二仔,通过对其近半年的育幼行为观察,结果发现1)母兽主要以同时衔2仔、同时衔和抱2仔二种方式将幼仔抱入怀中哺育;60 d内,育幼姿势以坐位为主,倦卧其次,其它姿势更少,其中坐位随日龄增加逐渐减少,倦卧变化不大.2)母兽活动时间在产仔当天最多,之后显著下降并维持在35.2±0.6%的低水平,47 d后再缓慢上升到108 d后的54.8±0.9%.3)双胞胎幼仔间哺乳的日均次数和时间无显著差异.4)7 d内2幼仔"仔在母身上"的时间占100%,21～23 d后显著减少,而"母体盖仔"、"仔在母身边"和"母仔自然分离"的时间显著增加,但"母体盖仔"的时间在32 d左右后又显著减少;双胞胎分别在与母兽的此四种位置变化的时间上无显著差异.5)母兽的活动、幼仔哺乳日均次数、"母仔自然分离"在全天的日均时间分布有峰、谷变化.6)随幼仔活动能力的逐渐增强,幼仔离"育幼窝"的距离也逐渐增加,双胞胎幼仔离"育幼窝"的远近也有差别.7)母兽分别与其雄性双胞胎幼仔玩耍的时间有显著差异,而两幼仔自玩的时间无差异,此两双胞胎自玩和一起玩耍所用时间远大于分别与母兽玩耍的时间.该研究丰富了大熊猫育幼行为内容,并为以后的大熊猫双胞胎育幼提供了可供参考的行为资料.     

马鹿的圈养种群粪样中性激素水平与繁殖行为的关联

2003年9、10月和2004年4～7月,对黑龙江省兰西县榆林镇禄宝种鹿场圈养的天山马鹿(Cervuselaphus songaricus)进行了行为观察,并利用放射免疫分析法(RIA)测定了马鹿粪样中的性激素水平,包括雄鹿的睾酮.雌鹿的孕酮、雌二醇和雌三醇.结果表明,圈养条件下天山马鹿繁殖行为呈显著的季节变化.雌马鹿性行为的高发期在9月(P＜0.01).在幼仔出生后的6月(高出生月份),嗅仔和舔仔行为显著高于5月和7月(P＜0.05),极显著高于其他月份(P＜0.01);唤仔行为6月份极显著高于其他月份(P＜0.01);哺乳行为发生的高峰期在6、7两个月,而且发生了显著的异常哺乳与异常授乳行为.雄马鹿嗅尿、卷唇、尿喷洒、腺体标记、呜叫与蹄地行为发生频次高发期在9、10月(P＜0.01);饰角发生高峰期在6月,角斗在6月显著高于其他月份;爬胯与搅水或泥浴行为在9、10月显著出现.雄马鹿粪样性激素水平与其繁殖行为呈显著相关;而雌马鹿粪样性激素水平只有孕酮与雌马鹿的部分育幼行为存在显著的相关,与大部分行为不存在显著相关.     

圈养繁殖大熊猫生存力的影响因素分析——基于大熊猫谱系数据

提高圈养繁殖大熊猫存活率是维持圈养种群可持续发展和开展野化放归研究的基础,为了探究圈养繁殖大熊猫生存力的影响因素,基于2019年的大熊猫谱系数据,不仅统计分析了不同年代和不同龄级(月龄、年龄组)圈养繁殖大熊猫的存活率和死亡率,而且利用广义线性模型系统分析了影响圈养繁殖大熊猫存活时间的主要因素。结果表明:1960—1989年圈养繁殖大熊猫的幼仔和种群存活率分别是31.61%和68.10%,1990—2019年为78.39%和94.06%;不同年龄组圈养繁殖大熊猫的死亡率呈"凹型"曲线,即幼年和老年大熊猫死亡率较高(26.85%、26.53%),而亚成年和成年的死亡率偏低(4.56%、12.60%);不同月龄则以初生幼仔(1月龄)的死亡率最高,达22.45%,其余月龄相对较低(0～20%)。广义线性模型分析发现,个体性别、出生年代、母兽来源、母兽产仔年龄、育幼方式和胎儿数量等因素显著影响圈养繁殖大熊猫的存活、死亡和寿命长短。因此,加强大熊猫种源管理、提高人工育幼技术以及优化繁育配对等是大熊猫饲养管理的关键。     

提高圈养大熊猫仔兽存活率的研究

1998～2001年,对提高圈养大熊猫仔兽存活率进行研究,采用了母兽育幼、人工辅助育幼、保姆育幼、人工育幼等多种方法,特别是模仿大熊猫母兽的育幼行为和活动以及用人工巢进行人工育幼。人工巢制作简单,操作方便,育幼时的温度、湿度及呼吸的新鲜空气与母兽育幼环境近似,也便于科技人员观察、抚摩,促进幼仔身体活动及护理幼仔。采集母兽的初乳及常乳饲喂;抽取健康母兽的血液制成口服血浆,适量喂仔;用美国产的两种奶粉配制的人工奶,代替母兽常乳收到良好的育幼效果。在本项研究的4年中,将卧龙大熊猫育幼成活率由54．16％平均提高到90．32％,创大熊猫育幼史的最高水平,为大熊猫的迁地保护提供了新的应用技术和方法。     

毛冠鹿自然育幼行为观察

于2006年6～11月对成都动物园饲养繁殖的毛冠鹿母仔的自然育幼行为采用瞬时观察法,每天8∶00～17∶00进行连续观察,每隔1min收集1次数据。结果显示母舔仔和仔吮乳的行为发生次数在出生20d内较多,之后逐渐下降,到60d以后几乎为0;而仔摄食和排便行为在出生20d以内几乎没有,20d后大幅增加;幼仔的活动频率也逐渐增加,40d以后活动很频繁。不同幼仔间存在个体差异。     

育幼经历对圈养成年雌性大熊猫尿液皮质醇含量的影响

为研究育幼期不同的育幼方式对圈养成年雌性大熊猫Ailuropoda melanoleuca福利状况的影响情况,了解圈养育幼模式可能引发成年雌性大熊猫的应激问题,完善育幼期大熊猫的饲养管理和兽舍参数设计,提高育幼过程中圈养大熊猫福利状况,选择成都大熊猫繁育研究基地育幼期采取不同育幼方式管理的成年雌性大熊猫为研究对象,利用...     

大熊猫母性行为培驯

圈养大熊猫初产母兽弃仔和抚育行为不当是导致幼仔死亡的主要原因之一。针对这种情况 ,从 1 998～ 2 0 0 0年 ,分别采用幼仔模型、尿液、叫声录音、实体和乳汁等多种刺激信号 ,对 1只弃仔的雌性大熊猫 (谱系号 :446)母性行为培训的结果表明 ,首先采用幼仔模型、尿液、叫声录音和乳汁等多种信号的刺激 ,有助于弃仔的初产母兽再接受其幼仔。进一步对母兽抚育行为的培训 ,其母性行为逐年增强 ,并最终掌握各项育幼技能 ,使幼仔存活率得到显著提高。     

Environmental constrains on post-partum ovarian activity in Tanzanian Zebu cows

Milk progesterone measurements were used to study post-partum ovarian activity and risk factors for ovarian dysfunction in Zebu cows reared under a traditional pastoral management system in three villages in Morogoro region, Tanzania. Milk samples for progesterone analysis were collected twice per week from a total of 98 lactations. The most prevalent ovarian dysfunction detected was delayed onset of post-partum ovarian activity and cessation of cyclical ovarian activity after a period of normal ovarian function. Prolonged luteal phases were not observed. Resumption of post-partum ovarian activity was observed in 61 (62.2%) cows. Pregnancy was diagnosed in 43 (43.8%) out of 98 cows and was terminated by abortion in 7 (16.3%) cows. The median number of days from calving to resumption of ovarian activity was lower in cows that calved during the dry season (167 days) as compared with those that calved in the rainy season (200 days, P=0.03), probably because ovarian function was stimulated in cows entering the rainy season first after the puerperal phase had ended. Cyclical ovarian activity ceased in seven (11.5%) cows, and all but one case of cessation of ovarian activity took place during the dry season. Cows in their first and second parities experienced prolonged intervals (244 days) between calving and onset of ovarian activity compared with cows in their third or later parity (172 days, P=0.03). Cows with marked losses in body condition experienced prolonged intervals between calving and onset of ovarian activity (229 days) as compared with cows that lost <1 body condition unit (172 days, P=0.03). The time interval from calving to resumption of ovarian activity varied between the three villages of the study (142, 192 and 229 days, P=0.05), indicating local differences in management practices.     

Reproductive seasonality in female Iberian red deer (Cervus elaphus hispanicus)

This study characterized the seasonal pattern of luteal cyclicity in Iberian red deer (n=16), by measuring plasma progesterone concentrations in hinds (female red deer) twice per week from calving (May and June) 1996 until May 1997. In eight of these hinds we also examined plasma prolactin profiles to assess seasonal responses to photoperiod. Plasma progesterone concentration in the 16 hinds studied indicated that the reproductive pattern is seasonal, and lasts for 5.73 +/- 0.27 months. After calving, progesterone levels remained basal (no luteal activity) for several months, except in a hind that lost her calf just after calving, and thus did not have to suckle it. This hind showed two consecutive estrus cycles in the month following calving, which suggests that suckling has an inhibiting effect on the resumption of ovarian activity. These results also showed that as long as the hinds do not become pregnant, they show between 5 and 10 estrus cycles per reproductive season (8.06 +/- 0.35), ranging between 105 and 249 days from onset of the first cycle to end of the last one. Uninterrupted cycling lasted for 3.5-6.4 months (mean, 4.6 +/- 0.24). Cyclic luteal activity was found from October to February in all hinds, with a smaller, but notable proportion in September (56.25%) and March (68.8%), whereas it was negligible in the remaining period. Our results show a reproductive season similar to or longer than that recorded by other authors. Prolactin plasma concentrations showed a yearly trend following that of photoperiod, with peak concentrations from April to July, a decrease in August, minimal concentrations from September to February and a sharp increase in March.     

Environmental influence on calving interval and estimates of its repeatability in the Murrah buffalo in Sri Lanka

Data on 2375 calvings in 726 Murrah buffalo cows were analysed for the period 1968 to 1979 on two state farms (Ridiyagama and Polonnaruwa) in the dry zone of Sri Lanka. The mean ages at first calving were 51.0 (S.D. 8.6) and 52.1 (S.D. 10.5) months, the calving intervals 530.6 (S.D. 168.2) and 538.6 (S.D. 166.7) days, and the repeatabilities of calving intervals 0.36 ± 0.02 and 0.43 ± 0.02 for the two farms, respectively. The calving interval was significantly influenced (P ? 0.01) by the individual cow, year and season of conception, and parity. Conception during January to March led to the shortest calving interval, and during October to December to the longest. The highest percentage of conceptions occurred some 2–5 months after the peak rainfall.     

Influence of parity on follicular dynamics and resumption of ovarian cycle in postpartum dairy cows

The present study examined ovarian changes preceding the resumption of the ovarian cycle in postpartum dairy cows with different parities under similar body nutritional conditions. In postpartum primi- (n=6), bi- (n=4), and multiparous (n=6) Holstein dairy cows, ovarian ultrasonographic observations starting at 7 days after calving were performed every other day and then daily after the confirmation of clinical signs of oestrus for the detection of postpartum first ovulation. Blood samples were collected at the same time as ultrasonography and analyzed for oestradiol and progesterone to monitor ovarian activity. To evaluate the nutritional condition of the cows, body weight and body condition score (BCS, 1=emaciated to 5=obese) were measured weekly and blood samples for the analysis of glucose, insulin, and non-esterified fatty acid (NEFA) were collected at the same time until postpartum second ovulation. Dominant follicles (>8mm in diameter) of the first follicular wave were detected at 7 days after calving in all cows. The first wave follicle ovulated in five of six multiparous cows, whereas no first wave follicle ovulated in any of the primiparous cows. The days to first ovulation after calving in primiparous cows (31.8+/-8.3 days) were significantly greater (p<0.05) than those in multiparous cows (17.3+/-6.3 days), but were not significantly different from biparous cows (28.8+/-8.6 days). There was a significant relationship between parity and days to first ovulation after calving (p<0.05). BCS was maintained at a level of more than 2.5 during the postpartum period in all cows and there was no influence of parity on postpartum changes in BCS, glucose, insulin, or NEFA throughout the experiment. The present study demonstrated a negative relationship between parity and number of days from calving to first ovulation in dairy cows under similar body nutritional conditions. It is possible that the influence of parity on the resumption of ovarian cycle is modulated by the factors different from the nutrition-related changes during the postpartum period in dairy cows.     

Performance and nursing behaviour of beef cows with different types of calf management

The aim of this experiment was to evaluate the effect of calf management during lactation on dam performance and nursing behaviour. Thirty-six multiparous beef cows (aged 7.5 ± 0.52 years) of Parda de Montaña breed (mean live-weight (LW) at calving 566 ± 9.3 kg) with a moderate body condition (mean 2.6 ± 0.02 on a 1 to 5 scale), were assigned to three nursing frequencies from the day after parturition: Once-daily restricted nursing during a 30 min period at 0800 h (RESTR1), twice-daily restricted nursing during two 30 min periods at 0800 and 1530 h (RESTR2) and ad libitum nursing (ADLIB). Cows were fed throughout the experiment 80 MJ/day of metabolizable energy. Cow–calf behaviour recordings were performed on days 30 and 66 of lactation in each treatment. Blood samples were collected fortnightly to analyse non-esterified fatty acids (NEFA) by an enzymatic colorimetric method, and twice weekly to determine progesterone concentrations by radioimmunoassay. Cow LW losses (P < 0.05), fat-corrected milk yield (P < 0.05) and calf average daily gain (P < 0.01) during lactation were higher in ADLIB. Nursing frequency affected the mean serum concentrations of NEFA, being lower in RESTR1 (0.18 mmol/l; P < 0.05) than in RESTR2 and ADLIB cows (0.29 and 0.25 mmol/l, respectively). The highest occurrence of nursing bouts was observed in ADLIB, leading to greater nursing duration per day (not statistically compared) in this treatment (58.8 ± 5.84 min) than in their restricted nursing counterparts (22.2 ± 1.42 and 34.3 ± 1.16 min, in RESTR1 and RESTR2, respectively). The nursing system did not affect the proportion of cows cycling within 3 months post partum (58%, 46% and 55% in RESTR1, RESTR2 and ADLIB, respectively; P > 0.05). The majority of cows in all treatments showed a short oestrus cycle after first ovulation (75%, 100% and 83%; P > 0.05). In conclusion, the post-partum luteal function in cows managed under continuous access to calves was similar to restricted nursing frequencies, despite the greater suckling intensity of the formers. Restricting calf presence does not enhance the resumption of ovarian activity when suckler cows are managed in moderate nutritional conditions.     

Cervical diameter in relation to uterine and cervical EMG activity in early postpartum dairy cows with retained placentas after PGF2alpha induced calving

The cervix must regain its normal diameter after parturition. Until now, little has been known about the pattern of cervical closure and the possible influences of myometrial and cervical contractions in this process. We continuously measured the cervical diameter with ultrasound cervimetry during the first 48h after calving in six cows with retained fetal membranes, while uterine (n=6) and cervical outer muscular layer (n=4) electromyographic (EMG) activity was measured with bipolar EMG electrodes. We found that the cervical diameter which was 6.2cm (+/-0.7) at 1.4h after calving, initially increased to 9.0cm (+/-1.0) during the first 14.8h (+/-2.8) postpartum. After this time, the diameter decreased gradually to 5.3cm (+/-1.0) at 48h after calving. The overall EMG activity after parturition decreased by 59% (+/-6) and 35% (+/-17) for the uterus and cervix, respectively. The decrease in EMG activity was due to a 50% (+/-7) decrease in EMG amplitudes of the myometrium; the EMG amplitudes of the cervix decreased by only 8% (+/-21) (P>0.05). At the same time in the cervix, burst frequency decreased by 69% (+/-17), while the decrease in burst frequency of the myometrium was only 11% (+/-5) (P>0.05). Uterine myometrial and cervical EMG activity after parturition showed burst patterns. These contractions of the uterus and cervix were accompanied by and correlated with transient dilatations of the caudal cervix. This could have functional relevance in the evacuation of the uterus.     

Effects of abnormal ovarian cycles during pre-service period postpartum on subsequent reproductive performance of high-producing Holstein cows

The primary objective of this study was to investigate the effects of abnormal ovarian cycles during the pre-service postpartum period on subsequent reproductive performance of high-producing Holstein cows. The study was conducted in a commercial dairy farm with approximately 150 lactating cows, in a subtropical region of Japan. Animals were kept in free-stall barn, and fed a total mixed ration. Cows that calved from June 2001 to July 2002 were included in the study. Milk samples were collected twice weekly from 2 to 11 weeks postpartum, and progesterone concentrations in skim milk were determined by ELISA. After a voluntary waiting period of 40 days, cows detected in estrus were bred by artificial insemination (AI). Pregnancy was confirmed by palpation per rectum 40-70 days after AI. Out of a total of 91 cases, 39 (42.9%) had normal ovarian cycles (ovulation within 45 days after calving, followed by normal ovarian cycles), 32 (35.2%) had prolonged luteal phase (i.e. luteal activity for >20 days), and 12 (13.2%) had anovulation or delayed first ovulation (i.e. first ovulation did not occur until >45 days after calving). The remaining (8.8%) had other types of abnormalities. When compared with cows with a normal ovarian cycle, prolonged luteal phase cows had a lower 100 days AI submission rate, conception rate and pregnancy rate (84.2% versus 56.3%; P<0.05, 50% versus 16.7%; P<0.05 and 42.1% versus 9.4%; P<0.01, respectively), and longer intervals to first AI and to conception ( 67+/-6 days versus 98+/-7 days and 95+/-9 days versus 136+/-11 days; P<0.01 for each). Similarly, when compared with cows with normal ovarian cycles, those with anovulation had lower 100 days conception rate and pregnancy rate (50% versus 0%; P<0.05 and 42.1% versus 0%; P<0.01, respectively), and longer intervals to first AI and to conception ( 67+/-6 days versus 93+/-12 days; P<0.05 and 95+/-9 days versus 155+/-14 days; P<0.01, respectively). Survival analysis of the data for calving to conception interval showed that cows with prolonged luteal phase or anovulation were getting pregnant at a slower rate, and took longer to get pregnant than the cows with normal resumption of ovarian cyclicity postpartum. In conclusion, abnormal ovarian cycles during the pre-service period postpartum adversely affected reproductive performance, including AI submission rate, pregnancy rate, interval to first AI, and calving to conception interval in high-producing Holstein cows.     

Seasonal effects of semen collection and artificial insemination on dairy cow conception

The effects of four seasons of semen collection and of artificial insemination on conception in dairy cows were studied. The solstices and equinoxes (December, March, June and September) defined the beginning and/or end of each season. Semen was collected from 973 progeny-test bulls over 8 years at the two Norwegian AI stations at 60.8 degrees N and 63.4 degrees N where artificial light was used to provide a minimum photoperiod of 10 h/day. The effect of using semen of elite bulls during progeny testing and after selection as elite sires also was investigated. Norwegian Red (NRF) cows were inseminated over a 7-year period using progeny test semen and over the last 4 years of the same period using the semen of the elite sires. The probability of conception to only first inseminations for cows up to, and including, the fifth lactation was assessed by 56-day non-return rate (56d NRR) and calving rate. Two data sets were analysed which excluded cows culled within 270 days of AI or included such cows as non-calving. The reasons for culling were categorised as those for fertility problems or all other reasons. Semen was used for AI irrespective of the season in which it had been collected. Season of semen collection did not affect 56d NRR but calving rate was significantly higher (by 0.5-0.8%, approximately; P < 0.01) for semen collected in the December-March period, when photoperiod was increasing, than at other times of the year. The season in which AI was performed showed a peak of 56d NRR in spring for heifers (P < 0.01) and in summer for parous animals (P < 0.01). For calving rate, however, no seasonal peak was found in heifers, whereas pluriparous cows had much higher calving rates in summer and autumn/early winter than late winter and spring (P < 0.01). Semen of elite sires resulted in higher calving rates by 0.5 (NS) to 1.9% (P < 0.01) when used after selection than when used during progeny testing. The difference between the calving rate achieved when the semen from elite sires was used during progeny testing and after selection indicates that farmers select different classes of cows for submission to AI by progeny test bulls and sires. The 56d NRR was not as good as calving rate for assessing seasonal and other effects on conception rates.     

Characterization of the Mediterranean Italian buffaloes melatonin receptor 1A (MTNR1A) gene and its association with reproductive seasonality

The aim of this study was to examine the polymorphism in MTNR1A gene and its relation to reproductive seasonality in Mediterranean Italian buffaloes reared in Sardinia. The mating period and calving of 100 multiparous buffalo-cows were recorded for three years (2005-2008). Genomic DNA was subjected to PCR for the amplification of the exon II, then 40 amplicons were sequenced. The obtained sequence was deposited in GeneBank database (accession number GU817415). PCR products were checked for the presence of HpaI restriction sites and assigned to genotypes “C/C”, “C/T” or “T/T”. Allelic frequency of C and T alleles was 0.44 and 0.56 and genotypic frequency was 26% for genotype C/C, 40% for C/T and 34% for T/T. In the three observed years the animals with C/C genotype showed the highest number of mating in the semester between August and January and their calving mainly occurred from August to September. On the other hand animals with T/T genotype showed mating mostly in the semester between February and July and calving occurred largely from March to May in all the three years. Heterozygous, in all the three years, showed about the same number of animals mated within each six-month period. The results of the present study provide for the first time a partial sequence as well as one polymorphic site of the MTNR1A receptor gene from buffaloes. Moreover our data showed an association between Single Nucleotide Polymorphism and seasonal reproductive activity in these animals.     

Ease of calving, blood chemistry, insulin and bovine growth hormone of newborn calves derived from embryos produced in vitro in culture systems with serum and co-culture or with PVA

Blood chemistry (pH, pCO2, pO2, glucose, lactate) as well as plasma insulin and growth hormone of calves derived from embryos produced under 2 different in vitro culture systems (modified SOFaa with 20% serum and co-culture with bovine oviduct epithelial cells [IVP serum, n=8] or with 3 mg/mL PVA [IVPdefined, n=6]) were compared with those of calves derived from AI (n=5). Calvings were classified according to the ease (unassisted, light traction, heavy traction). Blood samples were taken from the jugular vein of calves at 5, 15, 30 and 60 min, and at 2, 3, 6, 12, 18 and 24 h after delivery, then daily for 6 d. At the second day of life after 4 feedings and a 4-h fasting period, a glucose tolerance test was performed to evaluate glucose metabolism and insulin secretion. Calves in the IVP serum group had higher birth weights than AI calves (LS mean +/- SEM, IVP serum: 45.2 +/- 1.4 kg vs AI: 40.4 +/- 1.7 kg; P < 0.05), while the birth weights of calves in the IVP defined group were in between (IVPdefined: 41.9 +/- 1.6 kg). More IVP serum calves (75%) needed assistance than IVP defined (33%) or AI (40%) calves. The effect of ease of calving vs the effect of embryo culture was compared in relation to blood parameters at birth. There was an effect of ease of calving but not of embryo culture conditions on blood pH, lactate and PCO2. Calves requiring heavy traction had lower pH during the first 3 h after calving, a higher lactate during the first 60 min after calving and a higher pCO2 the first 2 h after calving than calves born unassisted. Calves requiring heavy traction also had lower pH the first 2 h and higher lactate the first 3 h after calving than calves born by light traction. IVP defined calves had lower lactate than IVP serum calves the first 60 min after calving. At 6 h after delivery, all blood parameters had stabilized. There was no effect of either embryo culture or ease of calving on basal insulin and growth hormone level, or the ability of the calves to handle glucose postnatally and during a glucose tolerance test.