乳牛泌乳曲线的数学模型及其在提早选择种公牛中应用的研究

本文采用时间序列分析方法和回归分析方法,对泌乳曲线的数学模型进行了研究,同时采用Kalnan滤波技术提早估计了模型参数;探讨了提早选择种公牛等问题。结果表明,不完全Г函数存在一定误差,平稳自回归模型具有显明的改进效果。在泌乳曲线的模型模拟研究中,应按产犊季节分别研究;采用最小二乘方法求解模型参数,提早预测产量误差较大,运用现代控制理论建立滤波控制系统,用Kalman滤波估计模型参数,比较最小二乘法具有独特优越性。当由Kalman滤波提早估计模型参数后,用平稳自回归模型预测全期产量误差较小。根据预测的总产乳量,运用BLUP原理估计公牛育种值,可提早选择种公牛。     

黄牛头骨研究

随机测量了四川省有代表性的黄牛头骨101头。选择其中重要部位组成头骨矢状图及平面图并进行研究。研究结果认为,达县宣汉黄牛与雅安荥经黄牛无本质区别,在品种改良规划中可初步视为同一地方品种;叙永黄牛与上述两地方品种截然不同,应另行规划。     

西昌黄牛主要器官组织乳酸脱氢酶(LDH)同工酶的研究

本文对西昌黄牛的心肌、肾脏、肌肉(骨骼肌)、肝脏、脾脏、肺脏、睾丸和血清LDH同工酶用聚丙烯酰胺凝胶电泳进行了测定。测定出西昌黄牛主要器官组织基本的酶谱顺序,其中睾丸具有LDH-X带,有些织组还发现有六条区带。     

现代几种公牛选择方法在中国黑白花乳牛中的应用研究

本文设计了牧场、年度和公牛三因素的最小二乘固定模型和BLUP混合模型在PD和MCC法的基础上提出了改进的预期差法,以解决目前一些地区在评定公牛时缺乏谱系遗传值资料和微机的问题。作者用在成渝两地使用的26头黑白花种公牛的2126头女儿的头胎产奶记录,应用上述方法对26头公牛进行了评定。结果表明,两两方法排列的公牛序列间的差异均不大,改进的预期差法较适用于四川目前的情况。     

Effect of plant height at cutting,source and level of fertiliser on yield and nutritional quality of Napier grass (Pennisetum purpureum (L.) Schumach.)

Napier grass (Pennisetum purpureum (L.) Schumach.) was studied using a 5 x 3 factorial experiment arranged in a randomised complete block design with three replications. The treatments were five fertiliser applications (0kg ha^-1 N, 46kg ha^-1 N and 92kg ha^-1 N, 1t ha^-1 and 2t ha^-1 cattle manure) and three plant heights at cutting (0.5m, 1m and 1.5m). The mean dry matter (DM) yield was 8.21t ha^-1 per cut but increased when the plant height at cutting increased and when the level of N fertilisation increased (P<0.05). Neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL), cellulose, calcium, in vitro dry matter digestibility (IVDMD) and metabolisable energy were significantly (P<0.05) affected by plant height at cutting while total ash, crude protein (CP), ADF-ash, hemicelluose and phosphorus were affected by both plant height at cutting and fertiliser level. As plant height at cutting increased from 0.5m to 1.5m, IVDMD declined from 71.74% to 61.03% (P<0.05). Correlations between IVDMD versus CP, NDF, ADF, ADL, cellulose and hemicellulose were high with r = 0.92, -0.94, -0.96, -0.98, -0.83 and 0.74, respectively. CP yield per hectare per day of growth was highest for the 0.5m height at cutting, whereas the digestible DM yield was highest at both the 0.5m and 1.0m cutting height. The results of the present study suggest that Napier grass could be categorised under medium to high quality forage if cut at 0.5m or 1.0m height.     

The use of trees,shrubs and herbs in livestock production by communal farmers in northern KwaZulu-Natal,South Africa

A survey of the use of trees, shrubs and herbs for livestock production was conducted through questionnaires among 90 farmers in the communal areas of northern KwaZulu-Natal in South Africa. The areas surveyed were located at Mtubatuba, Hluhluwe, Kwadlangezwa and Jozini. All the farmers questioned were found to own some form of livestock, mostly the Nguni breed. The commonly perceived sources of constraints on livestock production were external and internal parasites. The well known plants reported to be consumed by the animals were Vitellariopsis arginata and Rhus gueinzii. Most of the farmers (27.7%) used Cissus quadrangularis and Gnidia kraussiana for treating worm infestations and coughs in livestock. Plants used for increasing milk production were Crinum macowanii and Sarcostemma viminale. The well known plant species detrimental to livestock was Moraea spathulata, which causes diarrhoea and death.     

The contribution and direct-use value of livestock to rural livelihoods in the Sand River catchment,South Africa

The productive functions of livestock ownership in communal areas are multipurpose in character, comprising a mix of stock types and a range of goods and services used. When all these multiple uses are accounted for, the cash and direct-use returns of livestock in communal areas can be comparable to commercial systems, although temporally and spatially variable. Yet previous work has generally excluded small stock from such analyses, as well as benefits and costs to non-owning households. This paper presents empirical results of a study in the Sand River catchment, assessing the benefits and costs accruing to owners and non-owners for both cattle and goats within a livelihoods analysis framework. Results indicate that cattle are used for a greater variety of goods and services than are goats. The savings value represented the most important function, followed by milk and then manure. Even if savings value was excluded, cattle ownership made a significant contribution to local livelihoods. Goats also provided a net positive benefit, represented largely by the savings value, followed by meat and cash sales. Non-owners also benefited through donations of manure, milk, draught and meat for free, or at a cheaper rate than alternatives. The majority of non-owners aspired to livestock ownership, although the risk of theft of animals was of growing concern. Averaged across the whole catchment, the net value of goods and services from livestock was just over R400 per hectare, with an annual return to capital of 36%. Cattle contributed the bulk of the value by virtue of their greater numbers and larger size, but on a per kilogramme basis goats provided higher value. Many of the goods and services obtained from livestock were not enumerated in regional or national economic statistics.