EFFECTS OF BOVINE SOMATOTROPIN ON CHANGES IN UDDER DIMENSIONS AFTER CESSATION OF MILKING IN WEST AFRICAN DWARF GOATS

A study was conducted to determine the effects of bovine somatotropin (bST) on changes in udder dimensions (UD) including udder length (UL), udder width (UW), udder circumference (UC) and distance between teats (DT) after cessation of milking in twelve West African Dwarf (WAD) goats, which were divided equally into four treatment groups, each comprising three does. The first group (control, T0) received no bST while the other groups received bST (T1, 20 mg; T2, 40 mg; T3, 60 mg) injected at 2-week intervals commencing from the 5th week postpartum for 8 weeks. Does were milked twice daily (7:30 am and 7:30 pm). Twenty four hours after the twelfth week, measurement of UD commenced for 35 days. The results revealed that UL, UW, UC and DT were significantly (p<0.05) influenced by bST dose, day after cessation of milking and parity and the UD increased with increased doses of bST.  There was maximal distension of udder by day 3 to 5 in treated goats than in the control which was on day 2 before declining progressively up to 35th day after cessation of milking. This showed a greater capacity to retain secretions as explained by the larger udder size. Therefore, the administration of bST to WAD goats during lactation extended its effects on mammary glands after cessation of milking and slowed down the rate of udder regression, thus, enabling the potential of bST treated goats for greater milk synthesis in the next lactation cycle. &nbsp

EFFECTS OF BOVINE SOMATOTROPIN ON THE PATTERN OF MILK YIELD WITHIN AND BETWEEN INJECTION INTERVALS IN WEST AFRICAN DWARF GOATS

Twenty-four West African Dwarf (WAD) goats were used to study the pattern of milk yield response torecombinant bovine somatotropin (rbST) administered in a sustained-delivery vehicle. The goats weredivided equally into four treatment groups, each comprising of six does. The first group (control, T0)received no rbST while the other groups received rbST (T1, 20 mg; T2, 40 mg; T3, 60 mg) injected at 2-week intervals commencing from the 7th week postpartum for 6 weeks. Pattern of milk yield responseto rbST was significantly (p<0.05) influenced by rbST dose, day from rbST treatment, order of rbSTtreatment and parity. Milk yield of treated goats increased from day 1 of treatment, peaked betweenday 5 and day 8 after treatment and progressively decreased until day 14 of treatment but that of thecontrol decreased progressively from day 1 till day 14 of treatment. The mean relative response ofDMY to rbST treatment for T1, T2 and T3 exceeded T0 by 50.36, 68.00 and 71.16 % respectively andsignificantly affected the shape of the lactation curve, thus, improving persistency of lactation. Thepatterns of DMY for T1, T2 and T3 were well-fitted by the Wood’s equations: Y = 16.628n1.728e-0.439n (R2= 63.1), Y = 25.198n0.836e-0.239n (R2 = 75.6) and Y = 0.008n9.081e-1.352n (R2 = 42.3) respectively. Theadministration of 40 mg dose of rbST appears to elicit DMY response that favoured milk yield persistency.But since highest DMY was observed with 60 mg dose of rbST, estimation of optimal dose thatwould elicit maximum DMY response may be required in order to validate the statement. Our findingssuggest that rbST administration to WAD goats after peak of lactation can enhance milk yield, galactopoiesisand persistency of lactation indicating higher milk yield in extended lactation

ESTIMATION OF OPTIMAL DOSE OF BOVINE SOMATOTROPIN FOR MAXIMUM MILK YIELD RESPONSE IN WEST AFRICAN DWARF GOATS

Optimal dose of bovine somatotropin (bST) in a sustained-delivery vehicle required for maximum milkyield response was estimated in twenty-four lactating West African Dwarf (WAD) goats in three 14-dayperiods using quadratic equation. The goats were divided equally into four treatment groups, eachcomprising six does. The first group (control, T0) received no bST while the other groups received bST(T1, 20 mg; T2, 40 mg; T3, 60 mg) injected at 2-week intervals commencing from the 7th week postpartumfor 6 weeks. Does were milked twice daily (7:30 am and 7:30 pm) and milk yield recorded daily.Daily milk yield response (DMY) to bST was significantly (p<0.001) influenced by bST dose, day frombST treatment and parity during the 2nd period of bST treatment but only bST dose and parity significantlyinfluenced (p<0.001) DMY during the 1st and 3rd periods of bST treatment. The mean relativeresponse of DMY of bST-treated goats exceeded the control by 48 – 78 % in the entire periods of bSTadministration. Highest predicted response of 80.5 % in the 3rd period and lowest response of 66.2 %in the 1st period of bST treatment (when compared to the control) were observed, thus indicating thatbST positively affected the shape of the lactation curve for possible higher yield in extended lactation.Although, the trend of observed and predicted optimal doses of bST needed for maximum DMY werewell-fitted by the Quadratic equation during the three periods of bST treatment, it varied inconsistentlywith periods of bST treatment (stages of lactation). Therefore, the uniform optimal dose of 50.71 mgper 2 weeks estimated by quadratic equations; Y = 141.318 + 4.097X – 0.041X2, R2 = 99.90), Y =100.912 + 2.926X – 0.030X2, R2 = 99.49 and Y = 5935.420 + 172.071X – 1.735X2, R2 = 99.49 andneeded for maximum DMY of 242.86 ml, relative DMY of 74 % and cumulative milk yield response of10214.29 ml respectively over the entire periods could be adopted in West African Dwarf goats in orderto reduce the complexity of differential injections administered with respect to stages of lactation

Influence of bull biostimulation, season and parity on resumption of ovarian activity of zebu (Bos indicus) cattle following parturition

Abstract A total of 135 postpartum suckled zebu cows were assigned randomly at calving to two Ž . treatments: cows exposed to vasectomised bulls Mature Bull Exposure, MBE and cows not Ž . exposed to bulls No Bull Exposure, NBE for a period of 150 days postpartum. This study was conducted to determine the influence of bull biostimulation, season and parity on postpartum reproductive performance of Bos indicus cattle. The trials were conducted in two seasons: cows calving in the dry season and cows calving in the rainy season. Cows with an increase in serum Ž . progesterone P concentration of ) 1 ngrml from the weekly blood samples were used to 4 analyse the number of days from calving to the time of resumption of ovarian activity. The introduction of vasectomised bulls shortened the postpartum anoestrus in cattle following calving. Mean interval from calving to resumption of ovarian activity for the MBE cows was 71.7 days, which was significantly earlier following calving than the NBE cows with a duration of 77.8 days. By 60 to 80 days postpartum, the proportion of cows at resumption of postpartum activity for MBE cows was greater than for the NBE cows. Mean interval from calving to resumption of ovarian activity for cows that calved in the dry season was 71.3 days, which was significantly earlier than for cows that calved in the rainy season Ž . 78.6 days . At 60 days postpartum, the proportion of cows at resumption of postpartum ovarin activity for cows that calved in the dry season was greater than the cows that calved in the rainy season. Mean interval from parturition to resumption of ovarian activity for cows with three to five calvings was 65.1 days, which was significantly earlier than the value of 71.2 days for cows ) Corresponding author. Tel.: q234-69-551681; fax: q234-69-51272. Ž . E-mail address: [email protected] P.I. Rekwot . 0378-4320r00r$ -see front matter q 2000 Elsevier Science B.V. All rights reserved. Ž . PII: S 0 3 7 8 -4 3 2 0 0 0 0 0 1 6 3 -9 ( ) P.I. Rekwot et al.r Animal Reproduction Science 63 2000 1-11 2 with one to two calvings. By 60 to 80 days postpartum, the proportion of cows at onset of ovarian activity for cows with three to five calvings was greater than those cows with one to two calvings. Cows that calved in the dry season completed uterine involution by 24.4 days, which was significantly shorter than the duration of 26.5 days for cows that calved in the rainy season. Cows with three to five calvings completed uterine involution earlier than those with one to two calvings. It is concluded that bull-cow biostimulation influences reproductive activity in the cow Ž . possibly through olfactory cues pheromones .

Challenges to Farmers’ Participation In Artificial Insemination (AI) Biotechnology In Nigeria: An Overview

Livestock farming is an important source of animal based food products and income in Nigeria. To improve livestock production in the country, technologies such as artificial insemination have to be understood and transferred properly by Livestock Extension Agents (LEA) to farmers for proper adoption. This technology has been applied for some years in a number of countries using the appropriate extension approaches. Advantages claimed for the practice are the lessening of the risk of spread of disease in livestock, reduction in sterility and increase in fertility, facilitation of improvement in quality, and economy in livestock management. Against this background this paper highlights the benefits of AI technology, factors limiting against AI program in Nigeria, suggest the appropriate extension methods for disseminating the technology and suggest strategies that should be put in place to make AI technology sustainable in livestock production for increased productivity

Challenges to Farmers’ Participation In Artificial Insemination (AI) Biotechnology In Nigeria: An Overview

Livestock farming is an important source of animal based food products and income in Nigeria. To improve livestock production in the country, technologies such as artificial insemination have to be understood and transferred properly by Livestock Extension Agents (LEA) to farmers for proper adoption. This technology has been applied for some years in a number of countries using the appropriate extension approaches. Advantages claimed for the practice are the lessening of the risk of spread of disease in livestock, reduction in sterility and increase in fertility, facilitation of improvement in quality, and economy in livestock management. Against this background this paper highlights the benefits of AI technology, factors limiting against AI program in Nigeria, suggest the appropriate extension methods for disseminating the technology and suggest strategies that should be put in place to make AI technology sustainable in livestock production for increased productivity